scholarly journals Effects of Predator-Prey Interactions on Predator Traits: Differentiation of Diets and Venoms of a Marine Snail

Toxins ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 299 ◽  
Author(s):  
David A. Weese ◽  
Thomas F. Duda
Keyword(s):  
Resource Utilization ◽  
Species Interactions ◽  
Expression Patterns ◽  
Easter Island ◽  
Island Population ◽  
Predator Prey ◽  
Dietary Breadth ◽  
Venom Composition ◽  
Marine Snails ◽  
Prey Utilization

Species interactions are fundamental ecological forces that can have significant impacts on the evolutionary trajectories of species. Nonetheless, the contribution of predator-prey interactions to genetic and phenotypic divergence remains largely unknown. Predatory marine snails of the family Conidae exhibit specializations for different prey items and intraspecific variation in prey utilization patterns at geographic scales. Because cone snails utilize venom to capture prey and venom peptides are direct gene products, it is feasible to examine the evolution of genes associated with changes in resource utilization. Here, we compared feeding ecologies and venom duct transcriptomes of individuals from three populations of Conus miliaris, a species that exhibits geographic variation in prey utilization and dietary breadth, in order to determine the extent to which dietary differences are correlated with differences in venom composition, and if expanded niche breadth is associated with increased variation in venom composition. While populations showed little to no overlap in resource utilization, taxonomic richness of prey was greatest at Easter Island. Changes in dietary breadth were associated with differences in expression patterns and increased genetic differentiation of toxin-related genes. The Easter Island population also exhibited greater diversity of toxin-related transcripts, but did not show increased variance in expression of these transcripts. These results imply that differences in dietary breadth contribute more to the structural and regulatory differentiation of venoms than differences in diet.

scholarly journals Diet Diversity in Carnivorous Terebrid Snails Is Tied to the Presence and Absence of a Venom Gland

Toxins ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 108
Author(s):  
Juliette Gorson ◽  
Giulia Fassio ◽  
Emily S. Lau ◽  
Mandë Holford
Keyword(s):  
Venom Gland ◽  
Molecular Study ◽  
Strongly Correlated ◽  
Animal Evolution ◽  
Diet Diversity ◽  
Dietary Breadth ◽  
Venom Composition ◽  
Marine Snails ◽  
Predatory Strategy ◽  
Definition Of

Predator-prey interactions are thought to play a driving role in animal evolution, especially for groups that have developed venom as their predatory strategy. However, how the diet of venomous animals influences the composition of venom arsenals remains uncertain. Two prevailing hypotheses to explain the relationship between diet and venom composition focus on prey preference and the types of compounds in venom, and a positive correlation between dietary breadth and the number of compounds in venom. Here, we examined venom complexity, phylogenetic relationship, collection depth, and biogeography of the Terebridae (auger snails) to determine if repeated innovations in terebrid foregut anatomy and venom composition correspond to diet variation. We performed the first molecular study of the diet of terebrid marine snails by metabarcoding the gut content of 71 terebrid specimens from 17 species. Our results suggest that the presence or absence of a venom gland is strongly correlated with dietary breadth. Specifically, terebrid species without a venom gland displayed greater diversity in their diet. Additionally, we propose a revision of the definition of venom complexity in conoidean snails to more accurately capture the breadth of ecological influences. These findings suggest that prey diet is an important factor in terebrid venom evolution and diversification and further investigations of other understudied organisms, like terebrids, are needed to develop robust hypotheses in this area.

scholarly journals Dietary Breadth is Positively Correlated with Venom Complexity in Cone Snails

2015 ◽  
Author(s):  
Mark A Phuong ◽  
Gusti N Mahardika ◽  
Michael E Alfaro
Keyword(s):  
Evolutionary Dynamics ◽  
Gene Diversity ◽  
Expression Patterns ◽  
Snail Species ◽  
Ecological Data ◽  
Dietary Breadth ◽  
Venom Composition ◽  
Taxonomic Class ◽  
Venom Evolution ◽  
Cone Snails

