1
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Verschut TA, Ng R, Doubovetzky NP, Le Calvez G, Sneep JL, Minnaard AJ, Su CY, Carlsson MA, Wertheim B, Billeter JC. Aggregation pheromones have a non-linear effect on oviposition behavior in Drosophila melanogaster. Nat Commun 2023; 14:1544. [PMID: 36941252 PMCID: PMC10027874 DOI: 10.1038/s41467-023-37046-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 02/28/2023] [Indexed: 03/23/2023] Open
Abstract
Female fruit flies (Drosophila melanogaster) oviposit at communal sites where the larvae may cooperate or compete for resources depending on group size. This offers a model system to determine how females assess quantitative social information. We show that the concentration of pheromones found on a substrate increases linearly with the number of adult flies that have visited that site. Females prefer oviposition sites with pheromone concentrations corresponding to an intermediate number of previous visitors, whereas sites with low or high concentrations are unattractive. This dose-dependent decision is based on a blend of 11-cis-Vaccenyl Acetate (cVA) indicating the number of previous visitors and heptanal (a novel pheromone deriving from the oxidation of 7-Tricosene), which acts as a dose-independent co-factor. This response is mediated by detection of cVA by odorant receptor neurons Or67d and Or65a, and at least five different odorant receptor neurons for heptanal. Our results identify a mechanism allowing individuals to transform a linear increase of pheromones into a non-linear behavioral response.
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Affiliation(s)
- Thomas A Verschut
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
- Department of Zoology, Stockholm University, 106 91, Stockholm, Sweden
| | - Renny Ng
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Nicolas P Doubovetzky
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Guillaume Le Calvez
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Jan L Sneep
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Adriaan J Minnaard
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Chih-Ying Su
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Mikael A Carlsson
- Department of Zoology, Stockholm University, 106 91, Stockholm, Sweden
| | - Bregje Wertheim
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Jean-Christophe Billeter
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands.
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2
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Chartois M, Mesmin X, Quiquerez I, Borgomano S, Farigoule P, Pierre É, Thuillier JM, Streito JC, Casabianca F, Hugot L, Rossi JP, Rasplus JY, Cruaud A. Environmental factors driving the abundance of Philaenus spumarius in mesomediterranean habitats of Corsica (France). Sci Rep 2023; 13:1901. [PMID: 36732346 PMCID: PMC9893205 DOI: 10.1038/s41598-023-28601-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 01/20/2023] [Indexed: 02/04/2023] Open
Abstract
Philaenus spumarius (Ps) is considered the main insect vector of the bacterium Xylella fastidiosa (Xf) in Europe. As such, it is a key actor of the Xf pathosystem on which surveillance and management strategies could be implemented. Although research effort has increased in the past years, the ecological factors shaping Ps abundance and distribution across landscapes are still poorly known in most regions of Europe. We selected 64 plots of 500m2 in Corsican semi-natural habitats in which we sampled nymphs and adults of Ps during three years. While local or surrounding vegetation structure (low or high scrubland) had little effect on Ps abundance, we highlighted a positive relationship between Ps abundance and the density of Cistus monspeliensis in the plots. We also found larger populations of Ps in cooler and moister plots. The pattern of host association highlighted here is unique, which calls for more studies on the ecology of Ps in Europe, to help designing surveillance and management strategy for Xf.
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Affiliation(s)
- Marguerite Chartois
- CBGP, INRAE, CIRAD, IRD, Institut Agro, Univ Montpellier, Montpellier, France. .,AGAP, INRAE, CIRAD, Institut Agro, Univ Montpellier, San Giuliano, France.
