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Ruberti N, Brundu G, Ceccherelli G, Grech D, Guala I, Loi B, Farina S. Intensive sea urchin harvest rescales Paracentrotus lividus population structure and threatens self-sustenance. PeerJ 2023; 11:e16220. [PMID: 38025682 PMCID: PMC10666612 DOI: 10.7717/peerj.16220] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 09/11/2023] [Indexed: 12/01/2023] Open
Abstract
The harvest of the edible sea urchin Paracentrotus lividus is intensively practiced in some regions of the Western Mediterranean Sea. The removal of the largest individuals can determine an overall reduction in population size and a size class truncation that can lead to a drastic drop the self-sustenance. The aim of this study is to evaluate the variability of the population reproductive potential across 5 years in one of the main harvest hotspots of Sardinia (Western Mediterranean Sea). The breeding stock consists of commercial and under-commercial size individuals which were sampled on a monthly basis to estimate their GonadoSomatic Index (GSI) and the Individual Gamete Output (IGO). In addition, the reproductive potential of the population-Total Gamete Output (TGO)-was calculated across the 5-year period in relation with the variation of the density of the breeding stock. During the last year, the reproductive potential was also estimated in a well-conserved population of a nearby Marine Protected Area. No significant variability in GSI and IGO was found over the 5 years nor when compared with the ones of protected population in the last year. However, the intensive harvest drastically rescaled the population body-size: although density of the commercial size class remained low, density of the under-commercial size-class halved from the beginning to the end of the study. Accordingly, the proportional decrease of their gamete output contribution led to a 40% loss of the reproductive potential of the whole population in the 5-year period. Interestingly, despite the loss of reproductive potential due to the decrease of the breeding stock density, the average values of IGO slightly increased across the years leading to the highest Annual Gamete Output (AGO) during the fourth year of sampling. This positive pattern could suggest a mechanism of reproductive investments of the survivors in terms of gonad production rate or increase in spawning intensity. This work provides evidence of the direct effect of size-selective harvesting on the rapid loss of population self-sustenance. Furthermore, it lays new prospective for future research of the indirect effects of the rescaling population body-size in functional traits of the sea urchin P. lividus and that could become important for both, sustainable exploitation and ecosystem conservation management.
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Affiliation(s)
- Nicole Ruberti
- Department of Architecture, Design and Planning, University of Sassari, Sassari, Italy
| | - Gianni Brundu
- IMC-International Marine Centre, Torre Grande (OR), Italy
| | - Giulia Ceccherelli
- Department of Chemical Physical Mathematical and Natural Science, University of Sassari, Sassari, Italy
- NBFC, National Biodiversity Future Center, Palermo, Italy
| | - Daniele Grech
- IMC-International Marine Centre, Torre Grande (OR), Italy
| | - Ivan Guala
- IMC-International Marine Centre, Torre Grande (OR), Italy
| | - Barbara Loi
- IMC-International Marine Centre, Torre Grande (OR), Italy
| | - Simone Farina
- Department of Integrative Marine Ecology (EMI), Stazione Zoologica Anton Dohrn–National Institute of Marine Biology, Ecology and Biotechnology, Genoa Marine Centre, Genoa, Italy
- National Research Council, Institute for the study of Anthropic Impacts and Sustainability in the Marine Environment (CNR-IAS), Torre Grande, Italy
- NBFC, National Biodiversity Future Center, Palermo, Italy
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Jarvis GC, Marshall DJ. Fertilization Mode Covaries with Body Size. Am Nat 2023; 202:448-457. [PMID: 37792921 DOI: 10.1086/725864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/06/2023]
Abstract
AbstractThe evolution of internal fertilization has occurred repeatedly and independently across the tree of life. As it has evolved, internal fertilization has reshaped sexual selection and the covariances among sexual traits, such as testes size, and gamete traits. But it is unclear whether fertilization mode also shows evolutionary associations with traits other than primary sex traits. Theory predicts that fertilization mode and body size should covary, but formal tests with phylogenetic control are lacking. We used a phylogenetically controlled approach to test the covariance between fertilization mode and adult body size (while accounting for latitude, offspring size, and offspring developmental mode) among 1,232 species of marine invertebrates from three phyla. Within all phyla, external fertilizers are consistently larger than internal fertilizers: the consequences of fertilization mode extend to traits that are only indirectly related to reproduction. We suspect that other traits may also coevolve with fertilization mode in ways that remain unexplored.
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Claereboudt EJS, Claereboudt MR, Savarino P, Caulier G, Gaumez L, Deleu M, Gerbaux P, Eeckhaut I. A Distinct Saponin Profile Drives an Olfactory-Mediated Aggregation in the Aquacultivated Sea Cucumber Holothuria scabra. Mar Drugs 2023; 21:184. [PMID: 36976233 PMCID: PMC10053547 DOI: 10.3390/md21030184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 03/13/2023] [Accepted: 03/13/2023] [Indexed: 03/19/2023] Open
Abstract
Intraspecific chemical communication between echinoderms has often been limited to prespawning aggregation. However, sea cucumber farmers have long observed year-round adult aggregation as a potential source of disease propagation and the suboptimal use of available sea pen acreage and food resources. In this study, through spatial distribution statistics, we demonstrated the significant aggregation of the aquacultivated sea cucumber Holothuria scabra both as adults in large sea-based pens and as juveniles in laboratory-based aquaria, proving that aggregation in these animals is not only observed during spawning. The role of chemical communication in aggregation was investigated using olfactory experimental assays. Our study established that the sediment that H. scabra feeds on as well as the water preconditioned by conspecifics induced positive chemotaxis in juvenile individuals. More specifically, through comparative mass spectrometry, a distinct triterpenoid saponin profile/mixture was identified to be a pheromone allowing sea cucumber intraspecific recognition and aggregation. This “attractive” profile was characterized as containing disaccharide saponins. This “attractive” aggregation-inducing saponin profile was, however, not conserved in starved individuals that were no longer attractive to other conspecifics. In summary, this study sheds new light on the pheromones in echinoderms. It highlights the complexity of the chemical signals detected by sea cucumbers and suggests a role of saponins well beyond that of a simple toxin.
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Burgess SC, Powell J, Bueno M. Dispersal, kin aggregation, and the fitness consequences of not spreading sibling larvae. Ecology 2023; 104:e3858. [PMID: 36059232 PMCID: PMC10078279 DOI: 10.1002/ecy.3858] [Citation(s) in RCA: 1] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Revised: 06/09/2022] [Accepted: 07/18/2022] [Indexed: 02/01/2023]
Abstract
Dispersal has far-reaching implications for individuals, populations, and communities, especially in sessile organisms. Escaping competition with conspecifics and with kin are theorized to be key factors leading to dispersal as an adaptation. However, manipulative approaches in systems in which adults are sessile but offspring have behaviors is required for a more complete understanding of how competition affects dispersal. Here, we integrate a series of experiments to study how dispersal affects the density and relatedness of neighbors, and how the density and relatedness of neighbors in turn affects fitness. In a marine bryozoan, we empirically estimated dispersal kernels and found that most larvae settled within ~1 m of the maternal colony, although some could potentially travel at least 10s of meters. Larvae neither actively preferred or avoided conspecifics or kin at settlement. We experimentally determined the effects of spreading sibling larvae by manipulating the density and relatedness of settlers and measuring components of fitness in the field. We found that settler density reduced maternal fitness when settler neighbors were siblings compared with when neighbors were unrelated or absent. Genetic markers also identified very few half sibs (and no full sibs) in adults from the natural population, and rarely close enough to directly interact. In this system, dispersal occurs over short distances (meters) yet, in contrast with expectations, there appears to be limited kinship between adult neighbors. Our results suggest that the limited dispersal increases early offspring mortality when siblings settle next to each other, rather than next to unrelated conspecifics, potentially reducing kinship in adult populations. High offspring production and multiple paternity could further dilute kinship at settlement and reduce selection for dispersal beyond the scale of 10s of meters.
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Affiliation(s)
- Scott C Burgess
- Department of Biological Science, Florida State University, Tallahassee, Florida, USA
| | - Jackson Powell
- Department of Biological Science, Florida State University, Tallahassee, Florida, USA
| | - Marília Bueno
- Department of Biological Science, Florida State University, Tallahassee, Florida, USA
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5
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Jönsson M, Morin M, Wang CK, Craik DJ, Degnan SM, Degnan BM. Sex-specific expression of pheromones and other signals in gravid starfish. BMC Biol 2022; 20:288. [PMID: 36528687 PMCID: PMC9759900 DOI: 10.1186/s12915-022-01491-0] [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] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 12/01/2022] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Many echinoderms form seasonal aggregations prior to spawning. In some fecund species, a spawning event can lead to population outbreaks with detrimental ecosystem impacts. For instance, outbreaks of crown-of-thorns starfish (COTS), a corallivore, can destroy coral reefs. Here, we examine the gene expression in gravid male and female COTS prior to spawning in the wild, to identify genome-encoded factors that may regulate aggregation and spawning. This study is informed by a previously identified exoproteome that attracts conspecifics. To capture the natural gene expression profiles, we isolated RNAs from gravid female and male COTS immediately after they were removed from the Great Barrier Reef. RESULTS: Sexually dimorphic gene expression is present in all seven somatic tissues and organs that we surveyed and in the gonads. Approximately 40% of the exoproteome transcripts are differentially expressed between sexes. Males uniquely upregulate an additional 68 secreted factors in their testes. A suite of neuropeptides in sensory organs, coelomocytes and gonads is differentially expressed between sexes, including the relaxin-like gonad-stimulating peptide and gonadotropin-releasing hormones. Female sensory tentacles-chemosensory organs at the distal tips of the starfish arms-uniquely upregulate diverse receptors and signalling molecules, including chemosensory G-protein-coupled receptors and several neuropeptides, including kisspeptin, SALMFamide and orexin. CONCLUSIONS Analysis of 103 tissue/organ transcriptomes from 13 wild COTS has revealed genes that are consistently differentially expressed between gravid females and males and that all tissues surveyed are sexually dimorphic at the molecular level. This finding is consistent with female and male COTS using sex-specific pheromones to regulate reproductive aggregations and synchronised spawning events. These pheromones appear to be received primarily by the sensory tentacles, which express a range of receptors and signalling molecules in a sex-specific manner. Furthermore, coelomocytes and gonads differentially express signalling and regulatory factors that control gametogenesis and spawning in other echinoderms.
