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Yoshida T, Choh Y. Leaf trichome-mediated predator effects on the distribution of herbivorous mites within a kidney bean plant. Exp Appl Acarol 2024:10.1007/s10493-024-00915-6. [PMID: 38600348 DOI: 10.1007/s10493-024-00915-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 03/26/2024] [Indexed: 04/12/2024]
Abstract
Some predators prefer to settle on leaf patches with microstructures (e.g., trichomes and domatia), leaving traces on the patches. Herbivorous arthropods, in turn, select leaf patches in response to these traces left by predators. It remains unclear whether traces of predators on leaf patches affect the distribution of herbivorous prey within plants through plant microstructure. Therefore, we examined the distribution of herbivorous mite (Tetranychus urticae) and predatory mite (Phytoseiulus persimilis) by investigating their oviposition pattern. We used a kidney bean plant (Phaseolus vulgaris) with two expanded primary leaves and the first trifoliate leaf, focusing on leaf trichomes as the microstructure. The density of trichomes was higher on the first trifoliate leaf than on the primary leaves and on the abaxial surface of the leaves than on the adaxial surface. Adult female P. persimilis laid more eggs on the first trifoliate leaf to the primary leaves. Although adult female T. urticae preferred to oviposit on the abaxial surface of primary leaves, previous exposure of plants to predators diminished this preference. The altered egg distribution would be a response to the traces of P. persimilis rather than eggs of P. persimilis. Our findings indicate that T. urticae reproduces on leaf patches with traces of predators without altering their oviposition preference. Given that the presence of predator traces is known to reduce the reproduction of T. urticae, it may have a substantial effect on the population of T. urticae in the next generations on kidney bean plants.
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Affiliation(s)
- Tatsuya Yoshida
- Laboratory of Applied Entomology, Department of Horticulture, Chiba University, 648, Matsudo, Chiba, 271-8510, Japan
| | - Yasuyuki Choh
- Laboratory of Applied Entomology, Department of Horticulture, Chiba University, 648, Matsudo, Chiba, 271-8510, Japan.
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2
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Nathalia X, Vinicius M, Danilo Brito R, Felipe G, Rodrigo W. The Influence of Substance Properties on Arthropod Chemical Defenses: A Meta-Analysis. J Chem Ecol 2024; 50:42-51. [PMID: 38133704 DOI: 10.1007/s10886-023-01457-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 08/04/2023] [Accepted: 10/02/2023] [Indexed: 12/23/2023]
Abstract
Among defenses against predation, chemical defenses are possibly the most studied. However, when addressing the effectiveness of those chemical defenses, previous studies did not include properties of the chemical substances themselves. Lipophilicity, for instance, may facilitate crossing membranes, and boiling point may define the duration of the substances in the air. Moreover, other variables may also be relevant: the predator taxon; the prey model chosen to conduct experiments; whether the prey is presented grouped or not in experiments; and whether the chemical defense is a mixture of many substances or only one. To understand how those factors influence chemical defenses' effectiveness, we conducted a multilevel meta-analysis with 43 studies (127 effect sizes), accounting for different types of dependence. We used Akaike Information Criterion (AICc) to select the best model. The model with the lowest AICc value included only the boiling point, which defines how quickly a chemical substance volatilizes. This model indicated that the most effective chemical defenses had lower boiling point values, i.e., higher volatility. Moreover, we did not find chemicals with very low boiling points, suggesting there might be an optimum range of volatility. Other models, including the intercept-only model, were also recovered among the best models, therefore further studies are needed to confirm the relationship between volatility and chemical defenses' effectiveness. Our results highlight the value of incorporating physicochemical properties in the ecological and evolutionary study of chemical defense.
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Affiliation(s)
- Ximenes Nathalia
- Programa de Pós-graduação em Zoologia, Universidade de São Paulo, São Paulo, SP, Brazil.
- Escola de Artes, Ciências e Humanidades, Laboratory of Sensory Ecology and Behavior of Arthropods, Universidade de São Paulo, São Paulo, SP, Brazil.
| | - Moraes Vinicius
- Laboratório de Taxonomia Ecologia e Interações de Aracnídeos, Universidade Federal de Goiás, Goiânia, Brazil
| | | | - Gawryszewski Felipe
- Departamento de Zoologia, Evolutionary Ecology Laboratory, Universidade de Brasília, Brasília, DF, Brazil
| | - Willemart Rodrigo
- Universidade de São Paulo, São Paulo, SP, Brazil
- Escola de Artes, Ciências e Humanidades, Laboratory of Sensory Ecology and Behavior of Arthropods, Universidade de São Paulo, São Paulo, SP, Brazil
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3
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Belgrad BA, Knudson W, Roney SH, Walton WC, Lunt J, Smee DL. Induced defenses as a management tool: Shaping individuals to their environment. J Environ Manage 2023; 338:117808. [PMID: 37003225 DOI: 10.1016/j.jenvman.2023.117808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 02/28/2023] [Accepted: 03/23/2023] [Indexed: 06/19/2023]
Abstract
Many prey species can adjust morphology to reduce predation risk in response to predator cues. Enhancing prey defenses using predator cues may improve survival of cultivated species and enhance species restoration efforts, but assessment of such benefits at industrially relevant scales is needed. We examined how raising a model foundation species, oysters (Crassostrea virginica), under commercial hatchery conditions with cues from two common predator species can improve survival across a variety of predator regimes and environmental conditions. Oysters responded to predators by growing stronger shells than controls, but had subtle variations in shell characteristics depending on the predator species. Predator-induced changes significantly increased oyster survival up to 600% and survivorship was maximized when cue source was matched with local predator regime. Overall, our findings demonstrate the utility of using predator cues to enhance the survival of target species across landscapes and highlight the opportunity to employ nontoxic methods to control pest-based mortality.
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Affiliation(s)
- Benjamin A Belgrad
- 101 Bienville Blvd, Dauphin Island Sea Lab, Dauphin Island, AL, 36528, USA.
| | - William Knudson
- 101 Bienville Blvd, Dauphin Island Sea Lab, Dauphin Island, AL, 36528, USA
| | - Sarah H Roney
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
| | - William C Walton
- Department of Fisheries Science, Virginia Institute of Marine Science, Gloucester Pt., VA, 23062, USA.
| | - Jessica Lunt
- 101 Bienville Blvd, Dauphin Island Sea Lab, Dauphin Island, AL, 36528, USA
| | - Delbert L Smee
- 101 Bienville Blvd, Dauphin Island Sea Lab, Dauphin Island, AL, 36528, USA; Department of Marine Science, University of South Alabama, Mobile, AL 36688, USA.
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4
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Fouilloux CA, Stynoski JL, Yovanovich CAM, Rojas B. Visual environment of rearing sites affects larval response to perceived risk. J Exp Biol 2023:310548. [PMID: 37203595 DOI: 10.1242/jeb.245822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 05/14/2023] [Indexed: 05/20/2023]
Abstract
Turbidity challenges the visual performance of aquatic animals. Here, we use the natural diversity of ephemeral rearing sites occupied by tadpoles of two poison frog species to explore the relationship between environments with limited visibility and individual response to perceived risk. We sampled wild tadpoles of Dendrobates tinctorius, a rearing-site generalist with facultatively cannibalistic tadpoles, and Oophaga pumilio, a small-pool specialist dependent on maternal food-provisioning, to compare how species with diverse natural histories respond to risk having developed in a range of photic environments. Using experimental arenas, we measured tadpole activity and space use first on a black and white background, and then on either black or white backgrounds where tadpoles were exposed to potentially predatory visual stimuli. The effects of rearing environment on D. tinctorius tadpoles were clear: tadpoles from darker pools were less active than tadpoles from brighter pools, and did not respond to either visual stimuli, whereas tadpoles from brighter pools swam more when paired with conspecifics versus odonate larvae, suggesting that tadpoles can visually discriminate between predators. For O. pumilio, tadpoles were more active on experimental backgrounds that more closely matched the luminosity of their rearing sites, but their responses to the two visual stimuli did not differ. Larval specialisation associated with species-specific microhabitat use may underlie the observed responses to visual stimuli. Our findings demonstrate that light availability of wild larval rearing conditions influences the perception of risk in novel contexts, and provides insight into how visually guided animals may respond to sudden environmental disturbances.
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Affiliation(s)
- Chloe A Fouilloux
- University of Jyväskylä, Department of Biology and Environmental Science, P.O. Box 35, 40014, Jyväskylä, Finland
| | - Jennifer L Stynoski
- Clodomiro Picado Institute, University of Costa Rica, Coronado, San José, Costa Rica
| | - Carola A M Yovanovich
- School of Life Sciences, University of Sussex, Biology Road, BN1 9QG, Falmer, Brighton, UK
| | - Bibiana Rojas
- University of Jyväskylä, Department of Biology and Environmental Science, P.O. Box 35, 40014, Jyväskylä, Finland
- Department of Interdisciplinary Life Sciences, Konrad Lorenz Institute of Ethology, University of Veterinary Medicine Vienna, Savoyenstraße 1, 1160, Vienna, Austria
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5
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Turcotte F, Hanke A, McDermid JL. Atlantic bluefin tuna diet variability in the southern Gulf of St. Lawrence, Canada. Mar Environ Res 2023; 187:105949. [PMID: 36940558 DOI: 10.1016/j.marenvres.2023.105949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 02/15/2023] [Accepted: 03/12/2023] [Indexed: 06/18/2023]
Abstract
The abundance of top predators in the southern Gulf of St. Lawrence, Canada, has fluctuated dramatically in recent decades. The associated increase in predation and its effect on the lack of recovery of many fish stocks in the system generates the need for a better understanding of predator-prey relationships and the implementation of an ecosystem approach to fisheries management. This study used stomach content analysis to further describe the diet of Atlantic bluefin tuna in the southern Gulf of St. Lawrence. Teleost fish largely dominated the stomach contents in all years. Previous studies established that Atlantic herring was the main component of the diet by weight, whereas herring was almost absent from the diet in this study. A shift in the diet of Atlantic bluefin tuna has been observed, as it now feeds almost exclusively on Atlantic mackerel. The estimated daily meal varied between years, ranging from 1026 g per day in 2019 to 2360 g per day in 2018. Daily meals and daily rations were calculated and showed substantial year-to-year variation.