| | - Xavier Mesmin
- CBGP, INRAE, CIRAD, IRD, Institut Agro, Univ Montpellier, Montpellier, France.,AGAP, INRAE, CIRAD, Institut Agro, Univ Montpellier, San Giuliano, France
| | - Ileana Quiquerez
- Conservatoire Botanique National de Corse, Office de l'Environnement de la Corse, Corte, France
| | - Sabrina Borgomano
- Conservatoire Botanique National de Corse, Office de l'Environnement de la Corse, Corte, France
| | - Pauline Farigoule
- CBGP, INRAE, CIRAD, IRD, Institut Agro, Univ Montpellier, Montpellier, France.,AgroParisTech, Paris, France
| | - Éric Pierre
- CBGP, INRAE, CIRAD, IRD, Institut Agro, Univ Montpellier, Montpellier, France
| | - Jean-Marc Thuillier
- CBGP, INRAE, CIRAD, IRD, Institut Agro, Univ Montpellier, Montpellier, France
| | - Jean-Claude Streito
- CBGP, INRAE, CIRAD, IRD, Institut Agro, Univ Montpellier, Montpellier, France
| | | | - Laetitia Hugot
- Conservatoire Botanique National de Corse, Office de l'Environnement de la Corse, Corte, France
| | - Jean-Pierre Rossi
- CBGP, INRAE, CIRAD, IRD, Institut Agro, Univ Montpellier, Montpellier, France
| | - Jean-Yves Rasplus
- CBGP, INRAE, CIRAD, IRD, Institut Agro, Univ Montpellier, Montpellier, France
| | - Astrid Cruaud
- CBGP, INRAE, CIRAD, IRD, Institut Agro, Univ Montpellier, Montpellier, France
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3
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Grilli MP, Bruno M, Fachinetti R. Quantification of the effect of host patch configuration on the abundance of Bemisia tabaci in central Argentina: a multimodel inference approach. BULLETIN OF ENTOMOLOGICAL RESEARCH 2023; 113:63-71. [PMID: 35899975 DOI: 10.1017/s0007485322000311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Bemisia tabaci is a complex of species, which is considered the most common and important pest of a wide range of crops belonging to many different botanical families. In Argentina, this species is recognized as a vector of geminiviruses, and Middle East-Asia Minor 1, Mediterranean, New World and New World 2 have been found to coexist in the same area. Landscape elements, like habitat patch area and isolation, define the habitat configuration and have a direct effect on insect populations between and within host patches. In this paper, we analyse the effect of potato patch configuration on the distribution and abundance of B. tabaci. Potato patches were identified using Landsat TM5 and TM7 images, and a supervised classification was performed to quantify the spatial distribution of the patches in the whole study area. Potato patch metrics were estimated using Fragstats 4.4. Generalized linear mixed models were employed to analyse the relationship between whiteflies and landscape configuration, through a multimodel inference approach, finding that B. tabaci abundance and landscape metrics were very variable. After a multimodel selection process, we found that perimeter-to-area ratio and Euclidean distance between patches were the variables that best explained whitefly abundance in potato patches. Implications of these findings are discussed.
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Affiliation(s)
- Mariano P Grilli
- Centro de Relevamiento y Evaluación de Recursos Agrícolas y Naturales (CREAN-IMBIV), CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina
- Cátedra de Bioestadística I y II, FCEFyN, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Marina Bruno
- Cátedra de Microbiología, Facultad de Ciencias Agropecuarias, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Romina Fachinetti
- Centro de Relevamiento y Evaluación de Recursos Agrícolas y Naturales (CREAN-IMBIV), CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina
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4
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Arends BR, Reisig DD, Gundry S, Greene JK, Kennedy GG, Reay‐Jones FP, Huseth AS. Helicoverpa zea (Lepidoptera: Noctuidae) feeding incidence and survival on Bt maize in relation to maize in the landscape. PEST MANAGEMENT SCIENCE 2022; 78:2309-2315. [PMID: 35233922 PMCID: PMC9310716 DOI: 10.1002/ps.6855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 02/23/2022] [Accepted: 03/02/2022] [Indexed: 05/12/2023]
Abstract
BACKGROUND Characterizing Helicoverpa zea (Boddie) damage to maize (Zea mays L.) in relation to the spatiotemporal composition of Bt crops is essential to understand how landscape composition affects H. zea abundance. To examine this relationship, paired Bt (expressing Cry1A.105 + Cry2Ab2) and non-Bt maize plots were sampled across North and South Carolina during 2017-2019. Kernel damage and larval exit holes were measured following larval development. To understand how maize abundance surrounding sample sites related to feeding damage and larval development, we quantified maize abundance in a 1 km buffer surrounding the sample site and examined the relationship between local maize abundance and kernel damage and larval exit holes. RESULTS Across the years and locations, damage in Bt maize was