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Affiliation(s)
- Mathias Jönsson
- grid.1003.20000 0000 9320 7537Centre for Marine Science, School of Biological Sciences, University of Queensland, Brisbane, QLD 4072 Australia
| | - Marie Morin
- grid.1003.20000 0000 9320 7537Centre for Marine Science, School of Biological Sciences, University of Queensland, Brisbane, QLD 4072 Australia
| | - Conan K. Wang
- grid.1003.20000 0000 9320 7537Institute for Molecular Bioscience, ARC Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, QLD 4072 Australia
| | - David J. Craik
- grid.1003.20000 0000 9320 7537Institute for Molecular Bioscience, ARC Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, QLD 4072 Australia
| | - Sandie M. Degnan
- grid.1003.20000 0000 9320 7537Centre for Marine Science, School of Biological Sciences, University of Queensland, Brisbane, QLD 4072 Australia
| | - Bernard M. Degnan
- grid.1003.20000 0000 9320 7537Centre for Marine Science, School of Biological Sciences, University of Queensland, Brisbane, QLD 4072 Australia
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Yu Y, Sun J, Chang Y, Zhao C. High fitness areas drive the aggregation of the sea urchin Mesocentrotus nudus. PeerJ 2022; 10:e12820. [PMID: 35111413 PMCID: PMC8783556 DOI: 10.7717/peerj.12820] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 12/30/2021] [Indexed: 01/10/2023] Open
Abstract
Sea urchin aggregation is a common phenomenon in coastlines. However, it remains controversial whether sea urchins form resource aggregations or behavioral aggregations in a non-spawning season. To clarify, we studied the aggregative responses to food and predators in the sea urchin Mesocentrotus nudus when high fitness areas (HFAs) were scarce versus sufficient. By taking the occupied area of each sea urchin (test diameter + spines = 4.5 cm) as a square (4.5 cm × 4.5 cm), we set scarce HFAs for the sea urchins in Experiment 1 (the squares of HFAs: the area occupied by experimental sea urchins = 1:1) and sufficient HFAs for the sea urchins in Experiment 2 (the squares of HFAs: the area occupied by experimental sea urchins = 2:1). If M. nudus form resource aggregations, they would aggregate passively under the scarce HFAs conditions, but not in the sufficient HFAs conditions. Conversely, if M. nudus form behavioral aggregation, aggregation would occur in both scarce and sufficient HFAs. The present results showed that in the scarce HFAs, M. nudus in the food and predator groups were significantly closer to the food and further from predators, and had significantly more aggregated numbers in HFAs than those in the control group. Sea urchins did not aggregate in response to food or predators under the sufficient HFAs, although significantly more sea urchins of the experimental group was found in HFAs than that of the control group. Sea urchins (at least M. nudus) form resource aggregations that are driven by the scarce HFAs. This provides valuable information into the mechanisms of the aggregation of sea urchins.
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Affiliation(s)
- Yushi Yu
- Dalian Ocean University, Key Laboratory of Mariculture & Stock Enhancement in North China’s Sea, Ministry of Agriculture and Rural Affairs, Dalian, Liaoning, China
| | - Jiangnan Sun
- Dalian Ocean University, Key Laboratory of Mariculture & Stock Enhancement in North China’s Sea, Ministry of Agriculture and Rural Affairs, Dalian, Liaoning, China
| | - Yaqing Chang
- Dalian Ocean University, Key Laboratory of Mariculture & Stock Enhancement in North China’s Sea, Ministry of Agriculture and Rural Affairs, Dalian, Liaoning, China
| | - Chong Zhao
- Dalian Ocean University, Key Laboratory of Mariculture & Stock Enhancement in North China’s Sea, Ministry of Agriculture and Rural Affairs, Dalian, Liaoning, China
- Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, China
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8
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Braje TJ, Bentz L. Bills of Fare, Consumer Demand, Social Status, Ethnicity, and the Collapse of California Abalone. J ETHNOBIOL 2021. [DOI: 10.2993/0278-0771-41.2.277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Todd J. Braje
- San Diego State University, Department of Anthropology, 5500 Campanile Drive, San Diego, CA 92182-6040
| | - Linda Bentz
- Chinese Historical Society of Southern California, 411 Bernard Street, Los Angeles, CA. 90012
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Henley EM, Quinn M, Bouwmeester J, Daly J, Zuchowicz N, Lager C, Bailey DW, Hagedorn M. Reproductive plasticity of Hawaiian Montipora corals following thermal stress. Sci Rep 2021; 11:12525. [PMID: 34108494 PMCID: PMC8190081 DOI: 10.1038/s41598-021-91030-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [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: 12/11/2020] [Accepted: 03/09/2021] [Indexed: 11/08/2022] Open
Abstract
Ocean warming, fueled by climate change, is the primary cause of coral bleaching events which are predicted to increase in frequency. Bleaching is generally damaging to coral reproduction, can be exacerbated by concomitant stressors like ultraviolet radiation (UVR), and can have lasting impacts to successful reproduction and potential adaptation. We compared morphological and physiological reproductive metrics (e.g., sperm motility, mitochondrial membrane integrity, egg volume, gametes per bundle, and fertilization and settlement success) of two Hawaiian Montipora corals after consecutive bleaching events in 2014 and 2015. Between the species, sperm motility and mitochondrial membrane potential had the most disparate results. Percent sperm motility in M. capitata, which declined to ~ 40% during bleaching from a normal range of 70-90%, was still less than 50% motile in 2017 and 2018 and had not fully recovered in 2019 (63% motile). By contrast, percent sperm motility in Montipora spp. was 86% and 74% in 2018 and 2019, respectively. This reduction in motility was correlated with damage to mitochondria in M. capitata but not Montipora spp. A major difference between these species is the physiological foundation of their UVR protection, and we hypothesize that UVR protective mechanisms inherent in Montipora spp. mitigate this reproductive damage.
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Affiliation(s)
- E Michael Henley
- Smithsonian Conservation Biology Institute, Front Royal, VA, USA.
- Hawai'i Institute of Marine Biology, University of Hawai'i at Mānoa, Kāne'ohe, HI, USA.
| | - Mariko Quinn
- Smithsonian Conservation Biology Institute, Front Royal, VA, USA
- Hawai'i Institute of Marine Biology, University of Hawai'i at Mānoa, Kāne'ohe, HI, USA
| | - Jessica Bouwmeester
- Smithsonian Conservation Biology Institute, Front Royal, VA, USA
- Hawai'i Institute of Marine Biology, University of Hawai'i at Mānoa, Kāne'ohe, HI, USA
| | - Jonathan Daly
- Smithsonian Conservation Biology Institute, Front Royal, VA, USA
- Hawai'i Institute of Marine Biology, University of Hawai'i at Mānoa, Kāne'ohe, HI, USA
| | - Nikolas Zuchowicz
- Smithsonian Conservation Biology Institute, Front Royal, VA, USA
- Hawai'i Institute of Marine Biology, University of Hawai'i at Mānoa, Kāne'ohe, HI, USA
| | - Claire Lager
- Smithsonian Conservation Biology Institute, Front Royal, VA, USA
- Hawai'i Institute of Marine Biology, University of Hawai'i at Mānoa, Kāne'ohe, HI, USA
| | - Daniel W Bailey
- Smithsonian Conservation Biology Institute, Front Royal, VA, USA
| | - Mary Hagedorn
- Smithsonian Conservation Biology Institute, Front Royal, VA, USA
- Hawai'i Institute of Marine Biology, University of Hawai'i at Mānoa, Kāne'ohe, HI, USA
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Farina S, Baroli M, Brundu R, Conforti A, Cucco A, De Falco G, Guala I, Guerzoni S, Massaro G, Quattrocchi G, Romagnoni G, Brambilla W. The challenge of managing the commercial harvesting of the sea urchin Paracentrotus lividus: advanced approaches are required. PeerJ 2020; 8:e10093. [PMID: 33083138 PMCID: PMC7548073 DOI: 10.7717/peerj.10093] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [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: 04/02/2020] [Accepted: 09/13/2020] [Indexed: 12/01/2022] Open
Abstract
Sea urchins act as a keystone herbivore in marine coastal ecosystems, regulating macrophyte density, which offers refuge for multiple species. In the Mediterranean Sea, both the sea urchin Paracentrotus lividus and fish preying on it are highly valuable target species for artisanal fisheries. As a consequence of the interactions between fish, sea urchins and macrophyte, fishing leads to trophic disorders with detrimental consequences for biodiversity and fisheries. In Sardinia (Western Mediterranean Sea), regulations for sea urchin harvesting have been in place since the mid 90s. However, given the important ecological role of P. lividus, the single-species fishery management may fail to take into account important ecosystem interactions. Hence, a deeper understanding of population dynamics, their dependance on environmental constraints and multispecies interactions may help to achieve long-term sustainable use of this resource. This work aims to highlight how sea urchin population structure varies spatially in relation to local environmental constraints and species interactions, with implications for their management. The study area (Sinis Peninsula, West Sardinia, Italy) that includes a Marine Reserve was divided into five sectors. These display combinations of the environmental constraints influencing sea urchin population dynamics, namely type of habitat (calcareous rock, granite, basalt, patchy and continuous meadows of Posidonia oceanica), average bottom current speed and predatory fish abundance. Size-frequency distribution of sea urchins under commercial size (<5 cm diameter size) assessed during the period from 2004 to 2007, before the population collapse in 2010, were compared for sectors and types of habitat. Specific correlations between recruits (0–1 cm diameter size) and bottom current speeds and between middle-sized sea urchins (2–5 cm diameter size) and predatory fish abundance were assessed. Parameters representing habitat spatial configuration (patch density, perimeter-to-area ratio, mean patch size, largest patch index, interspersion/juxtaposition index) were calculated and their influence on sea urchin density assessed. The density of sea urchins under commercial size was significantly higher in calcareous rock and was positively and significantly influenced by the density and average size of the rocky habitat patches. Recruits were significantly abundant in rocky habitats, while they were almost absent in P. oceanica meadows. The density of middle-sized sea urchins was more abundant in calcareous rock than in basalt, granite or P. oceanica. High densities of recruits resulted significantly correlated to low values of average bottom current speed, while a negative trend between the abundance of middle-sized sea urchins and predatory fish was found. Our results point out the need to account for the environmental constraints influencing local sea urchin density in fisheries management.