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Affiliation(s)
- François Turcotte
- Fisheries and Oceans Canada, Gulf Fisheries Centre, 343 Université Avenue, Moncton, New Brunswick, E1C 9B6, Canada.
| | - Alex Hanke
- Fisheries and Oceans Canada, St. Andrews Biological Station, 125 Marine Science Drive, St. Andrews, New Brunswick, E5B 0E4, Canada
| | - Jenni L McDermid
- Fisheries and Oceans Canada, Gulf Fisheries Centre, 343 Université Avenue, Moncton, New Brunswick, E1C 9B6, Canada
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Moreno-de-Lima PL, Lambertini C, Becker CG, Rebouças R, Toledo LF. Presence of invasive American bullfrogs may reduce infectious disease in a native frog species. Dis Aquat Organ 2022; 149:53-58. [PMID: 35510821 DOI: 10.3354/dao03653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Amphibians breeding in aquatic environments may encounter a myriad of threats during their life cycle. One species known to prey on native amphibians in aquatic habitats is the invasive North American bullfrog Lithobates catesbeianus, which, besides being a voracious predator and competitor, often acts as a pathogen carrier and disease superspreader because it tolerates high infection loads of the frog-killing fungus Batrachochytrium dendrobatidis (Bd). Here, we hypothesized that the presence of the bullfrogs in microcosms should either (1) decrease Bd disease severity in native frog species by discouraging them from using the aquatic environment, or (2) increase the mortality of the native species. We tested these 2 mutually exclusive hypotheses by co-housing the snouted treefrog Scinax x-signatus (native to our study area) with L. catesbeianus in the laboratory, exposing them to Bd, and using qPCR analysis to quantify the resulting Bd infection loads in the native frogs. Our experiment had the following replicated treatments: (1) native-only treatment (3 individuals of S. x-signatus), (2) native-predominant treatment (2 S. x-signatus + 1 L. catesbeianus), and (3) exotic-predominant treatment (1 S. x-signatus + 2 L. catesbeianus). We found that Bd infection loads in the native S. x-signatus were highest in the native-only treatment, and lowest in the exotic-predominant treatment, indicating that bullfrogs may discourage native frogs from occupying the aquatic habitat, thus reducing encounter rates between native frogs and the waterborne pathogen. This effect could be driven by the bullfrogs' predatory behavior and their high philopatry to aquatic habitats. Our results highlight that predation risk adds to the complexity of host-species interactions in Bd epidemiology.
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Affiliation(s)
- Psiquê Laís Moreno-de-Lima
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Departamento de Biologia Animal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, São Paulo 13083-862, Brazil
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Tscholl T, Nachman G, Spangl B, Walzer A. Heat waves affect prey and predators differently via developmental plasticity: who may benefit most from global warming? Pest Manag Sci 2022; 78:1099-1108. [PMID: 34786827 DOI: 10.1002/ps.6722] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 11/12/2021] [Accepted: 11/16/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Climate warming is considered to affect the characteristics of heat waves by increasing their duration, frequency and intensity, which can have dramatic consequences for ectothermic arthropods. However, arthropods may respond to heat waves via plastic modifications, which could differently affect a predator and its prey. We examined this assumption using prominent counterparts in biological control, the predatory mite Phytoseiulus persimilis and its prey, the spider mite Tetranychus urticae. Individuals of both species were separately exposed to mild and extreme heat waves during their juvenile development. RESULTS Both species developed faster during extreme heat waves, but the proportional increase of the developmental rates was higher in the prey. Independent of sex, P. persimilis reached smaller size at maturity under extreme heat waves, whereas the body size modifications were sex-dependent in T. urticae: males became smaller, but females were able to maintain their size. CONCLUSIONS An accelerated development may result in the reduction of the exposure time of susceptible juvenile stages to heat waves and prey stages to predators. Plastic size adjustments caused a shift in the female predator-prey body size ratio in favor of the prey, which may lead to higher heat resistance and reduced predation risk for prey females under extreme heat waves. In conclusion, our findings indicate that species-specific shifts in age and size at maturity may result in lower suppression efficacy of the predator P. persimilis against its prey T. urticae with severe consequences for biological control of spider mites, if global warming continues.
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Affiliation(s)
- Thomas Tscholl
- Department of Crop Sciences, Institute of Plant Protection, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Gösta Nachman
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Bernhard Spangl
- Department of Landscape, Spatial and Infrastructure Sciences, Institute of Statistics, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Andreas Walzer
- Department of Crop Sciences, Institute of Plant Protection, University of Natural Resources and Life Sciences, Vienna, Austria
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Joel AC, Schmitt D, Baumgart L, Menzel F. Insect cuticular hydrocarbon composition influences their interaction with spider capture threads. J Exp Biol 2022; 225:274274. [PMID: 35129200 DOI: 10.1242/jeb.242514] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 02/02/2022] [Indexed: 11/20/2022]
Abstract
Insects represent the main prey of spiders, and spiders and insects co-diversified in evolutionary history. One of the main features characterizing spiders is their web as trap to capture prey. Phylogenetically, the cribellate thread is one of the earliest thread types that was specialized to capture prey. In contrast to capture threads, it lacks adhesive glue and consists of nanofibers, which do not only adhere to insects via van der Waals forces, but also interact with the insects' cuticular hydrocarbon (CHC) layer, thus enhancing adhesion. The CHC layer consist of multiple hydrocarbon types and is highly diverse between species. In this study, we show that CHC adhesion to cribellate capture threads is affected by CHC composition of the insect. We studied the interaction in detail for four different insect species with different CHC profiles and observed a differential migration of CHCs into the thread. The migration depends on the molecular structure of the hydrocarbon types as well as their viscosity, influenced by altering the ambient temperature during interaction. As a consequence, adhesion forces to CHC layers differ depending on their chemical composition. Our results match predictions based on biophysical properties of hydrocarbons, and show that cribellate spiders can exert selection pressure on the CHC composition of their insect prey.
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Affiliation(s)
- Anna-Christin Joel
- RWTH Aachen University, Institute of Zoology, Aachen, Germany.,Johannes Gutenberg-University, Institute of Organismic and Molecular Evolution, Mainz, Germany
| | - Dorothea Schmitt
- Johannes Gutenberg-University, Institute of Organismic and Molecular Evolution, Mainz, Germany
| | - Lucas Baumgart
- RWTH Aachen University, Institute of Zoology, Aachen, Germany
| | - Florian Menzel
- Johannes Gutenberg-University, Institute of Organismic and Molecular Evolution, Mainz, Germany
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Cuthbert RN, Briski E. Temperature, not salinity, drives impact of an emerging invasive species. Sci Total Environ 2021; 780:146640. [PMID: 33774308 DOI: 10.1016/j.scitotenv.2021.146640] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 03/16/2021] [Accepted: 03/17/2021] [Indexed: 06/12/2023]
Abstract
Biological invasions are a growing ecological and socioeconomic problem worldwide. While robust predictions of impactful future invaders are urgently needed, understandings of invader impacts have been challenged by context-dependencies. In aquatic systems in particular, future climate change could alter the impacts of invasive non-native species. Widespread warming coupled with sea freshening may exacerbate ecological impacts of invaders in marine environments, compromising ecosystem structure, function and stability. We examined how multiple abiotic changes affect the potential ecological impact of an emerging invasive non-native species from the Ponto-Caspian region - a notorious origin hotspot for invaders, characterised by high salinity and temperature variation. Using a comparative functional response (feeding rates across prey densities) approach, the potential ecological impacts of the gammarid Pontogammarus maeoticus towards native chironomid prey were examined across a range of current and future temperature (18, 22 °C) and salinity (14, 10, 6, 2 ppt) regimes in a factorial design. Feeding rates of P. maeoticus on prey significantly increased with temperature (by 60%), but were not significantly affected by salinity regime. Gammarids displayed significant Type II functional responses, with attack rates not significantly affected by warming across all salinities. Handling times were, however, shortened by warming, and thus maximum feeding rates significantly increased, irrespective of salinity regime. Functional responses were significantly different following warming at high prey densities under all salinities, except under the ambient 10 ppt. Euryhalinity of invasive non-native species from the Ponto-Caspian region thus could allow sustained ecological impacts across a range of salinity regimes. These results corroborate high invasion success and field impacts of Ponto-Caspian gammarids in brackish through to freshwater ecosystems. Climate warming will likely worsen the potential ecological impact of P. maeoticus. With invasions growing worldwide, quantifications of how combined elements of climate change will alter the impacts of emerging invasive non-native species are needed.
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Affiliation(s)
- Ross N Cuthbert
- GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel, Kiel, Germany.
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10
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Abstract
An injured Shergoldia laevigata Zhu, Hughes & Peng, 2007 (Trilobita, Asaphida) was collected from the Furongian of Guangxi, South China. The injuries occurred in the left thoracic pleurae possessing two marked V-shaped gaps. It led to substantial transverse shortening of the left pleural segments, with barely perceptible traces of healing. This malformation is interpreted as a sub-lethal attack from an unknown predator. The morphology of injuries and the spatial and temporal distribution of predators indicated that the predatory structure might have been the spines on the ganathobase or ganathobase-like structure of a larger arthropod. There were overlapped segments located in the front of the injuries, and slightly dislocated thoracic segments on the left part of the thorax, suggesting that the trilobite had experienced difficulties during molting. The freshly molted trilobite had dragged forward the old exuvia causing the irregular arrangement of segments. This unusual trilobite specimen indicates that the injuries interfered with molting.
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Affiliation(s)
- Ruiwen Zong
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China
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11
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Grenier-Potvin A, Clermont J, Gauthier G, Berteaux D. Prey and habitat distribution are not enough to explain predator habitat selection: addressing intraspecific interactions, behavioural state and time. Mov Ecol 2021; 9:12. [PMID: 33743833 PMCID: PMC7981948 DOI: 10.1186/s40462-021-00250-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 03/01/2021] [Indexed: 06/01/2023]
Abstract
BACKGROUND Movements and habitat selection of predators shape ecological communities by determining the spatiotemporal distribution of predation risk. Although intraspecific interactions associated to territoriality and parental care are involved in predator habitat selection, few studies have addressed their effects simultaneously with those of prey and habitat distribution. Moreover, individuals require behavioural and temporal flexibility in their movement decisions to meet various motivations in a heterogeneous environment. To untangle the relative importance of ecological determinants of predator fine-scale habitat selection, we studied simultaneously several spatial, temporal, and behavioural predictors of habitat selection in territorial arctic foxes (Vulpes lagopus) living within a Greater snow goose (Anser caerulescens atlantica) colony during the reproductive season. METHODS Using GPS locations collected at 4-min intervals and behavioural state classification (active and resting), we quantified how foxes modulate state-specific habitat selection in response to territory edges, den proximity, prey distribution, and habitats. We also assessed whether foxes varied their habitat selection in response to an important phenological transition marked by decreasing prey availability (goose egg hatching) and decreasing den dependency (emancipation of cubs). RESULTS Multiple factors simultaneously played a key role in driving habitat selection, and their relative strength differed with respect to the behavioural state and study period. Foxes avoided territory edges, and reproductive individuals selected den proximity before the phenological transition. Higher goose nest density was selected when foxes were active but avoided when resting, and was less selected after egg hatching. Selection for tundra habitats also varied through the summer, but effects were not consistent. CONCLUSIONS We conclude that constraints imposed by intraspecific interactions can play, relative to prey distribution and habitat characteristics, an important role in the habitat selection of a keystone predator. Our results highlight the benefits of considering behavioural state and seasonal phenology when assessing the flexibility of predator habitat selection. Our findings indicate that considering intraspecific interactions is essential to understand predator space use, and suggest that using predator habitat selection to advance community ecology requires an explicit assessment of the social context in which movements occur.
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Affiliation(s)
- Alexis Grenier-Potvin
- Chaire de recherche du Canada en biodiversité nordique and Centre d'Études Nordiques, Université du Québec à Rimouski, 300 Allée des Ursulines, Rimouski, Québec, G5L 3A1, Canada.
| | - Jeanne Clermont
- Chaire de recherche du Canada en biodiversité nordique and Centre d'Études Nordiques, Université du Québec à Rimouski, 300 Allée des Ursulines, Rimouski, Québec, G5L 3A1, Canada
| | - Gilles Gauthier
- Département de biologie and Centre d'études nordiques, Université Laval, 2325 Rue de l'Université, Québec, Québec, G1V 0A6, Canada
| | - Dominique Berteaux
- Chaire de recherche du Canada en biodiversité nordique and Centre d'Études Nordiques, Université du Québec à Rimouski, 300 Allée des Ursulines, Rimouski, Québec, G5L 3A1, Canada.