widespread but significantly lower than in non-Bt maize, indicating that despite the widespread occurrence of resistance to Cry toxins in maize, Bt maize still provides a measurable reduction in damage. There were negative relationships between kernel injury and ears with larval exit holes in both Bt and non-Bt maize and the proportion of maize in the landscape during the current year. CONCLUSION Despite the widespread occurrence of resistance to Cry toxins in maize, this resistance is incomplete, and on average Bt maize continues to provide a measurable reduction in damage. We interpret the negative relationship between abundance of maize within 1 km of the sample location and maize infestation levels, as measured by kernel damage and larval exit holes, to reflect dispersion of the ovipositing moth population over available maize within the local landscape. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
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Affiliation(s)
- Benjamin R. Arends
- Department of Entomology and Plant PathologyNorth Carolina State UniversityPlymouthNCUSA
| | - Dominic D. Reisig
- Department of Entomology and Plant PathologyNorth Carolina State UniversityPlymouthNCUSA
| | - Shawnee Gundry
- Department of Entomology and Plant PathologyNorth Carolina State UniversityPlymouthNCUSA
| | - Jeremy K. Greene
- Department of Plant and Environmental SciencesClemson University, Edisto Research and Education CenterBlackvilleSCUSA
| | - George G. Kennedy
- Department of Entomology and Plant PathologyNorth Carolina State UniversityRaleighNCUSA
| | - Francis P.F. Reay‐Jones
- Department of Plant and Environmental SciencesClemson University, Pee Dee Research and Education CenterFlorenceSCUSA
| | - Anders S. Huseth
- Department of Entomology and Plant PathologyNorth Carolina State UniversityPlymouthNCUSA
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5
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McLain DK, Pratt AE. The opportunity for and intensity of sexual selection in a seed bug depend on host plant dispersion. ETHOL ECOL EVOL 2022. [DOI: 10.1080/03949370.2021.2024267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Denson K. McLain
- Department of Biological Sciences, Georgia Southern University, P.O. Box 8042, Statesboro, GA 30460, USA
| | - Ann E. Pratt
- Department of Biological Sciences, Georgia Southern University, P.O. Box 8042, Statesboro, GA 30460, USA
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6
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Cohen H, Philpott SM, Liere H, Lin BB, Jha S. The relationship between pollinator community and pollination services is mediated by floral abundance in urban landscapes. Urban Ecosyst 2020. [DOI: 10.1007/s11252-020-01024-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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7
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Merwin AC, Inouye BD, Underwood N. Natal-habitat experience mediates the relationship between insect and hostplant densities. Oecologia 2020; 193:261-271. [PMID: 32281030 DOI: 10.1007/s00442-020-04639-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 03/30/2020] [Indexed: 11/26/2022]
Abstract
For some animals, the habitat which they first experience can influence the type of habitat which they select later in life and, thus, potentially their population distribution and dynamics. However, for many insect herbivores, whose natal habitat may consist of a single hostplant, the consequences of natal hostplant experience remain untested in landscapes relevant to the adult, which may select not only among plants, but among plant patches. As a first step towards understanding how natal hostplant experience shapes patterns of insect feeding damage in landscapes relevant to adults, we conducted partially caged field experiments with diamondback moths that were reared on either mustard or collard plants and then allowed to choose among and within patches of plants that varied in plant density and composition. We predicted that natal hostplant experience would interact with patch size and composition to influence the number of diamondback moth offspring and feeding damage per plant. As predicted, when moths were reared on collards, we found more offspring on and damage to collard plants in four-collard patches than in two-collard patches (i.e., resource concentration), but no difference when moths were reared on mustards. Contrary to predictions, we found no difference in the number of offspring on or damage to mixed plant patches compared with two- or four-collard plant patches regardless of natal hostplant type. Our research suggests that prior hostplant experience has complex consequences for how insects and their feeding damage are distributed in patchy environments and highlights the need for future research in this area.
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Affiliation(s)
- Andrew C Merwin
- Department of Biological Science, Florida State University, Tallahassee, FL, USA.
