AUTHOR=Amarasekare Priyanga 

TITLE=Ecological Constraints on the Evolution of Consumer Functional Responses

JOURNAL=Frontiers in Ecology and Evolution

VOLUME=Volume 10 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/ecology-and-evolution/articles/10.3389/fevo.2022.836644

DOI=10.3389/fevo.2022.836644

ISSN=2296-701X

ABSTRACT=Intrinsically generated oscillations are a defining feature of consumer-resource interactions.  They can have important consequences for the evolution of consumer functional responses.   Functional response traits that can maximize resource (consumer) fitness ---low (high) attack rates and long (short) handling times --- generate high-amplitude oscillations that can predispose species to extinction during periods of low abundances.  This suggests that the ecological consequences of consumer-resource oscillations may impede evolutionary outcomes that maximize fitness. Data suggest this to be a strong possibility.  Time series analyses reveal consumer-resource cycles to be infrequent in real communities, and functional response studies show a preponderance of low attack rates and/or short handling times that preclude oscillations but maximize neither species' fitness.  Here I present an eco-evolutionary model to address this tension between ecological dynamics and the evolution of functional response traits.  I show that the empirically observed attack rate-handling time distributions emerge naturally from the interplay between individual-level selection and the population-level constraint of oscillation-induced extinction. Extinction at low abundances curtails stabilizing selection towards trait values that maximize fitness but induce large-amplitude oscillations.  As a result, persistent interactions are those with low attack rates and/or short handling times. This finding suggests that differential persistence of genotypes with different attack rate - handling time combinations may act as an ecological constraint on the evolution of consumer functional responses.  It emphasizes the importance of incorporating oscillation-induced extinction into models that link food web topology to community persistence.