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12
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Basu S, Clark RE, Fu Z, Lee BW, Crowder DW. Insect alarm pheromones in response to predators: Ecological trade-offs and molecular mechanisms. Insect Biochem Mol Biol 2021; 128:103514. [PMID: 33359575 DOI: 10.1016/j.ibmb.2020.103514] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 12/11/2020] [Accepted: 12/17/2020] [Indexed: 06/12/2023]
Abstract
Insect alarm pheromones are chemical substances that are synthesized and released in response to predators to reduce predation risk. Alarm pheromones can also be perceived by predators, who take advantage of alarm cues to locate prey. While selection favors evolution of alarm pheromone signals that are not easily detectable by predators, predator evolution selects for better prey detection ability. Here, we review the diversity of alarm signals, and consider the behavioral and ecological conditions under which they have evolved. We show that components of alarm pheromones are similar across many insects, although aphids exhibit different behavioral responses to alarm cues compared to social insects. The effects of alarm pheromones on prey behavior depend on factors such as the concentration of pheromones and the density of conspecifics. We also discuss the molecular mechanisms of alarm pheromone perception underlying the evolutionary arms race between predators and prey, and the function of olfactory proteins and receptors in particular. Our review provides a novel synthesis of the diversity and function of insect alarm pheromones, while suggesting avenues that might better allow researchers to exploit population-level responses to alarm signaling for the sustainable management of pests and vector-borne pathogens.
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Affiliation(s)
- Saumik Basu
- Department of Entomology, Washington State University, Pullman, WA, USA.
| | - Robert E Clark
- Department of Entomology, Washington State University, Pullman, WA, USA
| | - Zhen Fu
- Department of Entomology, Washington State University, Pullman, WA, USA; Department of Entomology, Texas A&M University, College Station, TX, USA
| | - Benjamin W Lee
- Department of Entomology, Washington State University, Pullman, WA, USA
| | - David W Crowder
- Department of Entomology, Washington State University, Pullman, WA, USA
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13
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Buxton M, Nyamukondiwa C, Dalu T, Cuthbert RN, Wasserman RJ. Implications of increasing temperature stress for predatory biocontrol of vector mosquitoes. Parasit Vectors 2020; 13:604. [PMID: 33261665 PMCID: PMC7706185 DOI: 10.1186/s13071-020-04479-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 11/05/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Predators play a critical role in regulating larval mosquito prey populations in aquatic habitats. Understanding predator-prey responses to climate change-induced environmental perturbations may foster optimal efficacy in vector reduction. However, organisms may differentially respond to heterogeneous thermal environments, potentially destabilizing predator-prey trophic systems. METHODS Here, we explored the critical thermal limits of activity (CTLs; critical thermal-maxima [CTmax] and minima [CTmin]) of key predator-prey species. We concurrently examined CTL asynchrony of two notonectid predators (Anisops sardea and Enithares chinai) and one copepod predator (Lovenula falcifera) as well as larvae of three vector mosquito species, Aedes aegypti, Anopheles quadriannulatus and Culex pipiens, across instar stages (early, 1st; intermediate, 2nd/3rd; late, 4th). RESULTS Overall, predators and prey differed significantly in CTmax and CTmin. Predators generally had lower CTLs than mosquito prey, dependent on prey instar stage and species, with first instars having the lowest CTmax (lowest warm tolerance), but also the lowest CTmin (highest cold tolerance). For predators, L. falcifera exhibited the narrowest CTLs overall, with E. chinai having the widest and A. sardea intermediate CTLs, respectively. Among prey species, the global invader Ae. aegypti consistently exhibited the highest CTmax, whilst differences among CTmin were inconsistent among prey species according to instar stage. CONCLUSION These results point to significant predator-prey mismatches under environmental change, potentially adversely affecting natural mosquito biocontrol given projected shifts in temperature fluctuations in the study region. The overall narrower thermal breadth of native predators relative to larval mosquito prey may reduce natural biotic resistance to pests and harmful mosquito species, with implications for population success and potentially vector capacity under global change.
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Affiliation(s)
- Mmabaledi Buxton
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology, Palapye, Botswana
| | - Casper Nyamukondiwa
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology, Palapye, Botswana.
| | - Tatenda Dalu
- Department of Ecology and Resource Management, University of Venda, Thohoyandou, 0950, South Africa
| | - Ross N Cuthbert
- GEOMAR, Helmholtz-Zentrum für Ozeanforschung Kiel, 24105, Kiel, Germany
| | - Ryan J Wasserman
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology, Palapye, Botswana
- Department of Zoology and Entomology, Rhodes University, Makhanda, 6140, South Africa
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14
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Torres LG, Barlow DR, Chandler TE, Burnett JD. Insight into the kinematics of blue whale surface foraging through drone observations and prey data. PeerJ 2020; 8:e8906. [PMID: 32351781 PMCID: PMC7183305 DOI: 10.7717/peerj.8906] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 03/12/2020] [Indexed: 11/20/2022] Open
Abstract
To understand how predators optimize foraging strategies, extensive knowledge of predator behavior and prey distribution is needed. Blue whales employ an energetically demanding lunge feeding method that requires the whales to selectively feed where energetic gain exceeds energetic loss, while also balancing oxygen consumption, breath holding capacity, and surface recuperation time. Hence, blue whale foraging behavior is primarily driven by krill patch density and depth, but many studies have not fully considered surface feeding as a significant foraging strategy in energetic models. We collected predator and prey data on a blue whale (Balaenoptera musculus brevicauda) foraging ground in New Zealand in February 2017 to assess the distributional and behavioral response of blue whales to the distribution and density of krill prey aggregations. Krill density across the study region was greater toward the surface (upper 20 m), and blue whales were encountered where prey was relatively shallow and more dense. This relationship was particularly evident where foraging and surface lunge feeding were observed. Furthermore, New Zealand blue whales also had relatively short dive times (2.83 ± 0.27 SE min) as compared to other blue whale populations, which became even shorter at foraging sightings and where surface lunge feeding was observed. Using an unmanned aerial system (UAS; drone) we also captured unique video of a New Zealand blue whale's surface feeding behavior on well-illuminated krill patches. Video analysis illustrates the whale's potential use of vision to target prey, make foraging decisions, and orient body mechanics relative to prey patch characteristics. Kinematic analysis of a surface lunge feeding event revealed biomechanical coordination through speed, acceleration, head inclination, roll, and distance from krill patch to maximize prey engulfment. We compared these lunge kinematics to data previously reported from tagged blue whale lunges at depth to demonstrate strong similarities, and provide rare measurements of gape size, and krill response distance and time. These findings elucidate the predator-prey relationship between blue whales and krill, and provide support for the hypothesis that surface feeding by New Zealand blue whales is an important component to their foraging ecology used to optimize their energetic efficiency. Understanding how blue whales make foraging decisions presents logistical challenges, which may cause incomplete sampling and biased ecological knowledge if portions of their foraging behavior are undocumented. We conclude that surface foraging could be an important strategy for blue whales, and integration of UAS with tag-based studies may expand our understanding of their foraging ecology by examining surface feeding events in conjunction with behaviors at depth.
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Affiliation(s)
- Leigh G. Torres
- Geospatial Ecology of Marine Megafauna Lab, Marine Mammal Institute, Department of Fisheries and Wildlife, Oregon State University, Newport, OR, United States of America
| | - Dawn R. Barlow
- Geospatial Ecology of Marine Megafauna Lab, Marine Mammal Institute, Department of Fisheries and Wildlife, Oregon State University, Newport, OR, United States of America
| | - Todd E. Chandler
- Geospatial Ecology of Marine Megafauna Lab, Marine Mammal Institute, Oregon State University, Newport, OR, United States of America
| | - Jonathan D. Burnett
- Aerial Information Systems Laboratory, Forest Engineering, Resources and Management, Oregon State University, Corvallis, OR, United States of America
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15
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Xiong W, Song Y, Yang K, Gu Y, Wei Z, Kowalchuk GA, Xu Y, Jousset A, Shen Q, Geisen S. Rhizosphere protists are key determinants of plant health. Microbiome 2020; 8:27. [PMID: 32127034 PMCID: PMC7055055 DOI: 10.1186/s40168-020-00799-9] [Citation(s) in RCA: 83] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 02/05/2020] [Indexed: 05/18/2023]
Abstract
BACKGROUND Plant health is intimately influenced by the rhizosphere microbiome, a complex assembly of organisms that changes markedly across plant growth. However, most rhizosphere microbiome research has focused on fractions of this microbiome, particularly bacteria and fungi. It remains unknown how other microbial components, especially key microbiome predators-protists-are linked to plant health. Here, we investigated the holistic rhizosphere microbiome including bacteria, microbial eukaryotes (fungi and protists), as well as functional microbial metabolism genes. We investigated these communities and functional genes throughout the growth of tomato plants that either developed disease symptoms or remained healthy under field conditions. RESULTS We found that pathogen dynamics across plant growth is best predicted by protists. More specifically, communities of microbial-feeding phagotrophic protists differed between later healthy and diseased plants at plant establishment. The relative abundance of these phagotrophs negatively correlated with pathogen abundance across plant growth, suggesting that predator-prey interactions influence pathogen performance. Furthermore, phagotrophic protists likely shifted bacterial functioning by enhancing pathogen-suppressing secondary metabolite genes involved in mitigating pathogen success. CONCLUSIONS We illustrate the importance of protists as top-down controllers of microbiome functioning linked to plant health. We propose that a holistic microbiome perspective, including bacteria and protists, provides the optimal next step in predicting plant performance. Video Abstract.