- Department of Biology and Geology, Baldwin Wallace University, Berea, OH, USA.
| | - Brian D Inouye
- Department of Biological Science, Florida State University, Tallahassee, FL, USA
| | - Nora Underwood
- Department of Biological Science, Florida State University, Tallahassee, FL, USA
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8
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Spatial and temporal patterns of a pulsed resource dynamically drive the distribution of specialist herbivores. Sci Rep 2019; 9:17787. [PMID: 31780724 PMCID: PMC6882897 DOI: 10.1038/s41598-019-54297-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 10/31/2019] [Indexed: 11/14/2022] Open
Abstract
Patterns and drivers of the spatio-temporal distribution of herbivores are key elements of their ecological and evolutionary impacts on plant populations. Herbivore spatial distributions may be influenced by increased (RCH: resource concentration hypothesis) or decreased (RDH: resource dilution hypothesis) resource densities, but the effect of temporal variations in resource densities on such distributions remains poorly documented. We used a survey of a masting tree species and its seed predators in Southeastern France to address the effect of a host’s pulsed resource on the spatio-temporal distributions of highly specialized insect herbivores feeding on seeds. Variations in both resource and seed predator densities were assessed by estimating seed production and seed infestation rates in focus trees during 10 consecutive years. We found increasing seed infestation rates with decreasing host tree densities in years of low seed production, indicating a RDH pattern of seed predators. However, such pattern was not persistent in years of high seed production during which seed infestation rates did not depend on host tree densities. We showed that temporal variations in resource density can lead to transience of seed predator spatial distribution. This study highlights how predictions of plant-herbivore interactions in natural ecosystems may rely on temporal components underlying RCH and RDH hypotheses.
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9
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Verschut TA, Carlsson MA, Hambäck PA. Scaling the interactive effects of attractive and repellent odours for insect search behaviour. Sci Rep 2019; 9:15309. [PMID: 31653955 PMCID: PMC6814803 DOI: 10.1038/s41598-019-51834-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 10/09/2019] [Indexed: 11/09/2022] Open
Abstract
Insects searching for resources are exposed to a complexity of mixed odours, often involving both attractant and repellent substances. Understanding how insects respond to this complexity of cues is crucial for understanding consumer-resource interactions, but also to develop novel tools to control harmful pests. To advance our understanding of insect responses to combinations of attractive and repellent odours, we formulated three qualitative hypotheses; the response-ratio hypothesis, the repellent-threshold hypothesis and the odour-modulation hypothesis. The hypotheses were tested by exposing Drosophila melanogaster in a wind tunnel to combinations of vinegar as attractant and four known repellents; benzaldehyde, 1-octen-3-ol, geosmin and phenol. The responses to benzaldehyde, 1-octen-3-ol and geosmin provided support for the response-ratio hypothesis, which assumes that the behavioural response depends on the ratio between attractants and repellents. The response to phenol, rather supported the repellent-threshold hypothesis, where aversion only occurs above a threshold concentration of the repellent due to overshadowing of the attractant. We hypothesize that the different responses may be connected to the localization of receptors, as receptors detecting phenol are located on the maxillary palps whereas receptors detecting the other odorants are located on the antennae.
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Affiliation(s)
- Thomas A Verschut
- Department of Ecology, Environment and Plant Sciences, Stockholm University, 106 91, Stockholm, Sweden. .,Department of Zoology, Stockholm University, 106 91, Stockholm, Sweden.