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Affiliation(s)
- Simone Farina
- IMC-International Marine Centre, Oristano, Italy.,Current Affiliation: Stazione Zoologica Anton Dohrn, Deptartment of Integrative Marine Ecology, Ischia Marine Centre, Ischia, Naples, Italy
| | - Maura Baroli
- IMC-International Marine Centre, Oristano, Italy
| | - Roberto Brundu
- Marine Protected Area "Penisola del Sinis-Isola di Mal di Ventre", Cabras, Oristano, Italy
| | - Alessandro Conforti
- CNR-IAS, National Research Council, Institute for the study of Anthropic impacts and Sustainability in the marine environment, Oristano, Italy
| | - Andrea Cucco
- CNR-IAS, National Research Council, Institute for the study of Anthropic impacts and Sustainability in the marine environment, Oristano, Italy
| | - Giovanni De Falco
- CNR-IAS, National Research Council, Institute for the study of Anthropic impacts and Sustainability in the marine environment, Oristano, Italy
| | - Ivan Guala
- IMC-International Marine Centre, Oristano, Italy
| | | | - Giorgio Massaro
- CNR-IAS, National Research Council, Institute for the study of Anthropic impacts and Sustainability in the marine environment, Oristano, Italy
| | - Giovanni Quattrocchi
- CNR-IAS, National Research Council, Institute for the study of Anthropic impacts and Sustainability in the marine environment, Oristano, Italy
| | - Giovanni Romagnoni
- COISPA Tecnologia & Ricerca, Bari, Italy.,Deptartment of Biosciences, University of Oslo, Centre for Ecological and Evolutionary Synthesis (CEES), Oslo, Norway
| | - Walter Brambilla
- CNR-IAS, National Research Council, Institute for the study of Anthropic impacts and Sustainability in the marine environment, Oristano, Italy
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11
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Matsumoto Y. Effects of mucus trail following on the distance between individuals of opposite sex and its influence on the evolution of the trait in the Ezo abalone Haliotis discus hannai. PeerJ 2020; 8:e8710. [PMID: 32195052 PMCID: PMC7069403 DOI: 10.7717/peerj.8710] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 02/07/2020] [Indexed: 11/20/2022] Open
Abstract
Background Aggregation affects the fertilization rate of species that utilize external fertilization. However, the process of aggregation has not been studied in detail, using either theoretical models or real world observations. We used the Ezo abalone Haliotis discus hannai as a model animal species to evaluate whether mucus trail following (MTF) facilitates aggregation by reducing the distance between members of opposite sexes. We also examined whether the fertilization rate increase with mucus-trail-following is an evolutionary driving force in mucus following behavior. Methods We used a y-maze to test whether H. discus hannai follows the mucus trails of other individuals. Distances between members of the opposite sex of MTF individuals were compared to non-MTF individuals using an individual-based model (IBM) consistent with the behavior of H. discus hannai. To examine whether MTF behavior evolved to reduce distances between members of the opposite sex, we constructed simple population genetic models of a diploid population with nonoverlapping, discrete generations. Results Haliotis discus hannai chose the y-maze arm with the mucus trail more frequently than the one without, regardless of the sex of the abalone that secreted the mucus or the reproductive season. In the IBM the distance between opposite sexes was significantly reduced by MTF behavior; however, the difference in distances between opposite sex compared to same sex individuals was only several centimeters. Simple population genetic models indicated that the aggregating effect of MTF between the opposite sex members could be an evolutionary driving force. Conclusions These results suggest that observed MTF behavior might have evolved as a mechanism to increase the fertilization rates although other factors could also be involved.
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Affiliation(s)
- Yukio Matsumoto
- Miyako Laboratory, Tohoku National Fisheries Research Institute, Japan Fisheries Research and Education Agency, Miyako, Iwate, Japan
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12
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Guerra V, Haynes G, Byrne M, Yasuda N, Adachi S, Nakamura M, Nakachi S, Hart MW. Nonspecific expression of fertilization genes in the crown-of-thorns Acanthaster cf. solaris: Unexpected evidence of hermaphroditism in a coral reef predator. Mol Ecol 2019; 29:363-379. [PMID: 31837059 DOI: 10.1111/mec.15332] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [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: 07/15/2019] [Revised: 11/28/2019] [Accepted: 12/10/2019] [Indexed: 01/04/2023]
Abstract
The characterization of gene expression in gametes has advanced our understanding of the molecular basis for ecological variation in reproductive success and the evolution of reproductive isolation. These advances are especially significant for ecologically important keystone predators such as the coral-eating crown-of-thorns sea stars (COTS, Acanthaster) which are the most influential predator species in Indo-Pacific coral reef ecosystems and the focus of intensive management efforts. We used RNA-seq and transcriptome assemblies to characterize the expression of genes in mature COTS gonads. We described the sequence and domain organization of eight genes with sex-specific expression and well known functions in fertilization in other echinoderms. We found unexpected expression of genes in one ovary transcriptome that are characteristic of males and sperm, including genes that encode the sperm-specific guanylate cyclase receptor for an egg pheromone, and the sperm acrosomal protein bindin. In a reassembly of previously published RNA-seq data from COTS testes, we found a complementary pattern: strong expression of four genes that are otherwise well known to encode egg-specific fertilization proteins, including the egg receptor for bindin (EBR1) and the acrosome reaction-inducing substance in the egg coat (ARIS1, ARIS2, ARIS3). We also found histological evidence of both eggs and sperm developing in the same gonad in several COTS individuals from a parallel study. These results suggest the occurrence of hermaphrodites, and the potential for reproductive assurance via self-fertilization. Our findings have implications for management of COTS populations, especially in consideration of the large size and massive fecundity of these sea stars.
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Affiliation(s)
- Vanessa Guerra
- Department of Biological Sciences, Simon Fraser University, Burnaby, BC, Canada.,Department of Invertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
| | - Gwilym Haynes
- Department of Biological Sciences, Simon Fraser University, Burnaby, BC, Canada.,Department of Biology, Langara College, Vancouver, British Columbia, Canada
| | - Maria Byrne
- Schools of Medical and Biological Sciences, The University of Sydney, Sydney, Australia
| | - Nina Yasuda
- Department of Marine Biology and Environmental Science, Faculty of Agriculture, University of Miyazaki, Miyazaki, Japan
| | - Souta Adachi
- School of Marine Science and Technology, Tokai University, Shimizu, Shizuoka, Japan
| | - Masako Nakamura
- School of Marine Science and Technology, Tokai University, Shimizu, Shizuoka, Japan
| | | | - Michael W Hart
- Department of Biological Sciences, Simon Fraser University, Burnaby, BC, Canada
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13
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Han Y, Shi W, Rong J, Zha S, Guan X, Sun H, Liu G. Exposure to Waterborne nTiO 2 Reduces Fertilization Success and Increases Polyspermy in a Bivalve Mollusc: A Threat to Population Recruitment. Environ Sci Technol 2019; 53:12754-12763. [PMID: 31596577 DOI: 10.1021/acs.est.9b03675] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Fertilization success is crucial for the population recruitment of an organism. However, little is known about the threat of nanoparticles (NPs) to the fertilization of broadcast spawners. Therefore, the effects of nTiO2 on fertilization success, polyspermy rate, sperm velocity, gametic DNA damage, sperm-egg collision probability, gamete fusion, and oocyte ultrastructure were investigated in a broadcast spawning bivalve, Tegillarca granosa. The results obtained show that fertilization success significantly decreased, whereas polyspermy risk markedly increased upon nTiO2 exposure. In addition, nTiO2 exposure led to a significant reduction in sperm swimming velocity, which would subsequently constrain gamete collisions. In addition, nTiO2 exposure resulted in a significant decline in gamete fusion per collision along with aggravated DNA damage in gametes. Furthermore, ultrastructural analysis illustrated the attachment of nTiO2 to the oocyte surface, which subsequently resulted in microvillus disassociation and plasma membrane damage. In conclusion, the results obtained suggest a significant threat from NP pollution to the recruitment of broadcast spawning invertebrates.
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Affiliation(s)
- Yu Han
- College of Animal Sciences , Zhejiang University , Hangzhou 310058 , China
| | - Wei Shi
- College of Animal Sciences , Zhejiang University , Hangzhou 310058 , China
| | - Jiahuan Rong
- College of Animal Sciences , Zhejiang University , Hangzhou 310058 , China
| | - Shanjie Zha
- College of Animal Sciences , Zhejiang University , Hangzhou 310058 , China
| | - Xiaofan Guan
- College of Animal Sciences , Zhejiang University , Hangzhou 310058 , China
| | - Hongxiang Sun
- College of Animal Sciences , Zhejiang University , Hangzhou 310058 , China
| | - Guangxu Liu
- College of Animal Sciences , Zhejiang University , Hangzhou 310058 , China
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14
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Abstract
The eastern oyster plays a vital role in estuarine habitats, acting as an ecosystem engineer and improving water quality. Populations of Chesapeake Bay oysters have declined precipitously in recent decades. The fossil record, which preserves 500 000 years of once-thriving reefs, provides a unique opportunity to study pristine reefs to establish a possible baseline for mitigation. For this study, over 900 fossil oysters were examined from three Pleistocene localities in the Chesapeake region. Data on oyster shell lengths, lifespans and population density were assessed. Comparisons to modern Crassostrea virginica, sampled from monitoring surveys of similar environments, reveal that fossil oysters were significantly larger, longer-lived and more abundant than modern oysters from polyhaline salinity zones. This pattern results from the preferential harvesting of larger, reproductively more active females from the modern population. These fossil data, combined with modern estimates of age-based fecundity and mortality, make it possible to estimate ecosystem services in these long-dead reefs, including filtering capacity, which was an order of magnitude greater in the past than today. Conservation palaeobiology can provide us with a picture of not just what the Chesapeake Bay looked like, but how it functioned, before humans. This article is part of a discussion meeting issue 'The past is a foreign country: how much can the fossil record actually inform conservation?'