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Affiliation(s)
- Wu Xiong
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Key Lab of Plant Immunity, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, People's Republic of China
- Ecology and Biodiversity Group, Department of Biology, Institute of Environmental Biology, Utrecht University, Padualaan 8, 3584, CH, Utrecht, The Netherlands
| | - Yuqi Song
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Key Lab of Plant Immunity, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, People's Republic of China
| | - Keming Yang
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Key Lab of Plant Immunity, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, People's Republic of China
| | - Yian Gu
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Key Lab of Plant Immunity, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, People's Republic of China
| | - Zhong Wei
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Key Lab of Plant Immunity, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, People's Republic of China.
| | - George A Kowalchuk
- Ecology and Biodiversity Group, Department of Biology, Institute of Environmental Biology, Utrecht University, Padualaan 8, 3584, CH, Utrecht, The Netherlands
| | - Yangchun Xu
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Key Lab of Plant Immunity, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, People's Republic of China
| | - Alexandre Jousset
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Key Lab of Plant Immunity, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, People's Republic of China
- Ecology and Biodiversity Group, Department of Biology, Institute of Environmental Biology, Utrecht University, Padualaan 8, 3584, CH, Utrecht, The Netherlands
| | - Qirong Shen
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Key Lab of Plant Immunity, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, People's Republic of China
| | - Stefan Geisen
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Key Lab of Plant Immunity, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, People's Republic of China
- Department of Terrestrial Ecology, Netherlands Institute for Ecology (NIOO-KNAW), 6708, PB, Wageningen, The Netherlands
- Laboratory of Nematology, Wageningen University & Research, 6700, ES, Wageningen, The Netherlands
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16
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Xu Y, Krause AL, Van Gorder RA. Generalist predator dynamics under kolmogorov versus non-Kolmogorov models. J Theor Biol 2020; 486:110060. [PMID: 31689420 DOI: 10.1016/j.jtbi.2019.110060] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 08/14/2019] [Accepted: 10/30/2019] [Indexed: 10/25/2022]
Abstract
Ecosystems often contain multiple species across two or more trophic levels, with a variety of interactions possible. In this paper we study two classes of models for generalist predators that utilize more than one food source. These models fall into two categories: predator - two prey and predator - prey - subsidy models. For the former, we consider a generalist predator which utilizes two distinct prey species, modelled via a Kolmogorov system of equations with Type II response functions. For the latter, we consider a generalist predator which exploits both a prey population and an allochthonous resource which is provided as a subsidy to the system exogenously, again with Type II response functions. This latter class of model is no longer Kolmogorov in form, due to an exogenous forcing term modelling the input of the allochthonous resource into the system. We non-dimensionalize both models, so that their respective parameter spaces may be more easily compared, and study the dynamics possible from each type of model, which will then indicate - for specific parameter regimes - which generalist predator's preferences are more favorable to survival, including the prevalence of coexistence states. We also consider the various non-equilibrium dynamics emergent from such models, and show that the non-Kolmogorov predator - prey - subsidy model of 10 admits more regular dynamics (including steady states and one type of limit cycle), whereas the predator - two prey Kolmogorov model can feature multiple types of limit cycles, as well as multistability resulting in strong sensitivity to initial conditions (with stable limit cycles and steady states both coexisting for the same model parameters). Our results highlight several interesting differences and similarities between Kolmogorov and non-Kolmogorov models for generalist predators.
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Affiliation(s)
- Yifang Xu
- Mathematical Institute, University of Oxford, Andrew Wiles Building, Radcliffe Observatory Quarter, Woodstock Road, Oxford, OX2 6GG, UK
| | - Andrew L Krause
- Mathematical Institute, University of Oxford, Andrew Wiles Building, Radcliffe Observatory Quarter, Woodstock Road, Oxford, OX2 6GG, UK
| | - Robert A Van Gorder
- Department of Mathematics and Statistics, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand.
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17
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Van Colen C, Vanhove B, Diem A, Moens T. Does microplastic ingestion by zooplankton affect predator-prey interactions? An experimental study on larviphagy. Environ Pollut 2020; 256:113479. [PMID: 31679869 DOI: 10.1016/j.envpol.2019.113479] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 10/14/2019] [Accepted: 10/22/2019] [Indexed: 05/20/2023]
Abstract
Litter is omnipresent in the ocean where it can be ingested by marine biota. Although ingestion of microplastics (MPs) is abundantly reported, insights into how MP can influence predator-prey interactions currently limits our understanding of the ecological impact of MPs. Here we demonstrate trophic transfer of MPs from zooplankton to benthic filter feeders, through consumption of contaminated prey (i.e. prey with ingested MP). However, predation rates of contaminated prey were significantly lower as compared to predation rates of prey that had no MPs ingested. As filter feeder clearance rates were not affected by consumption of MPs, the lower predation rates of contaminated prey appear to be primarily explained by disruption in zooplankton swimming behaviour that reduces their filtration risk. This is the first study that shows how MPs can change predator-prey interactions that are involved in the coupling between the pelagic and seabed habitat.
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Affiliation(s)
- Carl Van Colen
- Ghent University, Biology Department, Marine Biology Research Group, Krijgslaan 281 - S8, B 9000 Ghent, Belgium.
| | - Brecht Vanhove
- Ghent University, Biology Department, Marine Biology Research Group, Krijgslaan 281 - S8, B 9000 Ghent, Belgium
| | - Anna Diem
- Ghent University, Biology Department, Marine Biology Research Group, Krijgslaan 281 - S8, B 9000 Ghent, Belgium
| | - Tom Moens
- Ghent University, Biology Department, Marine Biology Research Group, Krijgslaan 281 - S8, B 9000 Ghent, Belgium
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18
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Grinsted L, Schou MF, Settepani V, Holm C, Bird TL, Bilde T. Prey to predator body size ratio in the evolution of cooperative hunting-a social spider test case. Dev Genes Evol 2019; 230:173-184. [PMID: 31768622 DOI: 10.1007/s00427-019-00640-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 10/30/2019] [Indexed: 11/30/2022]
Abstract
One of the benefits of cooperative hunting may be that predators can subdue larger prey. In spiders, cooperative, social species can capture prey many times larger than an individual predator. However, we propose that cooperative prey capture does not have to be associated with larger caught prey per se, but with an increase in the ratio of prey to predator body size. This can be achieved either by catching larger prey while keeping predator body size constant, or by evolving a smaller predator body size while maintaining capture of large prey. We show that within a genus of relatively large spiders, Stegodyphus, subsocial spiders representing the ancestral state of social species are capable of catching the largest prey available in the environment. Hence, within this genus, the evolution of cooperation would not provide access to otherwise inaccessible, large prey. Instead, we show that social Stegodyphus spiders are smaller than their subsocial counterparts, while catching similar sized prey, leading to the predicted increase in prey-predator size ratio with sociality. We further show that in a genus of small spiders, Anelosimus, the level of sociality is associated with an increased size of prey caught while predator size is unaffected by sociality, leading to a similar, predicted increase in prey-predator size ratio. In summary, we find support for our proposed 'prey to predator size ratio hypothesis' and discuss how relaxed selection on large body size in the evolution of social, cooperative living may provide adaptive benefits for ancestrally relatively large predators.
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Affiliation(s)
- Lena Grinsted
- School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK
| | - Mads F Schou
- Department of Biology, Lund University, 22362, Lund, Sweden
| | - Virginia Settepani
- Department of Biology, Aarhus University, Ny Munkegade 114-116, 8000, Aarhus C, Denmark
| | - Christina Holm
- Department of Biology, Aarhus University, Ny Munkegade 114-116, 8000, Aarhus C, Denmark
| | - Tharina L Bird
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology (BIUST), Plot, 10071, Palapye, Botswana
| | - Trine Bilde
- Department of Biology, Aarhus University, Ny Munkegade 114-116, 8000, Aarhus C, Denmark.
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Dudová P, Boukal DS, Klecka J. Prey selectivity and the effect of diet on growth and development of a dragonfly, Sympetrum sanguineum. PeerJ 2019; 7:e7881. [PMID: 31720101 PMCID: PMC6839516 DOI: 10.7717/peerj.7881] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 09/12/2019] [Indexed: 11/20/2022] Open
Abstract
Despite a long tradition of research, our understanding of mechanisms driving prey selectivity in predatory insects is limited. According to optimal foraging theory, predators should prefer prey which provides the highest amount of energy per unit time. However, prey selectivity may also depend on previous diet and specific nutritional demands of the predator. From the long-term perspective, diet composition affects predator fitness. An open question is whether short-term selectivity of predators provides a diet which is optimal in the long-term. To shed more light on these issues, we conducted laboratory experiments on prey selectivity and its long-term consequences in larvae of the dragonfly Sympetrum sanguineum. We conditioned the larvae to one of two prey types, the cladoceran Daphnia magna and larvae of a non-biting midge Chironomus sp., and then exposed them to various combinations of the two prey types. We found that dragonfly larvae conditioned to Chironomus larvae consumed the same amount of D. magna, but significantly less Chironomus larvae compared to dragonfly larvae conditioned to D. magna. However, there was no effect of previous diet on their success of capture and handling time, suggesting a limited role of learning in their ability to process prey. We then tested the long-term effects of diets with different proportions of both prey for survival and growth of the dragonfly larvae. Individuals fed Chironomus-only diet had higher mortality and slower growth than dragonflies fed D. magna, while larvae fed a mixed diet had the highest survival and growth rate. In conclusion, we show that dragonfly larvae fed by Chironomus larvae performed poorly and compensated by preferring D. magna when both prey types were available. The superiority of the mixed diet suggests that a diverse diet may be needed to satisfy nutritional demands in S. sanguineum larvae. We demonstrate that merging short-term predation experiments with relevant data on predator fitness may provide better understanding of predator-prey interactions and conclude that detailed information on the (mis)matches between prey composition and predator nutritional demands is needed for further progress.
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Affiliation(s)
- Pavla Dudová
- Czech Academy of Sciences, Biology Centre, Institute of Entomology, České Budějovice, Czech Republic
- Department of Zoology, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - David S. Boukal
- Czech Academy of Sciences, Biology Centre, Institute of Entomology, České Budějovice, Czech Republic
- Department of Ecosystem Biology & Soil and Water Research Infrastructure, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Jan Klecka
- Czech Academy of Sciences, Biology Centre, Institute of Entomology, České Budějovice, Czech Republic
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20
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Delnat V, Tran TT, Janssens L, Stoks R. Resistance to a chemical pesticide increases vulnerability to a biopesticide: Effects on direct mortality and mortality by predation. Aquat Toxicol 2019; 216:105310. [PMID: 31580997 DOI: 10.1016/j.aquatox.2019.105310] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 09/13/2019] [Accepted: 09/18/2019] [Indexed: 06/10/2023]
Abstract
Pesticide mixtures are increasingly used to fight pest species that developed resistance to pesticides. To assess the pesticide control efficiency and to reduce ecological damage to non-target species, it is important to quantify the effect of these mixtures and compare them with the effect of their single pesticides on pest species, non-target species and their predator-prey interactions. We studied the effects of the chemical pesticide chlorpyrifos (CPF), the biopesticide Bacillus thuringiensis israelensis (Bti) and their mixture both on the direct mortality and on the mortality by predation. We focused on larvae of a CPF-resistant and a non-resistant strain of the vector mosquito Culex quinquefasciatus and its predator, the pygmy backswimmer Plea minutissima. In the CPF-Bti mixture, both pesticides interacted antagonistically for direct mortality. Exposure to the mixture caused equal direct mortality and equal mortality by predation in both strains. As expected, exposure to CPF resulted in less direct mortality and less mortality by predation in the CPF-resistant mosquito strain compared to the non-resistant strain. Notably, Bti caused a higher mortality in the mosquito larvae of the CPF-resistant strain compared to the non-resistant strain. Furthermore, the predator killed more mosquito larvae of the resistant strain compared to the non-resistant strain when exposed before to Bti alone. These observations identify a novel cost of resistance to a chemical pesticide in terms of increased vulnerability to a biopesticide.
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Affiliation(s)
- Vienna Delnat
- Evolutionary Stress Ecology and Ecotoxicology, University of Leuven, Belgium.
| | - Tam T Tran
- Evolutionary Stress Ecology and Ecotoxicology, University of Leuven, Belgium; Institute of Aquaculture, Nha Trang University, Khanh Hoa, Viet Nam.
| | - Lizanne Janssens
- Evolutionary Stress Ecology and Ecotoxicology, University of Leuven, Belgium.
| | - Robby Stoks
- Evolutionary Stress Ecology and Ecotoxicology, University of Leuven, Belgium.