| | - Mikael A Carlsson
- Department of Zoology, Stockholm University, 106 91, Stockholm, Sweden
| | - Peter A Hambäck
- Department of Ecology, Environment and Plant Sciences, Stockholm University, 106 91, Stockholm, Sweden
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10
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Luquet M, Hullé M, Simon J, Parisey N, Buchard C, Jaloux B. Relative importance of long-term changes in climate and land-use on the phenology and abundance of legume crop specialist and generalist aphids. INSECT SCIENCE 2019; 26:881-896. [PMID: 29513406 PMCID: PMC7379299 DOI: 10.1111/1744-7917.12585] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 01/19/2018] [Accepted: 01/31/2018] [Indexed: 06/12/2023]
Abstract
Insect populations are prone to respond to global changes through shifts in phenology, distribution and abundance. However, global changes cover several factors such as climate and land-use, the relative importance of these being largely unknown. Here, we aim at disentangling the effects of climate, land-use, and geographical drivers on aphid abundance and phenology in France, at a regional scale and over the last 40 years. We used aerial data obtained from suction traps between 1978 and 2015 on five aphid species varying in their degree of specialization to legumes, along with climate, legume crop area and geographical data. Effects of environmental and geographical variables on aphid annual abundance and spring migration dates were analyzed using generalized linear mixed models. We found that within the last four decades, aphids have advanced their spring migration by a month, mostly due to the increase in temperature early in the year, and their abundance decreased by half on average, presumably in response to a combination of factors. The influence of legume crop area decreased with the degree of specialization of the aphid species to such crops. The effect of geographical variation was high even when controlling for environmental variables, suggesting that many other spatially structured processes act on aphid population characteristics. Multifactorial analyses helped to partition the effects of different global change drivers. Climate and land-use changes have strong effects on aphid populations, with important implications for future agriculture. Additionally, trait-based response variation could have major consequences at the community scale.
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Affiliation(s)
- Martin Luquet
- Agrocampus Ouest, Centre of Angers, Institute of GeneticsEnvironment and Plant Protection (IGEPP—Joint Research Unit 1349)AngersFrance
| | - Maurice Hullé
- INRA, Institute of GeneticsEnvironment and Plant Protection (IGEPP—Joint Research Unit 1349)Le RheuFrance
| | - Jean‐Christophe Simon
- INRA, Institute of GeneticsEnvironment and Plant Protection (IGEPP—Joint Research Unit 1349)Le RheuFrance
| | - Nicolas Parisey
- INRA, Institute of GeneticsEnvironment and Plant Protection (IGEPP—Joint Research Unit 1349)Le RheuFrance
| | - Christelle Buchard
- INRA, Institute of GeneticsEnvironment and Plant Protection (IGEPP—Joint Research Unit 1349)Le RheuFrance
| | - Bruno Jaloux
- Agrocampus Ouest, Centre of Angers, Institute of GeneticsEnvironment and Plant Protection (IGEPP—Joint Research Unit 1349)AngersFrance
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11
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Merwin AC, Underwood N, Inouye BD. Increased consumer density reduces the strength of neighborhood effects in a model system. Ecology 2018; 98:2904-2913. [PMID: 28869769 DOI: 10.1002/ecy.2004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 07/24/2017] [Accepted: 08/15/2017] [Indexed: 11/10/2022]
Abstract
An individual's susceptibility to attack can be influenced by conspecific and heterospecifics neighbors. Predicting how these neighborhood effects contribute to population-level processes such as competition and evolution requires an understanding of how the strength of neighborhood effects is modified by changes in the abundances of both consumers and neighboring resource species. We show for the first time that consumer density can interact with the density and frequency of neighboring organisms to determine the magnitude of neighborhood effects. We used the bean beetle, Callosobruchus maculatus, and two of its host beans, Vigna unguiculata and V. radiata, to perform a response-surface experiment with a range of resource densities and three consumer densities. At low beetle density, damage to beans was reduced with increasing conspecific density (i.e., resource dilution) and damage to the less preferred host, V. unguiculata, was reduced with increasing V. radiata frequency (i.e., frequency-dependent associational resistance). As beetle density increased, however, neighborhood effects were reduced; at the highest beetle densities neither focal nor neighboring resource density nor frequency influenced damage. These findings illustrate the importance of consumer density in mediating indirect effects among resources, and suggest that accounting for consumer density may improve our ability to predict population-level outcomes of neighborhood effects and our use of them in applications such as mixed-crop pest management.
