The evolution of coexistence: Reciprocal adaptation promotes the assembly of a simple community

Abstract

Species coexistence may result by chance when co-occurring species do not strongly interact or it may be an evolutionary outcome of strongly interacting species adapting to each other. Although patterns like character displacement indicate that coexistence has often been an evolutionary outcome, it is unclear how often the evolution of coexistence represents adaptation in only one species or reciprocal adaptation among all interacting species. Here, we demonstrate a strong role for evolution in the coexistence of guppies and killifish in Trinidadian streams. We experimentally recreated the temporal stages in the invasion and establishment of guppies into communities that previously contained only killifish. We combined demographic responses of guppies and killifish with a size-based integral projection model to calculate the fitness of the phenotypes of each species in each of the stages of community assembly. We show that guppies from locally adapted populations that are sympatric with killifish have higher fitness when paired with killifish than guppies from allopatric populations. This elevated fitness involves effects traceable to both guppy and killifish evolution. We discuss the implications of our results to the study of species coexistence and how it may be mediated through eco-evolutionary feedbacks.

Landscape patterns in top‐down control of decomposition: omnivory disrupts a tropical detrital‐based trophic cascade

“…Additionally, the presence of guppies has been shown to reduce killifish growth rates while not affecting survival in a field reciprocal transplant experiment (Walsh et al. ) and in a mesocosm experiment (Bassar ). Thus, interactions between guppies and killifish are likely both predatory and competitive in nature and, as such, their relationship may best be described as intraguild predation.…”

“…The exact mechanisms causing killifish density to decline in the presence of guppies remains unknown; however, Fraser and Lamphere (2013) reported that guppies readily consume killifish eggs and neonates in the laboratory and that introduced guppies reduce killifish densities in a replicated field experiment. Additionally, the presence of guppies has been shown to reduce killifish growth rates while not affecting survival in a field reciprocal transplant experiment (Walsh et al 2011) and in a mesocosm experiment (Bassar 2017). Thus, interactions between guppies and killifish are likely both predatory and competitive in nature and, as such, their relationship may best be described as intraguild predation.…”

Digest: Fitness gains in guppies support evolution's role in coexistence*

“…In response to changes in killifish presence, the guppies rapidly evolve differences in color, behavior, and life-history traits (see, e.g., Reznick and Endler 1982). Similarly, killifish lifehistory traits repeatedly diverge between natural ponds with and without guppies (Walsh and Reznick 2009).Using this model system, Bassar et al (2016) seek to address whether the observed changes in guppies and killifish promote * This manuscript corresponds to Bassar, R. D., Simon, T., Roberts, W., Travis, J., and Reznick, D. N. 2016. The evolution of coexistence: reciprocal adaptation promotes the assembly of a simple community.…”

“…Using this model system, Bassar et al (2016) seek to address whether the observed changes in guppies and killifish promote * This manuscript corresponds to Bassar, R. D., Simon, T., Roberts, W., Travis, J., and Reznick, D. N. 2016. The evolution of coexistence: reciprocal adaptation promotes the assembly of a simple community.…”

“…Using this model system, Bassar et al (2016) seek to address whether the observed changes in guppies and killifish promote * This manuscript corresponds to Bassar, R. D., Simon, T., Roberts, W., coexistence. The authors find that guppies evolve not only in response to interactions with killifish, but also in response to phenotypes of killifish-a prerequisite for coevolution, which is consistent with previous observations of guppies shifting their diet and reducing niche overlap (Palkovacs et al 2009;Bassar et al 2010).…”