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21
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Sumasgutner P, Terraube J, Coulon A, Villers A, Chakarov N, Kruckenhauser L, Korpimäki E. Landscape homogenization due to agricultural intensification disrupts the relationship between reproductive success and main prey abundance in an avian predator. Front Zool 2019; 16:31. [PMID: 31406493 PMCID: PMC6683578 DOI: 10.1186/s12983-019-0331-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 07/17/2019] [Indexed: 11/29/2022] Open
Abstract
Background Selecting high-quality habitat and the optimal time to reproduce can increase individual fitness and is a strong evolutionary factor shaping animal populations. However, few studies have investigated the interplay between land cover heterogeneity, limitation in food resources, individual quality and spatial variation in fitness parameters. Here, we explore how individuals of different quality respond to possible mismatches between a cue for prey availability (land cover heterogeneity) and the actual fluctuating prey abundance. Results We analyse timing of breeding and reproductive success in a migratory population of Eurasian kestrels (Falco tinnunculus) breeding in nest-boxes, over a full three-year abundance cycle of main prey (voles), and consider several components of individual quality, including body condition, blood parasite infection, and genetic diversity (n = 448 adults) that act on different time scales. Older individuals, and kestrel parents in higher body condition started egg-laying earlier than younger birds and those in lower body condition. Additionally, egg-laying was initiated earlier during the increase and decrease phases (2011 and 2012) than during the low phase of the vole cycle (2013). Nestling survival (ratio of eggs that fledged successfully) was higher in early nests and in heterogeneous landscapes (i.e., mosaic of different habitat types), which was evident during the increase and decrease phases of the vole cycle, but not during the low vole year. Conclusions We found a strong positive effect of landscape heterogeneity on nestling survival, but only when voles were relatively abundant, whereas a difference in the timing of breeding related to territory landscape heterogeneity was not evident. Therefore, landscape heterogeneity appeared as the main driver of high reproductive performance under favourable food conditions. Our results show that landscape homogenization linked to agricultural intensification disrupts the expected positive effect of vole abundance on reproductive success of kestrels. Electronic supplementary material The online version of this article (10.1186/s12983-019-0331-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Petra Sumasgutner
- 1Department of Biology, Section of Ecology, University of Turku, Turku, Finland.,2Department of Integrative Zoology, University of Vienna, Vienna, Austria.,3FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Cape Town, South Africa
| | - Julien Terraube
- 1Department of Biology, Section of Ecology, University of Turku, Turku, Finland.,4Global Change and Conservation Lab. Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Aurélie Coulon
- 5CEFE, CNRS, Univ Montpellier, Univ Paul Valéry Montpellier 3, Montpellier, France.,6Centre d'Ecologie et des Sciences de la Conservation (CESCO), Muséum national d'Histoire naturelle, Centre National de la Recherche Scientifique, Sorbonne Université, Paris, France
| | - Alexandre Villers
- ONCFS, Unité Avifaune Migratrice, Station de Chizé, 405 route de Prissé-la-Charrière, 79360 Villiers-en-Bois, France
| | - Nayden Chakarov
- 8Department of Biology, Molecular Ecology and Evolution Lab, Lund University, Lund, Sweden.,9Department of Animal Behaviour, Bielefeld University, Bielefeld, Germany
| | - Luise Kruckenhauser
- Museum of Natural History Vienna, Central Research Laboratories, Vienna, Austria
| | - Erkki Korpimäki
- 1Department of Biology, Section of Ecology, University of Turku, Turku, Finland
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22
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Fussell EF, Krause AL, Van Gorder RA. Hybrid approach to modeling spatial dynamics of systems with generalist predators. J Theor Biol 2019; 462:26-47. [PMID: 30385311 DOI: 10.1016/j.jtbi.2018.10.054] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2018] [Revised: 10/06/2018] [Accepted: 10/29/2018] [Indexed: 11/16/2022]
Abstract
We consider hybrid spatial modeling approaches for ecological systems with a generalist predator utilizing a prey and either a second prey or an allochthonous resource. While spatial dispersion of populations is often modeled via stepping-stone (discrete spatial patches) or continuum (one connected spatial domain) formulations, we shall be interested in hybrid approaches which we use to reduce the dimension of certain components of the spatial domain, obtaining either a continuum model of varying spatial dimensions, or a mixed stepping-stone-continuum model. This approach results in models consisting of partial differential equations for some of the species which are coupled via reactive boundary conditions to lower dimensional partial differential equations or ordinary differential equations for the other species. In order to demonstrate the use of this approach, we consider two case studies. In the first case study, we consider a one-predator two-prey interaction between beavers, wolves and white-tailed deer in Voyageurs National Park. In the second case study, we consider predator-prey-allochthonous resource interactions between bears, berries and salmon on Kodiak Island. For each case study, we compare the results from the hybrid modeling approach with corresponding stepping-stone and continuum model results, highlighting benefits and limitations of the method. In some cases, we find that the hybrid modeling approach allows for solutions which are easier to simulate (akin to stepping-stone models) while maintaining seemingly more realistic spatial dynamics (akin to full continuum models).
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Affiliation(s)
- Elizabeth F Fussell
- Mathematical Institute, University of Oxford, Andrew Wiles Building, Radcliffe Observatory Quarter, Woodstock Road, Oxford, OX2 6GG, UK
| | - Andrew L Krause
- Mathematical Institute, University of Oxford, Andrew Wiles Building, Radcliffe Observatory Quarter, Woodstock Road, Oxford, OX2 6GG, UK
| | - Robert A Van Gorder
- Mathematical Institute, University of Oxford, Andrew Wiles Building, Radcliffe Observatory Quarter, Woodstock Road, Oxford, OX2 6GG, UK.
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Oudman T, Piersma T, Ahmedou Salem MV, Feis ME, Dekinga A, Holthuijsen S, ten Horn J, van Gils JA, Bijleveld AI. Resource landscapes explain contrasting patterns of aggregation and site fidelity by red knots at two wintering sites. Mov Ecol 2018; 6:24. [PMID: 30598823 PMCID: PMC6300905 DOI: 10.1186/s40462-018-0142-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 11/14/2018] [Indexed: 06/01/2023]
Abstract
BACKGROUND Space use strategies by foraging animals are often considered to be species-specific. However, similarity between conspecific strategies may also result from similar resource environments. Here, we revisit classic predictions of the relationships between the resource distribution and foragers' space use by tracking free-living foragers of a single species in two contrasting resource landscapes. At two main non-breeding areas along the East-Atlantic flyway (Wadden Sea, The Netherlands and Banc d'Arguin, Mauritania), we mapped prey distributions and derived resource landscapes in terms of the predicted intake rate of red knots (Calidris canutus), migratory molluscivore shorebirds. We tracked the foraging paths of 13 and 38 individual red knots at intervals of 1 s over two and five weeks in the Wadden Sea and at Banc d'Arguin, respectively. Mediated by competition for resources, we expected aggregation to be strong and site fidelity weak in an environment with large resource patches. The opposite was expected for small resource patches, but only if local resource abundances were high. RESULTS Compared with Banc d'Arguin, resource patches in the Wadden Sea were larger and the maximum local resource abundance was higher. However, because of constraints set by digestive capacity, the average potential intake rates by red knots were similar at the two study sites. Space-use patterns differed as predicted from these differences in resource landscapes. Whereas foraging red knots in the Wadden Sea roamed the mudflats in high aggregation without site fidelity (i.e. grouping nomads), at Banc d'Arguin they showed less aggregation but were strongly site-faithful (i.e. solitary residents). CONCLUSION The space use pattern of red knots in the two study areas showed diametrically opposite patterns. These differences could be explained from the distribution of resources in the two areas. Our findings imply that intraspecific similarities in space use patterns represent responses to similar resource environments rather than species-specificity. To predict how environmental change affects space use, we need to understand the degree to which space-use strategies result from developmental plasticity and behavioural flexibility. This requires not only tracking foragers throughout their development, but also tracking their environment in sufficient spatial and temporal detail.
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Affiliation(s)
- Thomas Oudman
- NIOZ Royal Netherlands Institute for Sea Research, Department of Coastal Systems, and Utrecht University, P.O. Box 59, 1790 AB Den Burg, Texel The Netherlands
- Centre for Biological Diversity, School of Biology, University of St Andrews, Fife, KY16 9TF UK
| | - Theunis Piersma
- NIOZ Royal Netherlands Institute for Sea Research, Department of Coastal Systems, and Utrecht University, P.O. Box 59, 1790 AB Den Burg, Texel The Netherlands
- Rudi Drent Chair in Global Flyway Ecology, Conservation Ecology Group, Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, PO Box 11103, 9700 CC Groningen, The Netherlands
| | - Mohamed V. Ahmedou Salem
- EBIOME Ecobiologie Marine et Environnement, Département de Biologie, L’université de Nouakchott Al-Aasriya, BP. 880 Nouakchott, Mauritania
| | - Marieke E. Feis
- NIOZ Royal Netherlands Institute for Sea Research, Department of Coastal Systems, and Utrecht University, P.O. Box 59, 1790 AB Den Burg, Texel The Netherlands
- Present Address: Sorbonne Université, CNRS, Station Biologique de Roscoff, Laboratoire Adaptation et Diversité en Milieu Marin, UMR 7144, CS90074, 29688 Roscoff Cedex, France
| | - Anne Dekinga
- NIOZ Royal Netherlands Institute for Sea Research, Department of Coastal Systems, and Utrecht University, P.O. Box 59, 1790 AB Den Burg, Texel The Netherlands
| | - Sander Holthuijsen
- NIOZ Royal Netherlands Institute for Sea Research, Department of Coastal Systems, and Utrecht University, P.O. Box 59, 1790 AB Den Burg, Texel The Netherlands
| | - Job ten Horn
- NIOZ Royal Netherlands Institute for Sea Research, Department of Coastal Systems, and Utrecht University, P.O. Box 59, 1790 AB Den Burg, Texel The Netherlands
| | - Jan A. van Gils
- NIOZ Royal Netherlands Institute for Sea Research, Department of Coastal Systems, and Utrecht University, P.O. Box 59, 1790 AB Den Burg, Texel The Netherlands
| | - Allert I. Bijleveld
- NIOZ Royal Netherlands Institute for Sea Research, Department of Coastal Systems, and Utrecht University, P.O. Box 59, 1790 AB Den Burg, Texel The Netherlands
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Bleicher SS, Ylönen H, Käpylä T, Haapakoski M. Olfactory cues and the value of information: voles interpret cues based on recent predator encounters. Behav Ecol Sociobiol 2018; 72:187. [PMID: 30573941 DOI: 10.1007/s00265-018-2600-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 11/04/2018] [Accepted: 11/09/2018] [Indexed: 12/01/2022]
Abstract
Abstract Prey strategically respond to the risk of predation by varying their behavior while balancing the tradeoffs of food and safety. We present here an experiment that tests the way the same indirect cues of predation risk are interpreted by bank voles, Myodes glareolus, as the game changes through exposure to a caged weasel. Using optimal patch use, we asked wild-caught voles to rank the risk they perceived. We measured their response to olfactory cues in the form of weasel bedding, a sham control in the form of rabbit bedding, and an odor-free control. We repeated the interviews in a chronological order to test the change in response, i.e., the changes in the value of the information. We found that the voles did not differentiate strongly between treatments pre-exposure to the weasel. During the exposure, vole foraging activity was reduced in all treatments, but proportionally increased in the vicinity to the rabbit odor. Post-exposure, the voles focused their foraging in the control, while the value of exposure to the predator explained the majority of variation in response. Our data also suggested a sex bias in interpretation of the cues. Given how the foragers changed their interpretation of the same cues based on external information, we suggest that applying predator olfactory cues as a simulation of predation risk needs further testing. For instance, what are the possible effective compounds and how they change “fear” response over time. The major conclusion is that however effective olfactory cues may be, the presence of live predators overwhelmingly affects the information voles gained from these cues. Significance statement In ecology, “fear” is the strategic response to cues of risk an animal senses in its environment. The cues suggesting the existence of a predator in the vicinity are weighed by an individual against the probability of encounter with the predator and the perceived lethality of an encounter with the predator. The best documented such response is variation in foraging tenacity as measured by a giving-up density. In this paper, we show that an olfactory predator cue and the smell of an interspecific competitor result in different responses based on experience with a live-caged predator. This work provides a cautionary example of the risk in making assumptions regarding olfactory cues devoid of environmental context. Electronic supplementary material The online version of this article (10.1007/s00265-018-2600-9) contains supplementary material, which is available to authorized users.