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Affiliation(s)
- Andrew C Merwin
- Department of Biological Science, Florida State University, Tallahassee, Florida, 32306-4295, USA
| | - Nora Underwood
- Department of Biological Science, Florida State University, Tallahassee, Florida, 32306-4295, USA
| | - Brian D Inouye
- Department of Biological Science, Florida State University, Tallahassee, Florida, 32306-4295, USA
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12
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Castagneyrol B, Bonal D, Damien M, Jactel H, Meredieu C, Muiruri EW, Barbaro L. Bottom-up and top-down effects of tree species diversity on leaf insect herbivory. Ecol Evol 2017; 7:3520-3531. [PMID: 28515887 PMCID: PMC5433970 DOI: 10.1002/ece3.2950] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 02/21/2017] [Accepted: 03/07/2017] [Indexed: 12/02/2022] Open
Abstract
The diversity of plant neighbors commonly results in direct, bottom-up effects on herbivore ability to locate their host, and in indirect effects on herbivores involving changes in plant traits and a top-down control by their enemies. Yet, the relative contribution of bottom-up and top-down forces remains poorly understood. We also lack knowledge on the effect of abiotic constraints such as summer drought on the strength and direction of these effects. We measured leaf damage on pedunculate oak (Quercus robur), alone or associated with birch, pine or both in a long-term tree diversity experiment (ORPHEE), where half of the plots were irrigated while the other half remained without irrigation and received only rainfall. We tested three mechanisms likely to explain the effects of oak neighbors on herbivory: (1) Direct bottom-up effects of heterospecific neighbors on oak accessibility to herbivores, (2) indirect bottom-up effects of neighbors on the expression of leaf traits, and (3) top-down control of herbivores by predators. Insect herbivory increased during the growth season but was independent of neighbor identity and irrigation. Specific leaf area, leaf toughness, and thickness varied with neighbor identity while leaf dry matter content or C:N ratio did not. When summarized in a principal component analysis (PCA), neighbor identity explained 87% of variability in leaf traits. PCA axes partially predicted herbivory. Despite greater rates of attack on dummy caterpillars in irrigated plots, avian predation, and insect herbivory remained unrelated. Our study suggests that neighbor identity can indirectly influence insect herbivory in mixed forests by modifying leaf traits. However, we found only partial evidence for these trait-mediated effects and suggest that more attention should be paid to some unmeasured plant traits such as secondary metabolites, including volatile organic compounds, to better anticipate the effects of climate change on plant-insect interactions in the future.
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Affiliation(s)
| | - Damien Bonal
- EEFINRAUniversité de Lorraine54280ChampenouxFrance
| | - Maxime Damien
- ECOBIOUMR CNRS 6553Université de Rennes35042RennesFrance
| | | | | | - Evalyne W. Muiruri
- School of Biological SciencesRoyal Holloway University of LondonEghamSurrey TW20 0EXUK
- Department of BiosciencesDurham UniversityStockton Road, DurhamDH1 3LEUK
| | - Luc Barbaro
- BIOGECOINRAUniv. Bordeaux33610CestasFrance
- DynaforINPTEI PurpanINRAUniversité de Toulouse31320AuzevilleFrance
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13
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Stephan JG, Stenberg JA, Björkman C. Consumptive and nonconsumptive effect ratios depend on interaction between plant quality and hunting behavior of omnivorous predators. Ecol Evol 2017; 7:2327-2339. [PMID: 28405296 PMCID: PMC5383501 DOI: 10.1002/ece3.2828] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 12/30/2016] [Accepted: 01/03/2017] [Indexed: 12/05/2022] Open
Abstract
Predators not only consume prey but exert nonconsumptive effects in form of scaring, consequently disturbing feeding or reproduction. However, how alternative food sources and hunting mode interactively affect consumptive and nonconsumptive effects with implications for prey fitness have not been addressed, impending functional understanding of such tritrophic interactions. With a herbivorous beetle, two omnivorous predatory bugs (plant sap as alternative food, contrasting hunting modes), and four willow genotypes (contrasting suitability for beetle/omnivore), we investigated direct and indirect effects of plant quality on the beetles key reproductive traits (oviposition rate, clutch size). Using combinations of either or both omnivores on different plant genotypes, we calculated the contribution of consumptive (eggs predated) and nonconsumptive (fewer eggs laid) effect on beetle fitness, including a prey density‐independent measure (c:nc ratio). We found that larger clutches increase egg survival in presence of the omnivore not immediately consuming all eggs. However, rather than lowering mean, the beetles generally responded with a frequency shift toward smaller clutches. However, female beetles decreased mean and changed clutch size frequency with decreasing plant quality, therefore reducing intraspecific exploitative competition among larvae. More importantly, variation in host plant quality (to omnivore) led to nonconsumptive effects between one‐third and twice as strong as the consumptive effects. Increased egg consumption on plants less suitable to the omnivore may therefore be accompanied by less searching and disturbing the beetle, representing a “cost” to the indirect plant defense in the form of a lower nonconsumptive effect. Many predators are omnivores and altering c:nc ratios (with egg retention as the most direct link to prey fitness) via plant quality and hunting behavior should be fundamental to advance ecological theory and applications. Furthermore, exploring modulation of fitness traits by bottom‐up and top‐down effects will help to explain how and why species aggregate.