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Affiliation(s)
- Rowan Lockwood
- Department of Geology, William and Mary, PO Box 8795, Williamsburg, VA 23187, USA
| | - Roger Mann
- Virginia Institute of Marine Science, William and Mary, Route 1208 Greate Road, Gloucester Point, VA 23062-1346, USA
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15
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Lenz B, Fogarty ND, Figueiredo J. Effects of ocean warming and acidification on fertilization success and early larval development in the green sea urchin Lytechinus variegatus. Mar Pollut Bull 2019; 141:70-78. [PMID: 30955782 DOI: 10.1016/j.marpolbul.2019.02.018] [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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 02/03/2019] [Accepted: 02/10/2019] [Indexed: 06/09/2023]
Abstract
Ocean acidification and warming are predicted to affect the early life of many marine organisms, but their effects can be synergistic or antagonistic. This study assessed the combined effects of near-future (2100) ocean acidification (pH 7.8) and warming (+3 °C) on the fertilization, larval development and growth of the green sea urchin, Lytechinus variegatus, common in tropical reefs of Florida and the Caribbean. Acidification had no effect on fertilization, but delayed larval development, stunted growth, and increased asymmetry. Warming decreased fertilization success when the sperm:egg ratio was higher (1847:1), accelerated larval development, but had no effect on growth. When exposed to both acidification and warming, fertilization rates decreased, larval development accelerated (due to increased respiration/metabolism), but larvae were smaller and more asymmetric, meaning acidification and warming had additive effects. Thus, climate change is expected to decrease the abundance of this important herbivore, exacerbating macroalgal growth and dominance on coral reefs.
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Affiliation(s)
- Brittney Lenz
- Department of Marine and Environmental Science, Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, Dania Beach, FL, USA
| | - Nicole D Fogarty
- Department of Marine and Environmental Science, Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, Dania Beach, FL, USA; Department of Biology and Marine Biology, University of North Carolina Wilmington, Center for Marine Science, USA
| | - Joana Figueiredo
- Department of Marine and Environmental Science, Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, Dania Beach, FL, USA.
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16
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Aalto EA, Micheli F, Boch CA, Espinoza Montes JA, Woodson CB, De Leo GA. Catastrophic Mortality, Allee Effects, and Marine Protected Areas. Am Nat 2019; 193:391-408. [DOI: 10.1086/701781] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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17
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Ferner MC, Hodin J, Ng G, Gaylord B. Brief exposure to intense turbulence induces a sustained life-history shift in echinoids. ACTA ACUST UNITED AC 2019; 222:jeb.187351. [PMID: 30573667 DOI: 10.1242/jeb.187351] [Citation(s) in RCA: 3] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 12/14/2018] [Indexed: 12/26/2022]
Abstract
In coastal ecosystems, attributes of fluid motion can prompt animal larvae to rise or sink in the water column and to select microhabitats within which they attach and commit to a benthic existence. In echinoid (sea urchin and sand dollar) larvae living along wave-exposed shorelines, intense turbulence characteristic of surf zones can cause individuals to undergo an abrupt life-history shift characterized by precocious entry into competence - the stage at which larvae will settle and complete metamorphosis in response to local cues. However, the mechanistic details of this turbulence-triggered onset of competence remain poorly defined. Here, we evaluate in a series of laboratory experiments the time course of this turbulence effect, both the rapidity with which it initiates and whether it perdures. We found that larvae become competent with turbulence exposures as brief as 30 s, with longer exposures inducing a greater proportion of larvae to become competent. Intriguingly, larvae can remember such exposures for a protracted period (at least 24 h), a pattern reminiscent of long-term potentiation. Turbulence also induces short-term behavioral responses that last less than 30 min, including cessation of swimming, that facilitate sinking and thus contact of echinoid larvae with the substratum. Together, these results yield a novel perspective on how larvae find their way to suitable adult habitat at the critical settlement transition, and also open new experimental opportunities to elucidate the mechanisms by which planktonic animals respond to fluid motion.
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Affiliation(s)
- Matthew C Ferner
- San Francisco Bay National Estuarine Research Reserve and Estuary & Ocean Science Center, San Francisco State University, Tiburon, CA 94920, USA
| | - Jason Hodin
- Friday Harbor Laboratories, University of Washington, Friday Harbor, WA 98250, USA
| | - Gabriel Ng
- Bodega Marine Laboratory and Department of Evolution and Ecology, University of California at Davis, Bodega Bay, CA 94923, USA
| | - Brian Gaylord
- Bodega Marine Laboratory and Department of Evolution and Ecology, University of California at Davis, Bodega Bay, CA 94923, USA
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18
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Hare RM, Simmons LW. Sexual selection and its evolutionary consequences in female animals. Biol Rev Camb Philos Soc 2018; 94:929-956. [DOI: 10.1111/brv.12484] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 10/31/2018] [Accepted: 11/02/2018] [Indexed: 01/01/2023]
Affiliation(s)
- Robin M. Hare
- Centre for Evolutionary Biology, School of Biological Sciences University of Western Australia 35 Stirling Highway, Perth, 6009 Australia
| | - Leigh W. Simmons
- Centre for Evolutionary Biology, School of Biological Sciences University of Western Australia 35 Stirling Highway, Perth, 6009 Australia
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Betters M, Levitan DR. The Role of Male Variation in Fertilization Success in Determining the Costs and Benefits of Polyandry in the Broadcast Spawning Urchin Lytechinus variegatus. Biol Bull 2018; 235:63-70. [PMID: 30358447 DOI: 10.1086/699406] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Although the benefits to males mating with multiple females have been well documented, the benefits to females mating with multiple males (polyandry) are less studied, particularly the mechanism that might drive these potential benefits. Benefits of polyandry might stem from increasing the chance of mating with a high-quality or compatible male or stem from the ability of multiple males to fertilize more eggs than any single male. We examine the fertilization consequences of polyandry in the sea urchin Lytechinus variegatus. This species has variation in spine color, and we conducted matings between individual and pooled sperm from two males that matched or mismatched in color. The results indicate that (1) males with white spines achieved higher fertilization and were more likely to cause polyspermy than males with purple spines, and there was no effect of female spine color on fertilization; (2) when comparing the average success of individual matings with pooled-sperm matings, there was a net benefit to polyandry when purple-spine males were pooled, a net cost when white-spine males were pooled, and no difference when mismatched spine color males were pooled; and (3) the success under pooled-sperm trials, with any of the spine color combinations, never exceeded the success of the more successful male in the individual-male trials. Together these results suggest that the consequences of polyandry depend on the relation between sperm availability and the sensitivity of eggs to sperm limitation and polyspermy with respect to the specific set of available males. The potential fertilization consequences of a female spawning with multiple males might be associated primarily with increasing the amount of sperm available to fertilize her eggs and secondarily with increasing the chances of mating with a higher-quality or more compatible male, as opposed to a diversity of males.
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20
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Bayer SR, Wahle RA, Brady DC, Jumars PA, Stokesbury KDE, Carey JD. Fertilization success in scallop aggregations: reconciling model predictions and field measurements of density effects. Ecosphere 2018. [DOI: 10.1002/ecs2.2359] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- S. R. Bayer
- Darling Marine Center University of Maine Walpole Maine 04573 USA
| | - R. A. Wahle
- Darling Marine Center University of Maine Walpole Maine 04573 USA
| | - D. C. Brady
- Darling Marine Center University of Maine Walpole Maine 04573 USA
| | - P. A. Jumars
- Darling Marine Center University of Maine Walpole Maine 04573 USA
| | - K. D. E. Stokesbury
- Department of Fisheries Oceanography School for Marine Science and Technology University of Massachusetts Dartmouth Fairhaven Massachusetts 02719 USA
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21
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Farina S, Quattrocchi G, Guala I, Cucco A. Hydrodynamic patterns favouring sea urchin recruitment in coastal areas: A Mediterranean study case. Mar Environ Res 2018; 139:182-192. [PMID: 29804786 DOI: 10.1016/j.marenvres.2018.05.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [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: 12/18/2017] [Revised: 05/04/2018] [Accepted: 05/07/2018] [Indexed: 05/21/2023]
Abstract
In invertebrate fisheries, sea urchin harvesting continues to grow with dramatic consequences for benthic ecosystems. The identification of areas with a marked natural recruitment and the mechanisms regulating it is crucial for the conservation of benthic communities and for planning the sustainable harvesting. This study evaluates the spatial distribution and density of recruits of the edible sea urchin Paracentrotus lividus along the Sinis + Peninsula (Sardinia) and explores its significant relationships with the local oceanographic features. Our results reveal that recruitment is favoured in areas with slow currents and high levels of confinement and trapping of the water masses. Analysis of the residual circulation indicates that the presence of local standing circulation structures promotes the sea urchin recruitment process. Our findings emphasize the importance of managing local sea urchin harvesting as a system of populations with their demographic influence mainly dependent on the most important ecological driver that is the recruitment.
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Affiliation(s)
- S Farina
- IMC - International Marine Centre, Loc. Sa Mardini, Torre Grande, 09170, Oristano, Italy.
| | - G Quattrocchi
- IAMC - Institute for Coastal Marine Environment, CNR - National Research Council of Italy, Loc. Sa Mardini, Torre Grande, 09170, Oristano, Italy
| | - I Guala
- IMC - International Marine Centre, Loc. Sa Mardini, Torre Grande, 09170, Oristano, Italy
| | - A Cucco
- IAMC - Institute for Coastal Marine Environment, CNR - National Research Council of Italy, Loc. Sa Mardini, Torre Grande, 09170, Oristano, Italy
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22
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Vieira EA, Flores AAV, Dias GM. Persistence and space preemption explain species-specific founder effects on the organization of marine sessile communities. Ecol Evol 2018; 8:3430-3442. [PMID: 29607036 PMCID: PMC5869360 DOI: 10.1002/ece3.3853] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [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: 09/27/2017] [Revised: 12/25/2017] [Accepted: 01/02/2018] [Indexed: 11/24/2022] Open
Abstract
Community assembly may not follow predictable successional stages, with a large fraction of the species pool constituted by potential pioneering species and successful founders defined through lottery. In such systems, priority effects may be relevant in the determination of trajectories of developing communities and hence diversity and assemblage structure at later advanced states. In order to assess how different founder species may trigger variable community trajectories and structures, we conducted an experimental study using subtidal sessile assemblages as model. We manipulated the identity of functionally different founders and initial colony size (a proxy of the time lag before the arrival of later species), and followed trajectories. We did not observe any effects of colony size on response variables, suggesting that priority effects take place even when the time lag between the establishment of pioneering species and late colonizers is very short. Late community structure at experimental panels that started either with the colonial ascidian Botrylloides nigrum, or the arborescent bryozoan Bugula neritina, was similar to control panels allowed natural assembling. In spite of high potential for fast space domination, and hence negative priority effects, B. nigrum suffered high mortality and did not persist throughout succession. Bugula neritina provided complex physical microhabitats through conspecific clustering that have enhanced larval settlement of late species arrivals, but no apparent facilitation was observed. Differently, panels founded by the encrusting bryozoan Schizoporella errata led to different and less diverse communities compared to naturally assembled panels, evidencing strong negative priority effects through higher persistence and space preemption. Schizoporella errata founder colonies inhibited further conspecific settlement, which may greatly relax intraspecific competition, allowing resource allocation to colony growth and space domination, thus reducing the chances for the establishment of other species.