Although diet is believed to be a major factor underlying the evolution of venom, few comparative studies examine both venom composition and diet across a radiation of venomous species. Cone snails within the family, Conidae, comprise more than 700 species of carnivorous marine snails that capture their prey by using a cocktail of venomous neurotoxins (conotoxins or conopeptides). Venom composition across species has been previously hypothesized to be shaped by (a) prey taxonomic class (i.e., worms, molluscs, or fish) and (b) dietary breadth. We tested these hypotheses under a comparative phylogenetic framework using ecological data in conjunction with venom duct transcriptomes sequenced from 12 phylogenetically disparate cone snail species, including 10 vermivores (worm-eating), one molluscivore, and one generalist. We discovered 2223 unique conotoxin precursor peptides that encoded 1864 unique mature toxins across all species, >90% of which are new to this study. In addition, we identified two novel gene superfamilies and 16 novel cysteine frameworks. Each species exhibited unique venom profiles, with venom composition and expression patterns among species dominated by a restricted set of gene superfamilies and mature toxins. In contrast with the dominant paradigm for interpreting Conidae venom evolution, prey taxonomic class did not predict venom composition patterns among species. Our results suggests that cone snails have either evolved species-specific expression patterns likely as a consequence of the rapid evolution of conotoxin genes, or that traditional means of categorizing prey type (i.e., worms, mollusc, or fish) and conotoxins (i.e., by gene superfamily) do not accurately encapsulate evolutionary dynamics between diet and venom composition. We also found a significant positive relationship between dietary breadth and measures of conotoxin complexity. These results indicate that species with more generalized diets tend to have more complex venoms and utilize a greater number of venom genes for prey capture. Whether this increased gene diversity confers an increased capacity for evolutionary change remains to be tested. Overall, our results corroborate the key role of diet in influencing patterns of venom evolution in cone snails and other venomous radiations.

scholarly journals Effects of geographical heterogeneity in species interactions on the evolution of venom genes

2015 ◽  
Vol 282 (1805) ◽  
pp. 20141984 ◽  
Author(s):  
Dan Chang ◽  
Amy M. Olenzek ◽  
Thomas F. Duda
Keyword(s):  
Species Interactions ◽  
Prey Capture ◽  
Biotic Interactions ◽  
American Samoa ◽  
Allelic Frequency ◽  
Geographical Differences ◽  
Dietary Breadth ◽  
Geographical Heterogeneity ◽  
Genes Encoding ◽  
Prey Utilization

Geographical heterogeneity in the composition of biotic interactions can create a mosaic of selection regimes that may drive the differentiation of phenotypes that operate at the interface of these interactions. Nonetheless, little is known about effects of these geographical mosaics on the evolution of genes encoding traits associated with species interactions. Predatory marine snails of the family Conidae use venom, a cocktail of conotoxins, to capture prey. We characterized patterns of geographical variation at five conotoxin genes of a vermivorous species, Conus ebraeus , at Hawaii, Guam and American Samoa, and evaluated how these patterns of variation are associated with geographical heterogeneity in prey utilization. All populations show distinct patterns of prey utilization. Three ‘highly polymorphic’ conotoxin genes showed significant geographical differences in allelic frequency, and appear to be affected by different modes of selection among populations. Two genes exhibited low levels of diversity and a general lack of differentiation among populations. Levels of diversity of ‘highly polymorphic’ genes exhibit a positive relationship with dietary breadth. The different patterns of evolution exhibited by conotoxin genes suggest that these genes play different roles in prey capture, and that some genes are more greatly affected by differences in predator–prey interactions than others. Moreover, differences in dietary breadth appear to have a greater influence on the differentiation of venoms than differences in the species of prey.

scholarly journals Impacts of predator-mediated interactions along a climatic gradient on the population dynamics of an alpine bird

