Local adaptation in Trinidadian guppies alters ecosystem processes

Abstract

Theory suggests evolutionary change can significantly influence and act in tandem with ecological forces via ecological-evolutionary feedbacks. This theory assumes that significant evolutionary change occurs over ecologically relevant timescales and that phenotypes have differential effects on the environment. Here we test the hypothesis that local adaptation causes ecosystem structure and function to diverge. We demonstrate that populations of Trinidadian guppies (Poecilia reticulata), characterized by differences in phenotypic and population-level traits, differ in their impact on ecosystem properties. We report results from a replicated, common garden mesocosm experiment and show that differences between guppy phenotypes result in the divergence of ecosystem structure (algal, invertebrate, and detrital standing stocks) and function (gross primary productivity, leaf decomposition rates, and nutrient flux). These phenotypic effects are further modified by effects of guppy density. We evaluated the generality of these effects by replicating the experiment using guppies derived from two independent origins of the phenotype. Finally, we tested the ability of multiple guppy traits to explain observed differences in the mesocosms. Our findings demonstrate that evolution can significantly affect both ecosystem structure and function. The ecosystem differences reported here are consistent with patterns observed across natural streams and argue that guppies play a significant role in shaping these ecosystems.ecological-evolutionary feedbacks | intraspecific variation | ecosystem function E cosystem ecologists commonly view populations as homogeneous biomass pools in which individuals operate in identical ways to influence nutrient and energy flows (1). Individual organisms can influence ecosystem processes by altering their body size (material storage), changing their consumption and excretion characteristics (material flux) (2), modifying their internal stoichiometry (3), or physically altering their habitat (4, 5). Differences among individuals can, via natural selection, become converted into differences among populations and, hence, in the impact of a locally adapted population on the structure of its ecosystem. Furthermore, empirical evidence suggests the evolution of organismal traits that can affect habitat utilization happens on timescales similar to ecological processes (6). One possible consequence of rapid evolutionary change is that it can change ecological dynamics and set up feedbacks between ecological and evolutionary processes (7-9). Central to this hypothesis is the assumption that phenotypic variation translates into variation in how individuals and populations impact their environment (10).Prior research has already established the links between ecology and evolution. Laboratory studies focused on a model predator-prey interaction demonstrated that evolution of the prey population significantly altered the nature of predator-prey cycles (9). Evidence from natural or seminatural settings have shown t...

Testing for local host–parasite adaptation: an experiment with Gyrodactylus ectoparasites and guppy hosts

“…When no Gyrodactylus were seen on a fish over three consecutive days of visual inspection (as above), the fish was considered parasite-free. Elastomer dyes (Northwest Marine Technology Inc., U.S.A.) were then injected to give each fish a distinct intra-dermic mark, a procedure used effectively in many previous guppy studies (Bassar et al, 2010;Weese et al, 2010;Pérez-Jvostov et al, 2012). The elastomer marks were no longer than 2 mm and no marked fish showed signs of reduced mobility or altered behaviour.…”

“…This natural flow allowed colonisation of the mesocosms by algae and invertebrates, including natural foods for guppies, but excluded any non-experimental guppies. These specific mesocosms have been used in a number guppy studies and are a good mimic of natural conditions (for technical specifications see Palkovacs et al, 2009;Bassar et al, 2010;Pérez-Jvostov et al, 2012).…”

Adaptive genetic variation mediates bottom-up and top-down control in an aquatic ecosystem

“…Emerging interest in eco-evolutionary dynamics has resulted in a growing number of studies documenting the ways by which evolution can influence population dynamics [1][2][3], community assembly [4][5][6][7] and ecosystem function [8]. A critical component of the eco-evolutionary framework is to determine how phenotypic variation from local adaptation affects the way individuals and populations interact with their biotic and abiotic environment [5].…”

“…Local adaptation, or the evolution of traits that provide an advantage under local environmental conditions, is a key mode by which evolution shapes contemporary ecological dynamics [5,[8][9][10]. To date, the best case studies detailing the ecological consequences of evolution stem from local adaptation in predators and subsequent shifts in trophic cascades [5,9,11]. For example, species pairs of a predatory fish, three-spined stickleback (Gasterosteus aculeatus; hereafter stickleback), which have repeatedly evolved into sympatric benthivorous and zooplanktivorous ecotypes, cause shifts in the structure of the zooplankton community and alter light availability in a mesocosm environment [8].…”

“…A critical component of the eco-evolutionary framework is to determine how phenotypic variation from local adaptation affects the way individuals and populations interact with their biotic and abiotic environment [5]. Local adaptation, or the evolution of traits that provide an advantage under local environmental conditions, is a key mode by which evolution shapes contemporary ecological dynamics [5,[8][9][10]. To date, the best case studies detailing the ecological consequences of evolution stem from local adaptation in predators and subsequent shifts in trophic cascades [5,9,11].…”