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Affiliation(s)
- Jörg G. Stephan
- Department of EcologySwedish University of Agricultural SciencesUppsalaSweden
| | - Johan A. Stenberg
- Department of Plant Protection BiologySwedish University of Agricultural SciencesAlnarpSweden
| | - Christer Björkman
- Department of EcologySwedish University of Agricultural SciencesUppsalaSweden
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14
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Abstract
Apparent feeding damage by insects on plants is often slight. Thus, the influences of insect herbivores on plant populations are likely minor. The role of insects on host-plant populations can be elucidated via several methods: stage-structured life tables of plant populations manipulated by herbivore exclusion and seed-addition experiments, tests of the enemy release hypothesis, studies of the effects of accidentally and intentionally introduced insect herbivores, and observations of the impacts of insect species that show outbreak population dynamics. These approaches demonstrate that some, but not all, insect herbivores influence plant population densities. At times, insect-feeding damage kills plants, but more often, it reduces plant size, growth, and seed production. Plant populations for which seed germination is site limited will not respond at the population level to reduced seed production. Insect herbivores can influence rare plant species and need to be considered in conservation programs. Alterations due to climate change in the distributions of insect herbivores indicate the possibility of new influences on host plants. Long-term studies are required to show if density-related insect behavior stabilizes plant populations or if environmental variation drives most temporal fluctuations in plant densities. Finally, insects can influence plant populations and communities through changing the diversity of nonhost species, modifying nutrient fluxes, and rejuvenating over mature forests.
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Affiliation(s)
- Judith H Myers
- Department of Zoology, University of British Columbia, Vancouver V6T 1Z4, British Columbia, Canada;
- Biodiversity Research Center, University of British Columbia, Vancouver V6T 1Z4, British Columbia, Canada
- Faculty of Land and Food Systems, University of British Columbia, Vancouver V6T 1Z4, British Columbia, Canada
| | - Rana M Sarfraz
- Department of Zoology, University of British Columbia, Vancouver V6T 1Z4, British Columbia, Canada;
- Biodiversity Research Center, University of British Columbia, Vancouver V6T 1Z4, British Columbia, Canada
- Faculty of Land and Food Systems, University of British Columbia, Vancouver V6T 1Z4, British Columbia, Canada
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15
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Wenninger A, Kim TN, Spiesman BJ, Gratton C. Contrasting Foraging Patterns: Testing Resource-Concentration and Dilution Effects with Pollinators and Seed Predators. INSECTS 2016; 7:E23. [PMID: 27271673 PMCID: PMC4931435 DOI: 10.3390/insects7020023] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 05/20/2016] [Accepted: 05/28/2016] [Indexed: 11/16/2022]
Abstract
Resource concentration effects occur when high resource density patches attract and support more foragers than low density patches. In contrast, resource dilution effects can occur if high density patches support fewer consumers. In this study, we examined the foraging rates of pollinators and seed predators on two perennial plant species (Rudbeckia triloba and Verbena stricta) as functions of resource density. Specifically, we examined whether resource-dense patches (densities of flower and seeds on individual plants) resulted in greater visitation and seed removal rates, respectively. We also examined whether foraging rates were context-dependent by conducting the study in two sites that varied in resource densities. For pollinators, we found negative relationships between the density of flowers per plant and visitation rates, suggesting dilution effects. For seed predators, we found positive relationships consistent with concentration effects. Saturation effects and differences in foraging behaviors might explain the opposite relationships; most of the seed predators were ants (recruitment-based foragers), and pollinators were mostly solitary foragers. We also found that foraging rates were site-dependent, possibly due to site-level differences in resource abundance and consumer densities. These results suggest that these two plant species may benefit from producing as many flowers as possible, given high levels of pollination and low seed predation.