2020 ◽  
Author(s):  
Diana E. Bowler ◽  
Mikkel A. J. Kvasnes ◽  
Hans C. Pedersen ◽  
Brett K. Sandercock ◽  
Erlend B. Nilsen
Keyword(s):  
Population Dynamics ◽  
Species Interactions ◽  
Climatic Conditions ◽  
Boreal Ecosystems ◽  
Prey Switching ◽  
Predator Prey ◽  
Classic Theory ◽  
Species Population ◽  
Cyclic Dynamics ◽  
Ground Nesting

AbstractAccording to classic theory, species’ population dynamics and distributions are less influenced by species interactions under harsh climatic conditions compared to under more benign climatic conditions. In alpine and boreal ecosystems in Fennoscandia, the cyclic dynamics of rodents strongly affect many other species, including ground-nesting birds such as ptarmigan. According to the ‘alternative prey hypothesis’ (APH), the densities of ground-nesting birds and rodents are positively associated due to predator-prey dynamics and prey-switching. However, it remains unclear how the strength of these predator-mediated interactions change along a climatic harshness gradient in comparison with the effects of climatic variation. We built a hierarchical Bayesian model to estimate the sensitivity of ptarmigan populations to interannual variation in climate and rodent occurrence across Norway during 2007–2017. Ptarmigan abundance was positively linked with rodent occurrence, consistent with the APH. Moreover, we found that rodent dynamics had stronger effects on ptarmigan in colder regions. Our study highlights how species interactions play an important role for the population dynamics of species at higher latitudes and suggests that they can become even more important in the most climatically harsh regions.

scholarly journals Multispecies integrated population model reveals bottom-up dynamics in a seabird predator-prey system

2020 ◽  
Author(s):  
Maud Quéroué ◽  
Christophe Barbraud ◽  
Frédéric Barraquand ◽  
Daniel Turek ◽  
Karine Delord ◽  
...  
Keyword(s):  
Breeding Success ◽  
Species Interactions ◽  
Interspecific Interactions ◽  
Demographic Parameters ◽  
Multiple Sources ◽  
Bottom Up ◽  
Climate Conditions ◽  
Predator Prey ◽  
Relative Contribution ◽  
Prey System

AbstractAssessing the effects of climate and interspecific relationships on communities is challenging because of the complex interplay between species population dynamics, their interactions, and the need to integrate information across several biological levels (individuals – populations – communities). Usually used to quantify species interactions, integrated population models (IPMs) have recently been extended to communities. These models allow fitting multispecies matrix models to data from multiple sources while simultaneously accounting for various sources of uncertainty in each data source. We used multispecies IPMs accommodating climate conditions to quantify the relative contribution of climate vs. interspecific interactions on demographic parameters, such as survival and breeding success, in the dynamics of a predator-prey system. We considered a stage-structured predator–prey system combining 22 years of capture–recapture data and population counts of two seabirds, the Brown Skua (Catharacta lönnbergi) and its main prey the Blue Petrel (Halobaena caerulea) both breeding on the Kerguelen Islands in the Southern Ocean. Our results showed that climate and predator-prey interactions drive the demography of skuas and petrels in different ways. The breeding success of skuas appeared to be largely driven by the number of petrels and to a lesser extent by intraspecific density-dependence. In contrast, there was no evidence of predation effects on the demographic parameters of petrels, which were affected by oceanographic factors (chlorophyll a and sea surface temperature anomalies). We conclude that bottom-up mechanisms are the main drivers of this skua-petrel system. We discuss the mechanisms by which climate variability and predator-prey relationships may affect the demographic parameters of these seabirds. Taking into account both species interactions and environmental covariates in the same analysis improved our understanding of species dynamics.