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Lawrence MJ, Godin JGJ, Cooke SJ. Does experimental cortisol elevation mediate risk-taking and antipredator behaviour in a wild teleost fish? Comp Biochem Physiol A Mol Integr Physiol 2018; 226:75-82. [PMID: 30099116 DOI: 10.1016/j.cbpa.2018.08.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 07/06/2018] [Accepted: 08/03/2018] [Indexed: 10/28/2022]
Abstract
The hypothalamic-pituitary-interrenal (HPI) axis is centrally implicated in stressor mitigation in teleost fishes. Sustained HPI axis activation can be detrimental to the physiological functioning of an organism and can result in fitness-related trade-offs. Predator-induced mortality is known to be higher in stressed fish than in unstressed conspecifics, suggesting a role for the HPI axis in mediating fish behaviour. However, the underlying specific mechanism(s) for this phenomenon is(are) unknown. The purpose of the current study was to address how the HPI axis influences risk-taking, and antipredator behaviours in a wild teleost, the pumpkinseed sunfish (Lepomis gibbosus). Here, individual juvenile pumpkinseed were implanted either with cocoa butter as a sham control or with a biologically-relevant concentration of cortisol. Forty-eight hours post-implantation, fish were assessed for behavioural metrics associated with boldness and risk taking in three sequential behavioural tests: (i) a predation-risk test, (ii) an exploration tendency test, and (iii) a shoaling tendency test, with test order randomized among different trials. Cortisol treatment had no influence on antipredator, exploratory, or shoaling behaviours. However, post-attack swimming duration (in predation-risk test) and exploratory activity (in Z-maze exploration test) were significantly affected by body mass. Collectively, our results indicate that cortisol may not have a role in mediating sociability, boldness, and risk-taking behaviours in pumpkinseed sunfish, at least under the current laboratory conditions. However, cortisol may nonetheless play a role in mediating predator-prey interactions in fishes in more natural environmental settings that were not considered here.
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Affiliation(s)
- Michael J Lawrence
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology, Carleton University, Ottawa, ON K1S 5B6, Canada.
| | - Jean-Guy J Godin
- Department of Biology, Carleton University, Ottawa, ON K1S 5B6, Canada
| | - Steven J Cooke
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology, Carleton University, Ottawa, ON K1S 5B6, Canada
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Rodríguez-Morales D, Rico-Gray V, García-Franco JG, Ajuria-Ibarra H, Hernández-Salazar LT, Robledo-Ospina LE, Rao D. Context-dependent crypsis: a prey's perspective of a color polymorphic predator. Naturwissenschaften 2018; 105:36. [PMID: 29754205 DOI: 10.1007/s00114-018-1562-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 05/04/2018] [Accepted: 05/07/2018] [Indexed: 12/11/2022]
Abstract
Many animals use body coloration as a strategy to communicate with conspecifics, prey, and predators. Color is a trade-off for some species, since they should be visible to conspecifics but cryptic to predators and prey. Some flower-dwelling predators, such as crab spiders, are capable of choosing the color of flowers where they ambush flower visitors and pollinators. In order to avoid being captured, visitors evaluate flowers visually before landing. The crab spider Mecaphesa dubia is a polymorphic species (white/purple color morphs), which inhabits the flower heads of a dune plant, Palafoxia lindenii. Using full-spectrum photography of spiders and flowers, we evaluated how honeybees perceived the spiders at different distances. Using visual modeling, we obtained the chromatic and achromatic contrasts of the spiders on flower heads as perceived by honeybees. Purple morphs were found mainly on the receptacle area and white morphs were equally likely to be found in the flowers and receptacle. According to theoretical modeling, white morphs were visible to honeybees from a distance of 10 cm in receptacle area but appeared to be cryptic in the flower area. Purple morphs were cryptic on the receptacle and less so when they were on the flowers. Spiders on flower heads are predicted to be more easily detected by honeybees using chromatic contrast. Our study shows that the conspicuousness of flower dwelling spiders to honeybees depends on the color morph, the distance of observation, and the position of spider on the flower head.
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Affiliation(s)
- D Rodríguez-Morales
- Instituto de Neuroetología, Universidad Veracruzana, Av. Luis Castelazo, Col. Industrial Animas, Xalapa, 91190, Veracruz, Mexico.
| | - V Rico-Gray
- Instituto de Neuroetología, Universidad Veracruzana, Av. Luis Castelazo, Col. Industrial Animas, Xalapa, 91190, Veracruz, Mexico
| | - J G García-Franco
- Red de Ecología Funcional, Instituto de Ecología, A.C. Carretera Antigua a Coatepec 351, El Haya, Xalapa, 91070, Veracruz, Mexico
| | - H Ajuria-Ibarra
- Instituto de Biotecnologia y Ecologia Aplicada, Universidad Veracruzana, Av. Culturas Veracruzanas No. 101, Xalapa, 91090, Veracruz, Mexico
| | - L T Hernández-Salazar
- Instituto de Neuroetología, Universidad Veracruzana, Av. Luis Castelazo, Col. Industrial Animas, Xalapa, 91190, Veracruz, Mexico
| | - L E Robledo-Ospina
- Red de Ecoetología, Instituto de Ecología, A.C. Carretera antigua a Coatepec No. 351, Xalapa, 91070, Veracruz, Mexico.,Grupo de Aracnología, Universidad de Caldas, Calle 65 No. 26-10, Manizales, Colombia
| | - D Rao
- Instituto de Biotecnologia y Ecologia Aplicada, Universidad Veracruzana, Av. Culturas Veracruzanas No. 101, Xalapa, 91090, Veracruz, Mexico
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Abstract
Many aquatic organisms detect the presence of moving objects in their environment, such as predators, by sensing the hydrodynamic disturbances the movements produce. The resultant water flow is readily detectable by stationary organisms, but free-swimming organisms are carried with the surrounding water and may not detect the bulk surrounding flow, which limits the available information about the source. We have developed a theory that clarifies what information is contained in disturbances generated by an attacking predator that is available to a free-swimming organism and might be extracted from local flow deformations alone. The theory shows that, depending on how well the deformations can be measured in space and time, an organism can reduce the range of possible locations, speeds, sizes, and arrival times of the predator. We apply the theory to planktonic copepods that have mechanosensory hairs along a pair of antennules. The study reveals the presence of "blind spots," potential ambiguities in resolving from which of two sides a predator attacks, and whether it generates a bow wave or suction. Our findings lead to specific testable hypotheses concerning optimal escape strategies, which are helpful for interpreting the behavior of evasive prey and designing free-swimming robots with sensory capabilities.
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Eacock A, Rowland HM, Edmonds N, Saccheri IJ. Colour change of twig-mimicking peppered moth larvae is a continuous reaction norm that increases camouflage against avian predators. PeerJ 2017; 5:e3999. [PMID: 29158965 PMCID: PMC5691783 DOI: 10.7717/peerj.3999] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 10/17/2017] [Indexed: 01/15/2023] Open
Abstract
Camouflage, and in particular background-matching, is one of the most common anti-predator strategies observed in nature. Animals can improve their match to the colour/pattern of their surroundings through background selection, and/or by plastic colour change. Colour change can occur rapidly (a few seconds), or it may be slow, taking hours to days. Many studies have explored the cues and mechanisms behind rapid colour change, but there is a considerable lack of information about slow colour change in the context of predation: the cues that initiate it, and the range of phenotypes that are produced. Here we show that peppered moth (Biston betularia) larvae respond to colour and luminance of the twigs they rest on, and exhibit a continuous reaction norm of phenotypes. When presented with a heterogeneous environment of mixed twig colours, individual larvae specialise crypsis towards one colour rather than developing an intermediate colour. Flexible colour change in this species has likely evolved in association with wind dispersal and polyphagy, which result in caterpillars settling and feeding in a diverse range of visual environments. This is the first example of visually induced slow colour change in Lepidoptera that has been objectively quantified and measured from the visual perspective of natural predators.
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Affiliation(s)
- Amy Eacock
- Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Hannah M. Rowland
- Predators and Prey Research Group, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Nicola Edmonds
- Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Ilik J. Saccheri
- Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
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Pickering TR, Poirier LA, Barrett TJ, McKenna S, Davidson J, Quijón PA. Non-indigenous predators threaten ecosystem engineers: Interactive effects of green crab and oyster size on American oyster mortality. Mar Environ Res 2017; 127:24-31. [PMID: 28336053 DOI: 10.1016/j.marenvres.2017.03.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 02/27/2017] [Accepted: 03/10/2017] [Indexed: 06/06/2023]
Abstract
Non-indigenous green crabs (Carcinus maenas) are emerging as important predators of autogenic engineers like American oysters (Crassostrea virginica) throughout the eastern seaboard of Canada and the United States. To document the spreading distribution of green crabs, we carried out surveys in seven sites of Prince Edward Island during three fall seasons. To assess the potential impact of green crabs on oyster mortality in relation to predator and prey size, we conducted multiple predator-prey manipulations in the field and laboratory. The surveys confirmed an ongoing green crab spread into new productive oyster habitats while rapidly increasing in numbers in areas where crabs had established already. The experiments measured mortality rates on four sizes of oysters exposed to three sizes of crab, and lasted 3-5 days. The outcomes of experiments conducted in Vexar® bags, laboratory tanks and field cages were consistent and were heavily dependent on both crab size and oyster size: while little predation occurred on large oysters, large and medium green crabs preyed heavily on small sizes. Oysters reached a refuge within the 35-55 mm shell length range; below that range, oysters suffered high mortality due to green crab predation and thus require management measures to enhance their survival. These results are most directly applicable to aquaculture operations and restoration initiatives but have implications for oyster sustainability.
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Affiliation(s)
- Tyler R Pickering
- Department of Biology, University of Prince Edward Island, 550 University Avenue, Charlottetown, PE, C1A 4P3, Canada
| | - Luke A Poirier
- Department of Biology, University of Prince Edward Island, 550 University Avenue, Charlottetown, PE, C1A 4P3, Canada
| | - Timothy J Barrett
- Minnow Environmental Inc., 159 Water Street, St. Andrews, NB, E5B 1A7, Canada
| | - Shawn McKenna
- Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, 550 University Avenue, Charlottetown, PE, C1A 4P3, Canada
| | - Jeff Davidson
- Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, 550 University Avenue, Charlottetown, PE, C1A 4P3, Canada
| | - Pedro A Quijón
- Department of Biology, University of Prince Edward Island, 550 University Avenue, Charlottetown, PE, C1A 4P3, Canada.