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Affiliation(s)
- Edson A Vieira
- Programa de Pós-Graduação em Ecologia Instituto de Biologia Universidade Estadual de Campinas (UNICAMP) Campinas Brazil.,Centro de Biologia Marinha Universidade de São Paulo (USP) São Sebastião Brazil
| | - Augusto A V Flores
- Centro de Ciências Naturais e Humanas Universidade Federal do ABC (UFABC) São Bernardo do Campo Brazil
| | - Gustavo M Dias
- Centro de Biologia Marinha Universidade de São Paulo (USP) São Sebastião Brazil
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23
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Marquet N, Hubbard PC, da Silva JP, Afonso J, Canário AVM. Chemicals released by male sea cucumber mediate aggregation and spawning behaviours. Sci Rep 2018; 8:239. [PMID: 29321586 PMCID: PMC5762768 DOI: 10.1038/s41598-017-18655-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 12/14/2017] [Indexed: 11/09/2022] Open
Abstract
The importance of chemical communication in reproduction has been demonstrated in many marine broadcast spawners. However, little is known about the use of chemical communication by echinoderms, the nature of the compounds involved and their mechanism(s) of action. Here, the hypothesis that the sea cucumber Holothuria arguinensis uses chemical communication for aggregation and spawning was tested. Water conditioned by males, but not females, attracted both males and females; gonad homogenates and coelomic fluid had no effect on attraction. Male spawning water, but not female spawning water, stimulated males and females to release their gametes; the spermatozoa alone did not induce spawning. H. arguinensis male spawning water also induced spawning in the phylogenetically related H. mammata. This indicates that males release pheromones together with their gametes that induce spawning in conspecifics and possibly sympatric species. Finally, the male pheromone seems to be a mixture with at least one labile compound (biological activity is lost after four hours at ambient temperature) possibly including phosphatidylcholines. The identification of pheromones in sea cucumbers offers a new ecological perspective and may have practical applications for their aquaculture.
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Affiliation(s)
- Nathalie Marquet
- CCMAR-Centre of Marine Sciences, Universidade do Algarve, Campus de Gambelas, 8005-139, Faro, Portugal.
| | - Peter C Hubbard
- CCMAR-Centre of Marine Sciences, Universidade do Algarve, Campus de Gambelas, 8005-139, Faro, Portugal
| | - José P da Silva
- CCMAR-Centre of Marine Sciences, Universidade do Algarve, Campus de Gambelas, 8005-139, Faro, Portugal
| | - João Afonso
- CCMAR-Centre of Marine Sciences, Universidade do Algarve, Campus de Gambelas, 8005-139, Faro, Portugal
| | - Adelino V M Canário
- CCMAR-Centre of Marine Sciences, Universidade do Algarve, Campus de Gambelas, 8005-139, Faro, Portugal
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24
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Abstract
Marine animals with complex life cycles may move passively or actively for fertilization, dispersal, predator avoidance, resource acquisition, and migration, and over scales from micrometers to thousands of kilometers. This diversity has catalyzed idiosyncratic and unfocused research, creating unsound paradigms regarding the role of movement in ecology and evolution. The emerging movement ecology paradigm offers a framework to consolidate movement research independent of taxon, life-history stage, scale, or discipline. This review applies the framework to movement among life-history stages in marine animals with complex life cycles to consolidate marine movement research and offer insights for scientists working in aquatic and terrestrial realms. Irrespective of data collection or simulation strategy, breaking each life-history stage down into the fundamental units of movement allows each unit to be studied independently or interactively with other units. Understanding these underlying mechanisms of movement within each life-history stage can then be used to construct lifetime movement paths. These paths can allow further investigation of the relative contributions and interdependencies of steps and phases across a lifetime and how these paths influence larger research topics, such as population-level movements.
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Affiliation(s)
- Richard M Allen
- Department of Ocean Sciences and Department of Biology, Memorial University of Newfoundland, St. John's, Newfoundland A1C 5S7, Canada;
- Department of Oceanography, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Anna Metaxas
- Department of Oceanography, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Paul V R Snelgrove
- Department of Ocean Sciences and Department of Biology, Memorial University of Newfoundland, St. John's, Newfoundland A1C 5S7, Canada;
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25
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Levitan D. DOES BATEMAN'S PRINCIPLE APPLY TO BROADCAST‐SPAWNING ORGANISMS? EGG TRAITS INFLUENCE IN SITU FERTILIZATION RATES AMONG CONGENERIC SEA URCHINS. Evolution 2017; 52:1043-1056. [DOI: 10.1111/j.1558-5646.1998.tb01832.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/1997] [Accepted: 03/24/1998] [Indexed: 11/29/2022]
Affiliation(s)
- Don Levitan
- Department of Biological Science Florida State University Tallahassee Florida 32306‐1100
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26
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Affiliation(s)
- Bruno Pernet
- Department of Zoology and Friday Harbor Laboratories University of Washington 620 University Road Friday Harbor Washington 98250
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27
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Maturana CS, Gérard K, Díaz A, David B, Féral J, Poulin E. Mating system and evidence of multiple paternity in the Antarctic brooding sea urchin Abatus agassizii. Polar Biol 2017; 40:787-797. [DOI: 10.1007/s00300-016-2001-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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28
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Caballes CF, Pratchett MS. Environmental and biological cues for spawning in the crown-of-thorns starfish. PLoS One 2017; 12:e0173964. [PMID: 28355236 DOI: 10.1371/journal.pone.0173964] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2016] [Accepted: 03/01/2017] [Indexed: 11/22/2022] Open
Abstract
Sporadic outbreaks of the coral-eating crown-of-thorns starfish are likely to be due, at least in part, to spatial and temporal variation in reproductive and settlement success. For gonochoric and broadcast spawning species such as crown-of-thorns starfish, spawning synchrony is fundamental for achieving high rates of fertilization. Highly synchronized gamete release within and among distinct populations is typically the result of the entrainment of neurohormonal endogenous rhythms by cues from the environment. In this study, we conducted multiple spawning assays to test the effects of temperature change, reduced salinity and nutrient enrichment of seawater, phytoplankton, gametes (sperm and eggs), and the combined effect of sperm and phytoplankton on the likelihood of spawning in male and female crown-of-thorns starfish. We also investigated sex-specific responses to each of these potential spawning cues. We found that (1) abrupt temperature change (an increase of 4°C) induced spawning in males, but less so in females; (2) males often spawned in response to the presence of phytoplankton, but none of the females spawned in response to these cues; (3) the presence of sperm in the water column induced males and females to spawn, although additive and synergistic effects of sperm and phytoplankton were not significant; and (4) males are more sensitive to the spawning cues tested and most likely spawn prior to females. We propose that environmental cues act as spawning ‘inducers’ by causing the release of hormones (gonad stimulating substance) in sensitive males, while biological cues (pheromones) from released sperm, in turn, act as spawning ‘synchronizers’ by triggering a hormonal cascade resulting in gamete shedding by conspecifics. Given the immediate temporal linkage between the timing of spawning and fertilization events, variability in the extent and synchronicity of gamete release will significantly influence reproductive success and may account for fluctuations in the abundance of crown-of-thorns starfish.
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29
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Tettelbach ST, Europe JR, Tettelbach CRH, Havelin J, Rodgers BS, Furman BT, Velasquez M. Hard clam walking: Active horizontal locomotion of adult Mercenaria mercenaria at the sediment surface and behavioral suppression after extensive sampling. PLoS One 2017; 12:e0173626. [PMID: 28278288 PMCID: PMC5344501 DOI: 10.1371/journal.pone.0173626] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 02/23/2017] [Indexed: 11/18/2022] Open
Abstract
Locomotion of infaunal bivalve mollusks primarily consists of vertical movements related to burrowing; horizontal movements have only been reported for a few species. Here, we characterize hard clam walking: active horizontal locomotion of adults (up to 118 mm shell length, SL) of the commercially important species, Mercenaria mercenaria, at the sediment surface—a behavior only briefly noted in the literature. We opportunistically observed walking over a 10-yr period, at 9 different sites in the Peconic Bays, New York, USA, and tested several hypotheses for the underlying cause of this behavior through quantitative field sampling and reproductive analyses. Hard clam walking was exhibited by males and females at equal frequency, predominantly during June/July and October, when clams were in peak spawning condition. Extensive walking behavior appears to be cued by a minimum population density; we suggest it may be mediated by unidentified pheromone(s), infaunal pressure waves and/or other unidentified factors. There was no directionality exhibited by walking clams, but individuals in an area of extensive walking were highly aggregated and walking clams were significantly more likely to move toward a member of the opposite sex. Thus, we conclude that hard clam walking serves to aggregate mature individuals prior to spawning, thereby facilitating greater fertilization success. In the process of investigating this behavior, however, we apparently oversampled one population and reduced clam densities below the estimated minimum threshold density and, in so doing, suppressed extensive walking for a period of >3 years running. This not only reinforces the importance of detailed field investigations of species biology and ecology, even for those that are considered to be well studied, but also highlights the need for greater awareness of the potential for research activities to affect focal species behavior.