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Affiliation(s)
- Alexandria Wenninger
- Great Lakes Bioenergy Research Center and Department of Entomology, University of Wisconsin-Madison, Madison, WI 53706, USA.
- Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK 99775, USA.
| | - Tania N Kim
- Great Lakes Bioenergy Research Center and Department of Entomology, University of Wisconsin-Madison, Madison, WI 53706, USA.
| | - Brian J Spiesman
- Great Lakes Bioenergy Research Center and Department of Entomology, University of Wisconsin-Madison, Madison, WI 53706, USA.
| | - Claudio Gratton
- Great Lakes Bioenergy Research Center and Department of Entomology, University of Wisconsin-Madison, Madison, WI 53706, USA.
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16
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Verschut TA, Becher PG, Anderson P, Hambäck PA. Disentangling associational effects: both resource density and resource frequency affect search behaviour in complex environments. Funct Ecol 2016. [DOI: 10.1111/1365-2435.12670] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Thomas A. Verschut
- Department of Ecology Environment and Plant Sciences Stockholm University 106 91 Stockholm Sweden
| | - Paul G. Becher
- Department of Plant Protection Biology Swedish University of Agricultural Sciences Box 102 230 53 Alnarp Sweden
| | - Peter Anderson
- Department of Plant Protection Biology Swedish University of Agricultural Sciences Box 102 230 53 Alnarp Sweden
| | - Peter A. Hambäck
- Department of Ecology Environment and Plant Sciences Stockholm University 106 91 Stockholm Sweden
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17
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Kärvemo S, Johansson V, Schroeder M, Ranius T. Local colonization‐extinction dynamics of a tree‐killing bark beetle during a large‐scale outbreak. Ecosphere 2016. [DOI: 10.1002/ecs2.1257] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- S. Kärvemo
- Department of EcologySwedish University of Agricultural Sciences Box 7044 750 07 Uppsala Sweden
| | - V. Johansson
- Department of EcologySwedish University of Agricultural Sciences Box 7044 750 07 Uppsala Sweden
| | - M. Schroeder
- Department of EcologySwedish University of Agricultural Sciences Box 7044 750 07 Uppsala Sweden
| | - T. Ranius
- Department of EcologySwedish University of Agricultural Sciences Box 7044 750 07 Uppsala Sweden
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18
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Gunton RM, Pöyry J. Scale‐specific spatial density dependence in parasitoids: a multi‐factor meta‐analysis. Funct Ecol 2016. [DOI: 10.1111/1365-2435.12627] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Juha Pöyry
- Natural Environment Centre Finnish Environment Institute (Syke) P.O. Box 140 FI‐00251 Helsinki Finland
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19
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Kos M, Bukovinszky T, Mulder PPJ, Bezemer TM. Disentangling above‐ and belowground neighbor effects on the growth, chemistry, and arthropod community on a focal plant. Ecology 2015; 96:164-75. [DOI: 10.1890/14-0563.1] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Martine Kos
- Netherlands Institute of Ecology (NIOO-KNAW), Department of Terrestrial Ecology, P.O. Box 50, 6700 AB, Wageningen, The Netherlands
| | - Tibor Bukovinszky
- Netherlands Institute of Ecology (NIOO-KNAW), Department of Terrestrial Ecology, P.O. Box 50, 6700 AB, Wageningen, The Netherlands
- Resource Ecology Group, Wageningen University, P.O. Box 47, 6700 AA, Wageningen, The Netherlands
| | - Patrick P. J. Mulder
- RIKILT-Wageningen UR, Wageningen University and Research Centre, P.O. Box 230, 6700 AE, Wageningen, The Netherlands
| | - T. Martijn Bezemer
- Netherlands Institute of Ecology (NIOO-KNAW), Department of Terrestrial Ecology, P.O. Box 50, 6700 AB, Wageningen, The Netherlands
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