Predator–prey interactions and climate change

2019 ◽  
pp. 199-220 ◽  
Author(s):  
Vincent Bretagnolle ◽  
Julien Terraube
Keyword(s):  
Climate Change ◽  
Species Interactions ◽  
Experimental Studies ◽  
Trophic Levels ◽  
Generalist Predators ◽  
Top Down ◽  
Predator Prey ◽  
Key Topics ◽  
Available Information

Climate change is likely to impact all trophic levels, although the response of communities and ecosystems to it has only recently received considerable attention. Further, it is expected to affect the magnitude of species interactions themselves. In this chapter, we summarize why and how climate change could affect predator–prey interactions, then review the literature about its impact on predator–prey relationships in birds, and provide prospects for future studies. Expected effects on prey or predators may include changes in the following: distribution, phenology, population density, behaviour, morphology, or physiology. We review the currently available information concerning particular key topics: top-down versus bottom-up control, specialist versus generalist predators, functional versus numerical responses, trophic cascades and regime shifts, and lastly adaptation and selection. Finally, we focus our review on two well-studied bird examples: seabirds and raptors. Key future topics include long-term studies, modelling and experimental studies, evolutionary questions, and conservation issues.

scholarly journals Diversity and coexistence are influenced by time‐dependent species interactions in a predator–prey system

2020 ◽  
Vol 23 (6) ◽  
pp. 983-993 ◽  
Author(s):  
Canan Karakoç ◽  
Adam Thomas Clark ◽  
Antonis Chatzinotas
Keyword(s):  
Species Interactions ◽  
Time Dependent ◽  
Predator Prey ◽  
Prey System

scholarly journals Consumption of Atlantic Salmon Smolt by Striped Bass: A Review of the Predator–Prey Encounter and Implications for the Design of Effective Sampling Strategies

Fishes ◽  
2019 ◽  
Vol 4 (4) ◽  
pp. 50
Author(s):  
Andrews ◽  
Hirtle ◽  
Linnansaari ◽  
Curry
Keyword(s):  
Atlantic Salmon ◽  
Striped Bass ◽  
Species Interactions ◽  
Morone Saxatilis ◽  
Sampling Strategies ◽  
Native Range ◽  
Spawning Period ◽  
Predator Prey ◽  
Salmon Smolt ◽  
Future Management

The native striped bass (Morone saxatilis) population of the Miramichi River, New Brunswick is undergoing an unprecedented recovery while Atlantic salmon (Salmo salar) numbers within that system continue to decline. Atlantic salmon smolt depart from the Miramichi system during the striped bass spawning period and it is hypothesized that elevated striped bass abundances will increase encounter rates and predation on smolts. We summarize all available striped bass diet studies occurring within the native range of Atlantic salmon and present a review of the feeding behavior and diet preferences of striped bass before, during, and after their spawning period. The key studies vary in methodologies and interpretability. We present a standardized approach for assessing striped bass predation threats and smolt vulnerability and thus an improved understanding of the species interactions to guide future management in the Miramichi River.

Spatial and temporal variation in the infracommunity structure of helminths of Apodemus sylvaticus(Rodentia: Muridae)

Parasitology ◽  
1989 ◽  
Vol 98 (1) ◽  
pp. 145-150 ◽  
Author(s):  
S. S. J. Montgomery ◽  
W. I. Montgomery
Keyword(s):  
Species Richness ◽  
Northern Ireland ◽  
Population Density ◽  
Resource Utilization ◽  
Species Interactions ◽  
Apodemus Sylvaticus ◽  
Host Population ◽  
Spatial And Temporal Variation ◽  
Time And Space ◽  
Animal Material

SummaryMean species richness and diversity of the helminth infracommunity of Apodemus sylvaticus in woodland areas of Co. Down, Northern Ireland, varied in time and space. Variation in infracommunity structure among individual hosts, however, always accounted for more than 60% of the variation in the data from different places or different times. Helminth species richness increased with increasing population density, the percentage of the host population 16 weeks old or older, and the proportion of the host population with animal material in their stomachs, at two sites monitored over 33 months. The basis for spatial variation in infracommunity structure is less certain but host dynamics and differences in diet are likely to play some role. It is concluded that analysis at the infracommunity level focuses closely on the potential for species interactions and overlap in resource utilization. Infracommunity structure, at least in the case of A. sylvaticus, varies markedly in time and space and between individual hosts. Such variation should not be ignored in comparative studies.

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