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Affiliation(s)
- Stephen T. Tettelbach
- Department of Biology, LIU-Post, Brookville, New York, United States of America
- * E-mail:
| | - James R. Europe
- Southeast Fisheries Science Center, NOAA, Miami, Florida, United States of America
| | - Christian R. H. Tettelbach
- College of Natural Resources, University of California Berkeley, Berkeley, California, United States of America
| | - Jason Havelin
- Marine Program, Cornell Cooperative Extension of Suffolk County, Southold, New York, United States of America
| | - Brooke S. Rodgers
- School of Marine & Atmospheric Sciences, Stony Brook University, Southampton, New York, United States of America
| | - Bradley T. Furman
- Department of Environmental Sciences, University of Virginia, Charlottesville, Virginia, United States of America
| | - Marissa Velasquez
- Department of Biology, Cornell University, Ithaca, New York, United States of America
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30
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Caballes C, Pratchett M, Raymundo M, Rivera-posada J. Environmental Tipping Points for Sperm Motility, Fertilization, and Embryonic Development in the Crown-of-Thorns Starfish. Diversity 2017; 9:10. [DOI: 10.3390/d9010010] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Rapuano H, Brickner I, Shlesinger T, Meroz-Fine E, Tamir R, Loya Y. Reproductive strategies of the coral Turbinaria reniformis in the northern Gulf of Aqaba (Red Sea). Sci Rep 2017; 7:42670. [PMID: 28195203 PMCID: PMC5307385 DOI: 10.1038/srep42670] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 01/13/2017] [Indexed: 02/07/2023] Open
Abstract
Here we describe for the first time the reproductive biology of the scleractinian coral Turbinaria reniformis studied during three years at the coral reefs of Eilat and Aqaba. We also investigated the possibility of sex change in individually tagged colonies followed over a period of 12 years. T. reniformis was found to be a stable gonochorist (no detected sex change) that reproduces by broadcast spawning 5-6 nights after the full moon of June and July. Spawning was highly synchronized between individuals in the field and in the lab. Reproduction of T. reniformis is temporally isolated from the times at which most other corals reproduce in Eilat. Its relatively long reproductive cycle compared to other hermaphroditic corals may be due to the high reproductive effort associated with the production of eggs by gonochoristic females. Sex ratio in both the Aqaba and Eilat coral populations deviated significantly from a 1:1 ratio. The larger number of males than of females may provide a compensation for sperm limitation due to its dilution in the water column. We posit that such sex allocation would facilitate adaptation within gonochoristic species by increasing fertilization success in low density populations, constituting a phenomenon possibly regulated by chemical communication.
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Affiliation(s)
- Hanna Rapuano
- Department of Zoology, The George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv 69978, Israel
| | - Itzchak Brickner
- Department of Zoology, The George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv 69978, Israel
| | - Tom Shlesinger
- Department of Zoology, The George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv 69978, Israel
| | - Efrat Meroz-Fine
- The Interuniversity Institute for Marine Sciences, P.O. Box 469, Eilat 8810369, Israel
| | - Raz Tamir
- Department of Zoology, The George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv 69978, Israel
- The Interuniversity Institute for Marine Sciences, P.O. Box 469, Eilat 8810369, Israel
| | - Yossi Loya
- Department of Zoology, The George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv 69978, Israel
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Eldon B, Riquet F, Yearsley J, Jollivet D, Broquet T. Current hypotheses to explain genetic chaos under the sea. Curr Zool 2016; 62:551-566. [PMID: 29491945 PMCID: PMC5829445 DOI: 10.1093/cz/zow094] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [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: 04/03/2016] [Accepted: 08/27/2016] [Indexed: 01/07/2023] Open
Abstract
Chaotic genetic patchiness (CGP) refers to surprising patterns of spatial and temporal genetic structure observed in some marine species at a scale where genetic variation should be efficiently homogenized by gene flow via larval dispersal. Here we review and discuss 4 mechanisms that could generate such unexpected patterns: selection, sweepstakes reproductive success, collective dispersal, and temporal shifts in local population dynamics. First, we review examples where genetic differentiation at specific loci was driven by diversifying selection, which was historically the first process invoked to explain CGP. Second, we turn to neutral demographic processes that may drive genome-wide effects, and whose effects on CGP may be enhanced when they act together. We discuss how sweepstakes reproductive success accelerates genetic drift and can thus generate genetic structure, provided that gene flow is not too strong. Collective dispersal is another mechanism whereby genetic structure can be maintained regardless of dispersal intensity, because it may prevent larval cohorts from becoming entirely mixed. Theoretical analyses of both the sweepstakes and the collective dispersal ideas are presented. Finally, we discuss an idea that has received less attention than the other ones just mentioned, namely temporal shifts in local population dynamics.
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Affiliation(s)
- Bjarki Eldon
- Museum für Naturkunde Berlin, Leibniz Institut für Evolutions- und
Biodiversitätsforschung, Berlin 10115, Germany
| | - Florentine Riquet
- Université Montpellier 2, Place Eugène Bataillon, 34095 Montpellier Cedex 5,
France
- ISEM - CNRS, UMR 5554, SMEL, 2 rue des Chantiers, Sète 34200, France
| | - Jon Yearsley
- School of Biology and Environmental Science and UCD Earth Institute,
University College Dublin, Belfield, Dublin 4, Ireland
| | - Didier Jollivet
- Centre National de la Recherche Scientifique, Team Adaptation and Biology of
Invertebrates in Extreme Environments, Station Biologique de Roscoff, Roscoff 29680,
France
- Sorbonne Universités, Université Pierre et Marie Curie, Unité Mixte de
Recherche 7144, Station Biologique de Roscoff, Roscoff 29680, France
| | - Thomas Broquet
- Sorbonne Universités, Université Pierre et Marie Curie, Unité Mixte de
Recherche 7144, Station Biologique de Roscoff, Roscoff 29680, France
- Centre National de la Recherche Scientifique, Team Diversity and
Connectivity of Coastal Marine Landscapes, Station Biologique de Roscoff, Roscoff 29680,
France
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Cote J, Bocedi G, Debeffe L, Chudzińska ME, Weigang HC, Dytham C, Gonzalez G, Matthysen E, Travis J, Baguette M, Hewison AJM. Behavioural synchronization of large-scale animal movements - disperse alone, but migrate together? Biol Rev Camb Philos Soc 2016; 92:1275-1296. [DOI: 10.1111/brv.12279] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 03/23/2016] [Accepted: 04/06/2016] [Indexed: 01/10/2023]
Affiliation(s)
- Julien Cote
- ENFA and UMR 5174 EDB (Laboratoire Évolution & Diversité Biologique), CNRS; Université Toulouse III - Paul Sabatier; Toulouse cedex 9 F-31062 France
| | - Greta Bocedi
- Institute of Biological and Environmental Sciences; University of Aberdeen; Aberdeen AB24 2TZ UK
| | - Lucie Debeffe
- CEFS, INRA; Université de Toulouse; Castanet Tolosan 31320 France
- Department of Biology; University of Saskatchewan; Saskatoon SK S7N 5E2 Canada
| | | | - Helene C. Weigang
- Department of Mathematics and Statistics; University of Helsinki; P.O. Box 68 Helsinki 00014 Finland
| | - Calvin Dytham
- Department of Biology; University of York; York YO10 5DD UK
| | - Georges Gonzalez
- CEFS, INRA; Université de Toulouse; Castanet Tolosan 31320 France
| | - Erik Matthysen
- Department of Biology; University of Antwerp; Antwerp B-2610 Belgium
| | - Justin Travis
- Institute of Biological and Environmental Sciences; University of Aberdeen; Aberdeen AB24 2TZ UK
| | - Michel Baguette
- Station d'Ecologie Théorique et Experimentale; CNRS UMR 5321; Moulis 09200 France
- Institut De Systématique, Evolution et Biodiversité, UMR 7205; Muséum National d'Histoire Naturelle; Paris cedex 5 FR-75005 France
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Rojas-Montiel B, Benítez-Villalobos F. Ecología poblacional de Diadema mexicanum (Echinodermata: Echinoidea) en dos comunidades arrecifales de bahías de Huatulco, Oaxaca, México. REV MEX BIODIVERS 2015. [DOI: 10.7550/rmb.42918] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Lasley-Rasher RS, Kramer AM, Burdett-Coutts V, Yen J. Assessing the in situ fertilization status of two marine copepod species, Temora longicornis and Eurytemora herdmani; how common are unfertilized eggs in nature? PLoS One 2014; 9:e112920. [PMID: 25397669 PMCID: PMC4232583 DOI: 10.1371/journal.pone.0112920] [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] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 10/16/2014] [Indexed: 11/18/2022] Open
Abstract
We utilized an egg staining technique to measure the in situ fertilization success of two marine copepod species, Temora longicornis and Eurytemora herdmani from May to October 2008 in coastal Maine and correlated fertilization success with environmental conditions in their habitat. T. longicornis is a free spawning species that releases eggs into the ambient seawater after mating. In contrast, E. herdmani carries eggs in an egg sac until they hatch. The proportion of fertilized eggs within E. herdmani egg sacs was significantly higher than the freely spawned clutches of T. longicornis. This may be a result of the asymmetrical costs associated with carrying vs. spawning unfertilized eggs. T. longicornis frequently laid both fertilized and unfertilized eggs within their clutch. T. longicornis fertilization was negatively associated with chlorophyll concentration and positively associated with population density in their local habitat. The fertilization status of E. herdmani egg sacs was high throughout the season, but the proportion of ovigerous females was negatively associated with an interaction between predators and the proportion of females in the population. This study emphasizes that, in addition to population level processes, community and ecosystem level processes strongly influence the fertilization success and subsequent productivity of copepods.