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Ntelezos A, Guarato F, Windmill JFC. The anti-bat strategy of ultrasound absorption: the wings of nocturnal moths (Bombycoidea: Saturniidae) absorb more ultrasound than the wings of diurnal moths (Chalcosiinae: Zygaenoidea: Zygaenidae). Biol Open 2017; 6:109-117. [PMID: 27913454 PMCID: PMC5278430 DOI: 10.1242/bio.021782] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The selection pressure from echolocating bats has driven the development of a diverse range of anti-bat strategies in insects. For instance, several studies have proposed that the wings of some moths absorb a large portion of the sound energy contained in a bat's ultrasonic cry; as a result, the bat receives a dampened echo, and the moth becomes invisible to the bat. To test the hypothesis that greater exposure to bat predation drives the development of higher ultrasound absorbance, we used a small reverberation chamber to measure the ultrasound absorbance of the wings of nocturnal (Bombycoidea: Saturniidae) and diurnal moths (Chalcosiinae: Zygaenoidea: Zygaenidae). The absorption factor of the nocturnal saturniids peaks significantly higher than the absorption factor of the diurnal chalcosiines. However, the wings of the chalcosiines absorb more ultrasound than the wings of some diurnal butterflies. Following a phylogenetic analysis on the character state of diurnality/ nocturnality in the Zygaenidae, we propose that diurnality in the Chalcosiinae is plesiomorphic (retained); hence, the absorbance of their wings is probably not a vestigial trait from an ancestral, nocturnal form but an adaptation to bat activity that overlaps their own. On a within-species level, females of the saturniids Argema mittrei and Samia cynthia ricini have significantly higher absorption factors than the males. In the female S. c. ricini, the higher absorption factor corresponds to a detection distance by bats that is at best 20-30% shorter than that of the male. Summary: Moth wings partly absorb the ultrasonic calls of bats to reduce predation. Different moths fly at night or day, and this work compares their absorption of ultrasound.
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Affiliation(s)
- Athanasios Ntelezos
- Centre for Ultrasonic Engineering, Department of Electronic and Electrical Engineering, University of Strathclyde, 204 George Street, Glasgow, G1 1XW, UK
| | - Francesco Guarato
- Centre for Ultrasonic Engineering, Department of Electronic and Electrical Engineering, University of Strathclyde, 204 George Street, Glasgow, G1 1XW, UK
| | - James F C Windmill
- Centre for Ultrasonic Engineering, Department of Electronic and Electrical Engineering, University of Strathclyde, 204 George Street, Glasgow, G1 1XW, UK
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Zhu D, Ke X, Wu L, Li Z, Christie P, Luo Y. Ecotoxicity of cadmium in a soil collembolan-predatory mite food chain: Can we use the 15N labeled litter addition method to assess soil functional change? Environ Pollut 2016; 219:37-46. [PMID: 27661726 DOI: 10.1016/j.envpol.2016.09.051] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 09/08/2016] [Accepted: 09/15/2016] [Indexed: 06/06/2023]
Abstract
Effects of cadmium (Cd) on predator-prey relationships and soil ecological function are poorly understood and there are few methods available to measure soil functional change. Thus, we structured a soil-dwelling food chain containing the predatory mite Hypoaspis aculeifer and its collembolan prey Folsomia candida to study the effects of Cd exposure for eight weeks in a spiked soil aged for five years. The 15N labeled litter was added as food to analyze the change in nitrogen (N) transfer content. H. aculeifer reproduction and growth and the survival and reproduction of F. candida were all negatively affected by Cd exposure, and H. aculeifer reproduction was the most sensitive parameter. The sensitivity responses of F. candida and H. aculeifer were different from those using the previous single species test. The results suggest that predator-prey interactions might influence the toxicity of Cd by predation and food restriction. Cadmium lethal body concentrations of adults and juveniles of F. candida and H. aculeifer juveniles were 500-600, 180-270 and 8-10 μg g-1, respectively. The content of N transfer from litter to animals in the food chain decreased significantly with increasing soil Cd concentration between 100 and 400 mg kg-1. The results suggest that the 15N labeled litter addition method is potentially useful for quantitative assessment of soil functional change for further risk assessment purposes.
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Affiliation(s)
- Dong Zhu
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Xin Ke
- Institute of Plant Physiology and Ecology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China.
| | - Longhua Wu
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
| | - Zhu Li
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Peter Christie
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Yongming Luo
- Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China
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Luquet E, Tariel J. Offspring reaction norms shaped by parental environment: interaction between within- and trans-generational plasticity of inducible defenses. BMC Evol Biol 2016; 16:209. [PMID: 27733114 PMCID: PMC5062831 DOI: 10.1186/s12862-016-0795-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 10/07/2016] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Within-generational plasticity (WGP) and transgenerational plasticity (TGP) are mechanisms allowing rapid adaptive responses to fluctuating environments without genetic change. These forms of plasticity have often been viewed as independent processes. Recent evidence suggests that WGP is altered by the environmental conditions experienced by previous generations (i.e., TGP). In the context of inducible defenses, one of the most studied cases of plasticity, the WGP x TGP interaction has been poorly investigated. RESULTS We provide evidence that TGP can alter the reaction norms of inducible defenses in a freshwater snail. The WGP x TGP interaction patterns are trait-specific and lead to decreased slope of reaction norms (behaviour and shell thickness). Offspring from induced parents showed a higher predator avoidance behaviour and a thicker shell than snails from non-induced parents in no predator-cue environment while they reached similar defenses in predator-cue environment. The WGP x TGP interaction further lead to a switch from a plastic towards a constitutive expression of defenses for shell dimensions (flat reaction norm). CONCLUSIONS WGP-alteration by TGP may shape the adaptive responses to environmental change and then has a substantial importance to understand the evolution of plasticity.
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Affiliation(s)
- Emilien Luquet
- CNRS UMR 5023 Ecologie des Hydrosystèmes Naturels et Anthropisés, Université Claude Bernard Lyon1, Université de Lyon, 43 Bd du 11 Novembre 1918, 69622, Villeurbanne cedex, France.
| | - Juliette Tariel
- CNRS UMR 5023 Ecologie des Hydrosystèmes Naturels et Anthropisés, Université Claude Bernard Lyon1, Université de Lyon, 43 Bd du 11 Novembre 1918, 69622, Villeurbanne cedex, France
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Ferretti F, Lovari S. Predation may counteract climatic change as a driving force for movements of mountain ungulates. Behav Processes 2016; 129:101-4. [PMID: 27312822 DOI: 10.1016/j.beproc.2016.06.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 06/10/2016] [Accepted: 06/11/2016] [Indexed: 11/20/2022]
Abstract
Temperature variations are expected to influence altitudinal movements of mountain herbivores and, in turn, those of their predators, but relevant information is scarce. We evaluated monthly relationships between temperature and altitude used by a large mountain-dwelling herbivore, the Himalayan tahr Hemitragus jemlahicus, and its main predator, the snow leopard Panthera uncia, in an area of central Himalaya for five consecutive years (2006-2010). In contrast to expectations, there was no significant direct relationship between altitude of tahr sightings and temperature. The mean altitude of tahr sightings decreased by c. 200m throughout our study. As expected, snow leopard movements tracked those of tahr, although the core area of the snow leopard did not move downwards. Tahr remained the staple of the snow leopard diet: we suggest that the former did not move upwards in reaction to higher temperature to avoid encounters with the latter. Avoidance of competition with the larger common leopard Panthera pardus at lower altitudes could explain why snow leopards did not shift their core area downwards. Apparently, interspecific interactions (predation; competition) influenced movements of Himalayan tahr and snow leopards more than climatic variations.
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Spain EM, Núñez ME, Kim HJ, Taylor RJ, Thomas N, Wengen MB, Dalleska NF, Bromley JP, Schermerhorn KH, Ferguson MA. Identification and differential production of ubiquinone-8 in the bacterial predator Bdellovibrio bacteriovorus. Res Microbiol 2016; 167:413-23. [PMID: 27106259 DOI: 10.1016/j.resmic.2016.04.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 01/16/2016] [Accepted: 04/02/2016] [Indexed: 01/04/2023]
Abstract
Bdellovibrio bacteriovorus 109J, a predatory bacterium with potential as a bacterial control agent, can exist in several lifestyles that differ both in predatory capacity and color. We determined that levels of ubiquinone-8 contribute to the distinctive but variable yellow color of different types of Bdellovibrio cells. Steady-state ubiquinone-8 concentrations did not differ markedly between conventional predatory and host-independent B. bacteriovorus despite upregulation of a suite of ubiquinone-8 synthesis genes in host-independent cells. In contrast, in spatially organized B. bacteriovorus films, the yellow inner regions contain significantly higher ubiquinone-8 concentrations than the off-white outer regions. Correspondingly, RT-PCR analysis reveals that the inner region, previously shown to consist primarily of active predators, clearly expresses two ubiquinone biosynthesis genes, while the outer region, composed mainly of quiescent or stalled bdelloplasts, expresses those genes weakly or not at all. Moreover, B. bacteriovorus cells in the inner region of week-old interfacial films, which are phenotypically attack-phase, have much higher UQ8 levels than regular attack-phase bdellovibrios, most likely because their "trapped" state prevents a high expenditure of energy to power flagellar motion.
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Affiliation(s)
- Eileen M Spain
- Department of Chemistry, Occidental College, 1600 Campus Rd, Los Angeles, CA 90041, USA.
| | - Megan E Núñez
- Department of Chemistry, Wellesley College, 106 Central St. Wellesley, MA 02481, USA.
| | - Hyeong-Jin Kim
- Department of Chemistry, Occidental College, 1600 Campus Rd, Los Angeles, CA 90041, USA.
| | - Ryan J Taylor
- Department of Chemistry, State University of New York at New Paltz, 1 Hawk Drive, New Paltz, NY 12561, USA.
| | - Nicholas Thomas
- Department of Chemistry, Occidental College, 1600 Campus Rd, Los Angeles, CA 90041, USA.
| | - Michael B Wengen
- Department of Chemistry, State University of New York at New Paltz, 1 Hawk Drive, New Paltz, NY 12561, USA.
| | - Nathan F Dalleska
- Environmental Analysis Center, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125, USA.
| | - Joseph P Bromley
- Department of Chemistry, State University of New York at New Paltz, 1 Hawk Drive, New Paltz, NY 12561, USA.
| | - Kimberly H Schermerhorn
- Department of Chemistry, State University of New York at New Paltz, 1 Hawk Drive, New Paltz, NY 12561, USA.
| | - Megan A Ferguson
- Department of Chemistry, State University of New York at New Paltz, 1 Hawk Drive, New Paltz, NY 12561, USA.
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Madin EMP, Dill LM, Ridlon AD, Heithaus MR, Warner RR. Human activities change marine ecosystems by altering predation risk. Glob Chang Biol 2016; 22:44-60. [PMID: 26448058 DOI: 10.1111/gcb.13083] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Revised: 08/28/2015] [Accepted: 08/29/2015] [Indexed: 06/05/2023]
Abstract
In ocean ecosystems, many of the changes in predation risk - both increases and decreases - are human-induced. These changes are occurring at scales ranging from global to local and across variable temporal scales. Indirect, risk-based effects of human activity are known to be important in structuring some terrestrial ecosystems, but these impacts have largely been neglected in oceans. Here, we synthesize existing literature and data to explore multiple lines of evidence that collectively suggest diverse human activities are changing marine ecosystems, including carbon storage capacity, in myriad ways by altering predation risk. We provide novel, compelling evidence that at least one key human activity, overfishing, can lead to distinct, cascading risk effects in natural ecosystems whose magnitude exceeds that of presumed lethal effects and may account for previously unexplained findings. We further discuss the conservation implications of human-caused indirect risk effects. Finally, we provide a predictive framework for when human alterations of risk in oceans should lead to cascading effects and outline a prospectus for future research. Given the speed and extent with which human activities are altering marine risk landscapes, it is crucial that conservation and management policy considers the indirect effects of these activities in order to increase the likelihood of success and avoid unfortunate surprises.
