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1. Predator hunting modes and predator–prey space games

   https://doi.org/10.1111/eth.12998  

   Luttbeg, Barney ; Hammond, John_I ; Brodin, Tomas ; Sih, Andrew ; Wright, ed., Jonathan ( December 2019 , Ethology)

   Predators and prey are often engaged in a game where their expected fitnesses are affected by their relative spatial distributions. Game models generally predict that when predators and prey move at similar temporal and spatial scales that predators should distribute themselves to match the distribution of the prey's resources and that prey should be relatively uniformly distributed. These predictions should better apply to sit‐and‐pursue and sit‐and‐wait predators, who must anticipate the spatial distributions of their prey, than active predators that search for their prey. We test this with an experiment observing the spatial distributions and estimating the causes of movements between patches for Pacific tree frog tadpoles (Pseudacris regilla), a sit‐and‐pursue dragonfly larvae predator (Rhionaeschna multicolor), and an active salamander larval predator (Ambystoma tigrinum mavortium) when a single species was in the arena and when the prey was with one of the predators. We find that the sit‐and‐pursue predator favors patches with more of the prey's algae resources when the prey is not in the experimental arena and that the prey, when in the arena with this predator, do not favor patches with more resources. We also find that the active predator does not favor patches with more algae and that prey, when with an active predator, continue to favor these higher resource patches. These results suggest that the hunting modes of predators impact their spatial distributions and the spatial distributions of their prey, which has potential to have cascading effects on lower trophic levels.

    

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2. Changes in prey body size differentially reduces predation risk across predator and prey abundances

   https://doi.org/10.1111/oik.09933  

   Hammill, Edd ; Hancey, Kayla ; Cortez, Michael ( April 2023 , Oikos)

   Subject Editor: Gregor Kalinkat Editor-in-Chief: Dries Bonte (Ed.)

   Trophic interactions underpin the structure of ecological communities by describing the rates at which consumers exploit their resources. The rates at which predators consume their prey are influenced by prey traits, with many species inducing defensive modifications to prey traits following the threat of predation. Here we use different clonal lines of the protist Paramecium being consumed by Stenostomum predators to highlight how differences in prey traits impact rates of predation. Clonal lines differed in their body width traits, and in their ability to induce changes in body width. By using a factorial cross of predator and prey abundances for different clonal lines we demonstrate how evolutionary or induced alterations in prey traits can impact the relative threat of predation. Our experiments show how interference among predators impacts predation rate, and how increased body width increased predator handling times. Given that reductions in the strength of interspecific interactions are associated with increased levels of overall community stability, our results indicate how individual level changes may scale up to impact whole communities 

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3. Predator–prey interactions of terrestrial invertebrates are determined by predator body size and species identity

   https://doi.org/10.1002/ecy.3634  

   Miller‐ter Kuile, Ana ; Apigo, Austen ; Bui, An ; DiFiore, Bartholomew ; Forbes, Elizabeth S. ; Lee, Michelle ; Orr, Devyn ; Preston, Daniel L. ; Behm, Rachel ; Bogar, Taylor ; et al ( March 2022 , Ecology)

   Predator–prey interactions shape ecosystems and can help maintain biodiversity. However, for many of the earth's most biodiverse and abundant organisms, including terrestrial arthropods, these interactions are difficult or impossible to observe directly with traditional approaches. Based on previous theory, it is likely that predator–prey interactions for these organisms are shaped by a combination of predator traits, including body size and species‐specific hunting strategies. In this study, we combined diet DNA metabarcoding data of 173 individual invertebrate predators from nine species (a total of 305 individual predator–prey interactions) with an extensive community body size data set of a well‐described invertebrate community to explore how predator traits and identity shape interactions. We found that (1) mean size of prey families in the field usually scaled with predator size, with species‐specific variation to a general size‐scaling relationship (exceptions likely indicating scavenging or feeding on smaller life stages). We also found that (2) although predator hunting traits, including web and venom use, are thought to shape predator–prey interaction outcomes, predator identity more strongly influenced our indirect measure of the relative size of predators and prey (predator:prey size ratios) than either of these hunting traits. Our findings indicate that predator body size and species identity are important in shaping trophic interactions in invertebrate food webs and could help predict how anthropogenic biodiversity change will influence terrestrial invertebrates, the earth's most diverse animal taxonomic group.

    

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4. Bacterial communities in carnivorous pitcher plants colonize and persist in inquiline mosquitoes

   https://doi.org/10.1186/s42523-022-00164-1  

   Arellano, Aldo A. ; Coon, Kerri L. ( February 2022 , Animal Microbiome)

   The leaves of carnivorous pitcher plants harbor diverse communities of inquiline species, including bacteria and larvae of the pitcher plant mosquito (Wyeomyia smithii), which aid the plant by processing captured prey. Despite the growing appreciation for this microecosystem as a tractable model in which to study food web dynamics and the moniker ofW. smithiias a ‘keystone predator’, very little is known about microbiota acquisition and assembly inW. smithiimosquitoes or the impacts ofW. smithii-microbiota interactions on mosquito and/or plant fitness.

   In this study, we used high throughput sequencing of bacterial 16S rRNA gene amplicons to characterize and compare microbiota diversity in field- and laboratory-derivedW. smithiilarvae. We then conducted controlled experiments in the laboratory to better understand the factors shaping microbiota acquisition and persistence across theW. smithiilife cycle. Methods were also developed to produce axenic (microbiota-free)W. smithiilarvae that can be selectively recolonized with one or more known bacterial species in order to study microbiota function. Our results support a dominant role for the pitcher environment in shaping microbiota diversity inW. smithiilarvae, while also indicating that pitcher-associated microbiota can persist in and be dispersed by adultW. smithiimosquitoes. We also demonstrate the successful generation of axenicW. smithiilarvae and report variable fitness outcomes in gnotobiotic larvae monocolonized by individual bacterial isolates derived from naturally occurring pitchers in the field.

   This study provides the first information on microbiota acquisition and assembly inW. smithiimosquitoes. This study also provides the first evidence for successful microbiota manipulation in this species. Altogether, our results highlight the value of such methods for studying host-microbiota interactions and lay the foundation for future studies to understand howW. smithii-microbiota interactions shape the structure and stability of this important model ecosystem.

    

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5. Exploratory behaviour and novel predator recognition: behavioural correlations across contexts

   https://doi.org/10.1111/jfb.12995  

   Blake, C. A. ; Gabor, C. R. ( May 2016 , Journal of Fish Biology)

   It was hypothesized that the exploratory behaviour of an individual measured in a novel environment could predict its behaviour in response to a novel predator. This study examined novel predator recognition in the western mosquitofishGambusia affinis, a species with individual differences in risk‐taking, activity and exploration in novel environments. Prey responded with characteristic shoaling and avoidance in response to native predators, but did not show characteristic antipredator behaviour towards novel predators. Furthermore,G. affinisexhibited individual‐level behavioural correlations across contexts but only when prey were tested with native predators. This could be the result of native predatory selection on behavioural correlations in the prey species.

    

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