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Affiliation(s)
- Rachel S. Lasley-Rasher
- School of Biology, Georgia Institute of Technology, Atlanta, Georgia, United States of America
- * E-mail:
| | - Andrew M. Kramer
- Odum School of Ecology, University of Georgia, Athens, Georgia, United States of America
| | - Victoria Burdett-Coutts
- Department of Ocean Science, Memorial University of Newfoundland, St. John’s, Newfoundland and Labrador, Canada
| | - Jeannette Yen
- School of Biology, Georgia Institute of Technology, Atlanta, Georgia, United States of America
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Morita M, Awata S, Yorifuji M, Ota K, Kohda M, Ochi H. Bower-building behaviour is associated with increased sperm longevity in Tanganyikan cichlids. J Evol Biol 2014; 27:2629-43. [PMID: 25330280 DOI: 10.1111/jeb.12522] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 09/17/2014] [Accepted: 09/23/2014] [Indexed: 11/28/2022]
Abstract
We investigated the evolutionary relationship between spawning behaviour and sperm motility traits among Tanganyikan mouth-brooding cichlid species that have developed diverse mating behaviours and male sexual traits. Mouth-brooding behaviour is common among these fish, but different species demonstrate a range of spawning behaviours, bower construction, male sexual traits and timing of gamete release. We observed spawning behaviours and compared sperm motility traits of 28 Tanganyikan mouth-brooding cichlids to elucidate the evolutionary correlations between these traits. Sperm longevity was considerably longer in bower-building species that construct crater-shaped spawning sites compared with species that do not build bowers. Male bower builders released sperm in the pit of the bower prior to spawning, and the time from ejaculation to fertilization was longer. Conversely, most mouth-brooding cichlids deposited semen directly into the female buccal cavity, and spawned eggs were immediately picked up to be placed inside the cavity; thus, the time from ejaculation to fertilization was short. These observations suggest that increased sperm longevity is favoured in bower builders. Comparative phylogenetic analyses suggested that bower-building behaviour and greater time from ejaculation to fertilization are associated with the extension of sperm longevity, whereas sperm competition rank does not play a major role. In addition, bower-building behaviour preceded the emergence of increased sperm longevity. These results indicate that the extension of sperm longevity as a result of the emergence of bower builders may have acted as an evolutionary attractor for sperm longevity.
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Affiliation(s)
- M Morita
- Sesoko Station, Tropical Biosphere Research Center, University of the Ryukyus, Motobu, Japan
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37
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Abstract
Proteins expressed on the surface of sperm and egg mediate gametic compatibility and these proteins can be subject to intense positive selection. In this review, we discuss what is known about the patterns of adaptive evolution of gamete recognition proteins (GRPs). We focus on species that broadcast eggs and sperm into the environment for external fertilization, as the ease of observing and manipulating gamete interactions has allowed for greater advances in the understanding of GRP evolution, uncomplicated by confounding behavioral and physiological components that offer alternative evolutionary targets in internal fertilizers. We discuss whether interspecific mechanisms, such as selection to avoid fertilization between species (reinforcement selection), or intraspecific mechanisms, such as selection to increase (or decrease) the affinity between eggs and sperm based on the intensity of sperm competition, may be responsible for the pattern of GRP evolution observed. Variation in these proteins appears to influence gametic compatibility; GRP divergence among species is a better predictor of hybrid fertilization than neutral genetic markers and GRP variation within species predicts reproductive success among individuals within a population. Evidence suggests that sperm competition may play a large role in the evolution of gametic compatibility.
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Affiliation(s)
- E T Kosman
- Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA
| | - D R Levitan
- Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA
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38
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Klibansky LKJ, McCartney MA. Conspecific sperm precedence is a reproductive barrier between free-spawning marine mussels in the northwest atlantic mytilus hybrid zone. PLoS One 2014; 9:e108433. [PMID: 25268856 PMCID: PMC4182449 DOI: 10.1371/journal.pone.0108433] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2014] [Accepted: 08/29/2014] [Indexed: 11/18/2022] Open
Abstract
Reproductive isolation at the gamete stage has become a focus of speciation research because of its potential to evolve rapidly between closely related species. Conspecific sperm precedence (CSP), a type of gametic isolation, has been demonstrated in a number of taxa, both marine and terrestrial, with the potential to play an important role in speciation. Free-spawning marine invertebrates are ideal subjects for the study of CSP because of a likely central role for gametic barriers in reproductive isolation. The western Atlantic Mytilus blue mussel hybrid zone, ranging from the Atlantic Canada to eastern Maine, exhibits characteristics conducive to the study of CSP. Previous studies have shown that gametic incompatibility is incomplete, variable in strength and the genotype distribution is bimodal-dominated by the parental species, with a low frequency of hybrids. We conducted gamete crossing experiments using M. trossulus and M. edulis individuals collected from natural populations during the spring spawning season in order to detect the presence or absence of CSP within this hybrid zone. We detected CSP, defined here as a reduction in heterospecific offspring from competitive fertilizations in vitro compared to that seen in non-competitive fertilizations, in five of the twelve crosses in which conspecific crosses were detectable. This is the first finding of CSP in a naturally hybridizing population of a free-spawning marine invertebrate. Our findings support earlier predictions that CSP can promote assortative fertilization in bimodal hybrid zones, further advancing their hypothesized progression towards full speciation. Despite strong CSP numerous heterospecific fertilizations remain, reinforcing the hypothesis that compatible females are a source of hybrid offspring in mixed natural spawns.
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Affiliation(s)
- Lara K. J. Klibansky
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, North Carolina, United States of America
- * E-mail:
| | - Michael A. McCartney
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, North Carolina, United States of America
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Abstract
Ocean acidification impacts fertilization in some species of sea urchin, but whether sensitivity is great enough to be influenced by present-day pH variability has not been documented. In this study, fertilization in two congeneric sea urchins, Strongylocentrotus purpuratus and S. franciscanus, was found to be sensitive to reduced pH, <7.50, but only within a range of sperm-egg ratios that was species-specific. By further testing fertilization across a broad range of pH, pH-fertilization curves were generated and revealed that S. purpuratus was largely robust to pH, while fertilization in S. franciscanus was sensitive to even modest reductions in pH. Combining the pH-fertilization response curves with pH data collected from these species' habitat demonstrated that relative fertilization success remained high for S. purpuratus but could be as low as 79% for S. franciscanus during periods of naturally low pH. In order for S. franciscanus to maintain high fertilization success in the present and future, adequate adult densities, and thus sufficient sperm-egg ratios, will be required to negate the effects of low pH. In contrast, fertilization of S. purpuratus was robust to a broad range of pH, encompassing both present-day and future ocean acidification scenarios, even though the two congeners have similar habitats.
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40
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Roth G, Schreiber SJ. Pushed beyond the brink: Allee effects, environmental stochasticity, and extinction. J Biol Dyn 2014; 8:187-205. [PMID: 25275425 PMCID: PMC4241649 DOI: 10.1080/17513758.2014.962631] [Citation(s) in RCA: 10] [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] [Figures] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 08/18/2014] [Indexed: 06/03/2023]
Abstract
To understand the interplay between environmental stochasticity and Allee effects, we analyse persistence, asymptotic extinction, and conditional persistence for stochastic difference equations. Our analysis reveals that persistence requires that the geometric mean of fitness at low densities is greater than one. When this geometric mean is less than one, asymptotic extinction occurs with high probability for low initial population densities. Additionally, if the population only experiences positive density-dependent feedbacks, conditional persistence occurs provided the geometric mean of fitness at high population densities is greater than one. However, if the population experiences both positive and negative density-dependent feedbacks, conditional persistence only occurs if environmental fluctuations are sufficiently small. We illustrate counter-intuitively that environmental fluctuations can increase the probability of persistence when populations are initially at low densities, and can cause asymptotic extinction of populations experiencing intermediate predation rates despite conditional persistence occurring at higher predation rates.
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Affiliation(s)
- Gregory Roth
- Department of Evolution and Ecology, One Shields Avenue, University of California, Davis, CA95616USA
| | - Sebastian J. Schreiber
- Department of Evolution and Ecology, One Shields Avenue, University of California, Davis, CA95616USA
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Hold N, Murray LG, Hinz H, Neill SP, Lass S, Lo M, Kaiser MJ. Environmental drivers of small scale spatial variation in the reproductive schedule of a commercially important bivalve mollusc. Mar Environ Res 2013; 92:144-153. [PMID: 24138797 DOI: 10.1016/j.marenvres.2013.09.011] [Citation(s) in RCA: 3] [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: 05/23/2013] [Revised: 09/05/2013] [Accepted: 09/12/2013] [Indexed: 06/02/2023]
Abstract
Understanding variability in reproductive schedules is essential to the management of recruitment limited fisheries such as that of Pecten maximus. Small scale (<5 km) variation in gonad condition and the onset of spawning of P. maximus were found among commercial scallop grounds in Isle of Man waters. Environmental and fishing drivers of these spatial patterns were investigated using a generalised additive model. Rate of change in temperature over the month prior to sampling was identified as the short term driver of gonad weight associated with the autumn spawning event. Long term drivers were average annual chlorophyll a concentration, scallop density, stratification index and shell size. The model explained 42.8% of deviance in gonad weight. Within site variation in gonad condition was high, indicating a "bet hedging" reproductive strategy which may decrease the chance of fertilisation especially at low densities. Therefore, areas protected from fishing, where scallop densities can increase may help buffer against reproductive failure. An increase in shell length from 100 mm to 110 mm equated to an increase of approximately 20% in gonad weight. Protecting scallops from fishing mortality until 110 mm (age four) compared to 100 mm (age three) may lead to an overall increase in lifetime reproductive output by a factor of 3.4.
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Affiliation(s)
- Natalie Hold
- School of Ocean Sciences, Bangor University, Menai Bridge, Isle of Anglesey LL59 5AB, UK.