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Affiliation(s)
- Elizabeth M P Madin
- Department of Biological Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Lawrence M Dill
- Evolutionary and Behavioural Ecology Research Group, Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
| | - April D Ridlon
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA, 93106, USA
| | - Michael R Heithaus
- Department of Biological Sciences, Florida International University, 3000 NE 151st Street, North Miami, FL, 33181, USA
| | - Robert R Warner
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA, 93106, USA
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Sinopoli M, Cattano C, Andaloro F, Sarà G, Butler CM, Gristina M. Influence of fish aggregating devices (FADs) on anti-predator behaviour within experimental mesocosms. Mar Environ Res 2015; 112:152-159. [PMID: 26525872 DOI: 10.1016/j.marenvres.2015.10.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 10/19/2015] [Accepted: 10/21/2015] [Indexed: 06/05/2023]
Abstract
Commercial fishers have used fish aggregating devices throughout the Mediterranean Sea for over 40 years. These devices attract numerous predatory and forage species in both coastal and offshore environments. This study examined the influence of fish aggregating devices on schooling and aggregating behaviour by small forage fish in quasi-natural mesocosms. Anti-predator behaviour was evaluated for juvenile Caranx crysos under a variety of treatment conditions. Results suggest that, in the absence of physical structure, C. crysos first respond to a predatory threat by forming a school. When a physical structure is present, however, C. crysos show an occasional tendency to aggregate near the structure. These results suggest that a threatened prey species can change their defensive strategy against predatory behaviour. Further examination is required to explain if fish aggregating devices can increase survival rates of post-larval and juvenile prey species in the southern Mediterranean Sea. Management agencies should consider the relationship between the use of fish aggregating devices by commercial fisheries and the potential influence such devices possess on population dynamics of aggregating fish species.
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Affiliation(s)
- Mauro Sinopoli
- Italian Institute for Environmental Protection and Research (ISPRA), Palermo, Italy c/o Residence Marbela, Via Salvatore Puglisi 9, 98143 Palermo, Italy.
| | - Carlo Cattano
- Institute for Coastal Marine Environment (IAMC), CNR, Via L. Vaccara, 61, 91142 Mazara Del Vallo, TP, Italy; Dipartimento di Scienze Della Terra e Del Mare, University of Palermo, Viale Delle Scienze Ed. 16, 90128 Palermo, Italy.
| | - Franco Andaloro
- Italian Institute for Environmental Protection and Research (ISPRA), Palermo, Italy c/o Residence Marbela, Via Salvatore Puglisi 9, 98143 Palermo, Italy.
| | - Gianluca Sarà
- Dipartimento di Scienze Della Terra e Del Mare, University of Palermo, Viale Delle Scienze Ed. 16, 90128 Palermo, Italy.
| | - Christopher M Butler
- The University of Southern Mississippi, Gulf Coast Research Laboratory, 703 E. Beach Dr., Ocean Springs, MS 39564, USA.
| | - Michele Gristina
- Institute for Coastal Marine Environment (IAMC), CNR, Via L. Vaccara, 61, 91142 Mazara Del Vallo, TP, Italy.
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Brodin T, Johansson F. Effects of predator-induced thinning and activity changes on life history in a damselfly. Oecologia 2002; 132:316-322. [PMID: 28547367 DOI: 10.1007/s00442-002-0938-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2002] [Accepted: 04/06/2002] [Indexed: 11/29/2022]
Abstract
We investigated how the lethal and non-lethal presence and absence of a fish predator, perch (Perca fluviatils), influenced behaviour, numbers emerging, size at emergence, and development rate of the damselfly Lestes sponsa. The experiment was carried out in outdoor artificial ponds and spanned from the egg stage to emergence of the damselflies. During the experiment food resources for the damselflies were continuously monitored. Damselflies exposed to a lethal predator showed a significantly lower activity level than those in the absence of predators or subjected to a non-lethal predator. Half-way through the larval stage the reduction in activity level was correlated with the presence of lethal predators, and at the end of the larval stage with higher zooplankton densities. Though larvae decreased activity level, size at emergence was larger and development time faster for individuals in the lethal predator treatment. Since fewer larvae emerged from that treatment we interpret the larger size at emergence to be an effect of a combination of thinning and higher zooplankton densities.
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Affiliation(s)
- Tomas Brodin
- Animal Ecology, Department of Ecology and Environmental Science, Umeå University, 90187, Umeå.
| | - Frank Johansson
- Animal Ecology, Department of Ecology and Environmental Science, Umeå University, 90187, Umeå
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Abstract
We investigated the fitness and community consequences of behavioural interactions with multiple predators in a four-trophic-level system. We conducted an experiment in oval flow-through artificial-stream tanks to examine the single and interactive sublethal effects of brook trout and stoneflies on the size at emergence of Baetis bicaudatus (Ephemeroptera: Baetidae), and the cascading trophic effects on algal biomass, the food resource of the mayflies. No predation was allowed in the experiment, so that all effects were mediated through predator modifications of prey behaviour. We reared trout stream Baetis larvae from just before egg development until emergence in tanks with four treatments: (1) water from a holding tank with two brook trout (trout odour), (2) no trout odour + eight stoneflies with glued mouthparts, (3) trout odour + stoneflies and (4) no trout odour or stoneflies. We ended the experiment after 3 weeks when ten male and ten female subimagos had emerged from each tank, measured the size of ten male and ten female mature nymphs (with black wing pads), and collected algal samples from rocks at six locations in each tank. To determine the mechanism responsible for sublethal and cascading effects on lower trophic levels we made day and night observations of mayfly behaviour for the first 6 days by counting mayflies drifting in the water column and visible on natural substrata in the artificial streams. Trout odour and stoneflies similarly reduced the size of male and female Baetis emerging from artificial streams, with non-additive effects of both predators. While smaller females are less fecund, a fitness cost of small male size has not been determined. The mechanism causing sublethal effects on Baetis differed between predators. While trout stream Baetis retained their nocturnal periodicity in all treatments, stoneflies increased drift dispersal of mayflies at night, and trout suppressed night-time feeding and drift of mayflies. Stoneflies had less effect on Baetis behaviour when fish odour was present. Thus, we attribute the non-additivity of effects of fish and stoneflies on mayfly growth to an interaction modification whereby trout odour reduced the impact of stoneflies on Baetis behaviour. Since stonefly activity was also reduced in the presence of fish odour, this modification may be attributed to the effect of fish odour on stonefly behaviour. Only stoneflies delayed Baetis emergence, suggesting that stoneflies had a greater sublethal effect on Baetis fitness than did trout. Delayed emergence may reduce Baetis fitness by increasing risks of predation and parasitism on larvae, and increasing competition for mates or oviposition sites among adults. Finally, algal biomass was higher in tanks with both predators than in the other three treatments. These data implicate a behavioural trophic cascade because predators were not allowed to consume prey. Therefore, differences in algal biomass were attributed to predator-induced changes in mayfly behaviour. Our study demonstrates the importance of considering multiple predators when measuring direct sublethal effects of predators on prey fitness and indirect effects on lower trophic levels. Identification of an interaction modification illustrates the value of obtaining detailed information on behavioural mechanisms as an aid to understanding the complex interactions occurring among components of ecological communities.
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Affiliation(s)
- Barbara L Peckarsky
- Department of Entomology, Cornell University, Ithaca, NY 14853, USA e-mail: , , , , , , US
| | - Angus R McIntosh
- Rocky Mountain Biological Laboratory, P. O. Box 519, Crested Butte, CO 81224, USA, , , , , , US
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Nilsson PA, Brönmark C, Pettersson LB. Benefits of a predtor-induced morphology in crucian carp. Oecologia 1995; 104:291-296. [PMID: 28307584 DOI: 10.1007/bf00328363] [Citation(s) in RCA: 118] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/1995] [Accepted: 05/29/1995] [Indexed: 11/24/2022]
Abstract
Crucian carp (Carassius carassius) develop a deeper body in response to chemical cues from piscivores. This change in body morphology has been suggested to be a predator-induced defence. Here we investigate the possible benefits of the induced body morphology in laboratory experiments. Pike foraging behaviour when feeding on crucian carp of different body depths was recorded using video. Further, in a preference experiment pike were allowed to choose between shallow-bodied and deep-bodied crucian carp of similar lengths. Crucian carp body morphology did not affect predatory behaviours (activity, searching, following, observing, capture success) in northern pike, but an increase in crucian carp body depth led to an increase in handling time in pike. In the preference experiment, pike preferred shallow-bodied crucian carp over deep-bodied. Thus, a change in body morphology, induced by the presence of piscivores, benefits crucian carp by increasing piscivore handling times and an avoidance of the deep-bodied phenotype.
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Affiliation(s)
- P Anders Nilsson
- Department of Ecology, Lund University, Ecology Building, S-223 62, Lund, Sweden.
| | - Christer Brönmark
- Department of Ecology, Lund University, Ecology Building, S-223 62, Lund, Sweden
| | - Lars B Pettersson
- Department of Ecology, Lund University, Ecology Building, S-223 62, Lund, Sweden
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Witman JD, Sebens KP. Regional variation in fish predation intensity: a historical perspective in the Gulf of Maine. Oecologia 1992; 90:305-15. [PMID: 28313516 DOI: 10.1007/BF00317686] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/1991] [Accepted: 01/10/1992] [Indexed: 10/26/2022]
Abstract
Regional variation in the intensity of fish predation on tethered brittle stars and crabs was measured at 30-33 m depths in the rocky subtidal zone at seven sites representing coastal and offshore regions of the Gulf of Maine, USA. Analysis of covariance comparing the slopes of brittle star survivorship curves followed by multiple comparisons tests revealed five groupings of sites, with significantly greater predation rates in the two offshore than in the three coastal groups. Brittle stars tethered at the three offshore sites were consumed primarily by cod, Gadus morhua, with 60-100% prey mortality occuring in 2.5 h. In striking contrast, only 6-28% of brittle star prey was consumed in the same amount of time at the four coastal sites, which were dominated by cunner, Tautogolabrus adspersus. In several coastal trials, a majority of brittle star prey remained after 24 h. The pattern of higher predation offshore held for rock crabs as well with only 2.7% of tethered crabs consumed (n=36) at coastal sites versus 57.8% of crabs (n=64) consumed at offshore sites. Another important predatory fish, the wolffish, Anarhichas lupus, consumed more tethered crabs than brittle stars. Videos and time-lapse movies indicated that cod and wolffish were significantly more abundant at offshore than at coastal sites. Three hundred years of fishing pressure in New England has severely depleted stocks of at least one important benthic predator, the cod, in coastal waters. We speculate that this human-induced predator removal has lowered predation pressure on crabs and other large mobile epibenthos in deep coastal communities. Transect data indicate that coastal sites with few cod support significantly higher densities of crabs than offshore sites with abundant cod.
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