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Vihtakari M, Hendriks I, Holding J, Renaud P, Duarte C, Havenhand J. Effects of Ocean Acidification and Warming on Sperm Activity and Early Life Stages of the Mediterranean Mussel (Mytilus galloprovincialis). Water 2013; 5:1890-915. [DOI: 10.3390/w5041890] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Kregting LT, Bass AL, Guadayol Ò, Yund PO, Thomas FI. Effects of oscillatory flow on fertilization in the green sea urchin Strongylocentrotus droebachiensis. PLoS One 2013; 8:e76082. [PMID: 24098766 DOI: 10.1371/journal.pone.0076082] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 08/23/2013] [Indexed: 12/29/2022] Open
Abstract
Broadcast spawning invertebrates that live in shallow, high-energy coastal habitats are subjected to oscillatory water motion that creates unsteady flow fields above the surface of animals. The frequency of the oscillatory fluctuations is driven by the wave period, which will influence the stability of local flow structures and may affect fertilization processes. Using an oscillatory water tunnel, we quantified the percentage of eggs fertilized on or near spawning green sea urchins, Strongylocentrotus droebachiensis. Eggs were sampled in the water column, wake eddy, substratum and aboral surface under a range of different periods (T = 4.5 – 12.7 s) and velocities of oscillatory flow. The root-mean-square wave velocity (rms(uw)) was a good predictor of fertilization in oscillatory flow, although the root-mean-square of total velocity (rms(u)), which incorporates all the components of flow (current, wave and turbulence), also provided significant predictions. The percentage of eggs fertilized varied between 50 – 85% at low flows (rms(uw) <0.02 m s−1), depending on the location sampled, but declined to below 10% for most locations at higher rms(uw). The water column was an important location for fertilization with a relative contribution greater than that of the aboral surface, especially at medium and high rms(uw) categories. We conclude that gametes can be successfully fertilized on or near the parent under a range of oscillatory flow conditions.
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Abstract
When populations reach small size, an extinction risk vortex may arise from genetic (inbreeding depression, genetic drift) and ecological (demographic stochasticity, Allee effects, environmental fluctuation) processes. The relative contribution of these processes to extinction in wild populations is unknown, but important for conserving endangered species. In experimental field populations of a harvested kelp (Postelsia palmaeformis), in which we independently varied initial genetic diversity (completely inbred, control, outbred) and population size, ecological processes dominated the risk of extinction, whereas the contribution of genetic diversity was slight. Our results match theoretical predictions that demographic processes will generally doom small populations to extinction before genetic effects act strongly, prioritize detailed ecological analysis over descriptions of genetic structure in assessing conservation of at-risk species, and highlight the need for field experiments manipulating both demographics and genetic structure on long-term extinction risk.
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Affiliation(s)
- J Timothy Wootton
- Department of Ecology and Evolution, University of Chicago, 1101 East 57th Street, Chicago, IL 60637, USA.
| | - Catherine A Pfister
- Department of Ecology and Evolution, University of Chicago, 1101 East 57th Street, Chicago, IL 60637, USA
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45
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Claisse JT, Williams JP, Ford T, Pondella DJ, Meux B, Protopapadakis L. Kelp forest habitat restoration has the potential to increase sea urchin gonad biomass. Ecosphere 2013. [DOI: 10.1890/es12-00408.1] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Serrano E, Coma R, Ribes M, Weitzmann B, García M, Ballesteros E. Rapid northward spread of a zooxanthellate coral enhanced by artificial structures and sea warming in the western Mediterranean. PLoS One 2013; 8:e52739. [PMID: 23341904 PMCID: PMC3544859 DOI: 10.1371/journal.pone.0052739] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 11/21/2012] [Indexed: 11/30/2022] Open
Abstract
The hermatypic coral Oculina patagonica can drive a compositional shift in shallow water benthic marine communities in the northwestern Mediterranean. Here, we analyze a long-term, large-scale observational dataset to characterize the dynamics of the species' recent northward range shift along the coast of Catalonia and examine the main factors that could have influenced this spread. The variation in the distributional range of Oculina patagonica was examined by monitoring 223 locations including natural and artificial habitats along >400 km of coastline over the last 19 years (1992–2010). Abundance of the species increased from being present in one location in 1992 to occur on 19% of the locations in 2010, and exhibited an acceleration of its spreading over time driven by the join action of neighborhood and long-distance dispersal. However, the pattern of spread diverged between artificial and natural habitats. A short lag phase and a high slope on the exponential phase characterized the temporal pattern of spread on artificial habitats in contrast to that observed on natural ones. Northward expansion has occurred at the fastest rate (22 km year−1) reported for a coral species thus far, which is sufficiently fast to cope with certain climate warming predictions. The pattern of spread suggests that this process is mediated by the interplay of (i) the availability of open space provided by artificial habitats, (ii) the seawater temperature increase with the subsequent extension of the growth period, and (iii) the particular biological features of O. patagonica (current high growth rates, early reproduction, and survival to low temperature and in polluted areas). These results are indicative of an ongoing fundamental modification of temperate shallow water assemblages, which is consistent with the predictions indicating that the Mediterranean Sea is one of the most sensitive regions to global change.
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Affiliation(s)
- Eduard Serrano
- Centre d'Estudis Avançats de Blanes-Consejo Superior de Investigaciones Científicas (CEAB-CSIC), Blanes, Girona, Spain
- Institut de Ciències del Mar-Consejo Superior de Investigaciones Científicas (ICM-CSIC), Barcelona, Spain
- * E-mail:
| | - Rafel Coma
- Centre d'Estudis Avançats de Blanes-Consejo Superior de Investigaciones Científicas (CEAB-CSIC), Blanes, Girona, Spain
| | - Marta Ribes
- Institut de Ciències del Mar-Consejo Superior de Investigaciones Científicas (ICM-CSIC), Barcelona, Spain
| | - Boris Weitzmann
- Centre d'Estudis Avançats de Blanes-Consejo Superior de Investigaciones Científicas (CEAB-CSIC), Blanes, Girona, Spain
| | - María García
- Centre d'Estudis Avançats de Blanes-Consejo Superior de Investigaciones Científicas (CEAB-CSIC), Blanes, Girona, Spain
| | - Enric Ballesteros
- Centre d'Estudis Avançats de Blanes-Consejo Superior de Investigaciones Científicas (CEAB-CSIC), Blanes, Girona, Spain
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Schlegel P, Havenhand JN, Gillings MR, Williamson JE. Individual variability in reproductive success determines winners and losers under ocean acidification: a case study with sea urchins. PLoS One 2012; 7:e53118. [PMID: 23300876 PMCID: PMC3531373 DOI: 10.1371/journal.pone.0053118] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Accepted: 11/28/2012] [Indexed: 11/18/2022] Open
Abstract
Background Climate change will lead to intense selection on many organisms, particularly during susceptible early life stages. To date, most studies on the likely biotic effects of climate change have focused on the mean responses of pooled groups of animals. Consequently, the extent to which inter-individual variation mediates different selection responses has not been tested. Investigating this variation is important, since some individuals may be preadapted to future climate scenarios. Methodology/Principal Findings We examined the effect of CO2-induced pH changes (“ocean acidification”) in sperm swimming behaviour on the fertilization success of the Australasian sea urchin Heliocidaris erythrogramma, focusing on the responses of separate individuals and pairs. Acidification significantly decreased the proportion of motile sperm but had no effect on sperm swimming speed. Subsequent fertilization experiments showed strong inter-individual variation in responses to ocean acidification, ranging from a 44% decrease to a 14% increase in fertilization success. This was partly explained by the significant relationship between decreases in percent sperm motility and fertilization success at ΔpH = 0.3, but not at ΔpH = 0.5. Conclusions and Significance The effects of ocean acidification on reproductive success varied markedly between individuals. Our results suggest that some individuals will exhibit enhanced fertilization success in acidified oceans, supporting the concept of ‘winners’ and ‘losers’ of climate change at an individual level. If these differences are heritable it is likely that ocean acidification will lead to selection against susceptible phenotypes as well as to rapid fixation of alleles that allow reproduction under more acidic conditions. This selection may ameliorate the biotic effects of climate change if taxa have sufficient extant genetic variation upon which selection can act.
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Affiliation(s)
- Peter Schlegel
- Department of Biological Sciences, Macquarie University, Sydney, Australia.
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Johnson DW, Monro K, Marshall DJ. THE MAINTENANCE OF SPERM VARIABILITY: CONTEXT-DEPENDENT SELECTION ON SPERM MORPHOLOGY IN A BROADCAST SPAWNING INVERTEBRATE. Evolution 2012; 67:1383-95. [DOI: 10.1111/evo.12022] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Accepted: 11/01/2012] [Indexed: 01/15/2023]
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Muth AF. Effects of Zoospore Aggregation and Substrate Rugosity on Kelp Recruitment Success. J Phycol 2012; 48:1374-1379. [PMID: 27009989 DOI: 10.1111/j.1529-8817.2012.01211.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Accepted: 04/29/2012] [Indexed: 06/05/2023]
Abstract
Successful kelp recruitment is important for kelp population persistence and associated kelp forest communities. The proximity of settled kelp zoospores is a known requirement for successful kelp recruitment and proximity can be increased as zoospores aggregate. Substrate rugosity can also be an important factor affecting macroalgal settlement and recruitment in wave-swept areas, and may affect kelp recruitment by aggregating zoospores. In this study, kelp zoospores were cultured at different levels of small-scale aggregation and kelp recruitment was quantified. Sporophyte production significantly increased as zoospores became more aggregated indicating that processes that aggregate kelp zoospores have the potential to enhance kelp recruitment. A 13-month field experiment demonstrated differential kelp recruitment onto settlement plates that mimicked surface rugosities of two common rock types within Stillwater Cove, Carmel Bay in central California (Carmelo Formation sandstone and Santa Lucia granodiorite). Significantly more kelp recruited to molds mimicking granodiorite over the yearlong study (granodiorite = 2.7 recruits ± SE 0.50, sandstone = 1.2 recruits ± SE 0.51). There was a significant difference in recruitment between seasons and this variability was due to the fact that spring had the highest average number of kelp recruits per mold. However, the interaction between substrate and season was not significant. This study emphasizes the importance of kelp zoospore aggregation on kelp recruitment and demonstrates that small-scale rugosity affects kelp recruitment.
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Affiliation(s)
- Arley F Muth
- Moss Landing Marine Laboratories, Moss Landing, California, 95039, USA
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Abstract
Summary
Broadcast-spawning benthic invertebrates synchronously release sperm and eggs from separate locations into the surrounding flow, whereupon the process depends on structured stirring by the flow field (at large scales), and sperm motility and taxis (at small scales) to bring the gametes together. The details of the relevant physical and biological aspects of the problem that result in successful and efficient fertilization are not well understood. This review paper includes relevant work from both the physical and biological communities to synthesize a more complete understanding of the processes that govern fertilization success; the focus is on the role of structured stirring on the dispersal and aggregation of gametes. The review also includes a summary of current trends and approaches for numerical and experimental simulations of broadcast spawning.
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