The evolution of anticipatory maternal effects versus maternal condition transfer effects in Trinidadian killifish

It has long been known that changes in the environment can influence the ability of mothers to provision their offspring. Therefore, when should mom evolve to anticipate a change in the environment to best provision her offspring? This research will address this question by testing hypotheses regarding the ecological conditions that drive maternal offspring provisioning strategies. The work focuses on Trinidadian killifish, which exhibit maternal provisioning strategies that are easy to quantify. Additionally, killifish experience a wide range of ecological conditions. Finally, killifish are easy to manipulate, allowing for experimental tests of how natural selection influences offspring provisioning. Therefore, this research is well-positioned to provide new insights into how and why maternal provisioning strategies evolve. The work has broad implications for understanding the mechanisms by which organisms respond to environmental change. Further, it will improve researchers’ ability to forecast how species respond to environmental stressors. The research goals will be combined with a plan for broader impacts that that uses killifish as a model to improve teaching, engage undergraduates from underrepresented groups in research at a Hispanic serving institution, and provide public outreach. Much research has explored whether mothers respond to predictable shifts in environmental signals by modifying offspring phenotypes to best match future conditions. Yet, there is little evidence for the existence of such ‘anticipatory maternal effects’. This shows that our understanding of the evolution of maternal effects is incomplete. 'Maternal condition transfer effects' represents an alternative to anticipatory effects that occur when the environment experienced by females during development influences offspring fitness. These effects are not driven by external signals but are instead a byproduct of past environmental quality. Condition transfer effects have received far less attention that anticipatory effects but are likely quite widespread. Interestingly, little work has considered the conditions that favor the evolution condition transfer vs. anticipatory effects. This project will use populations of killifish on the island of Trinidad to pursue three central goals. The research will: (1) determine if predator-mediated divergence in resource availability favors evolutionary shifts in maternal effects (i.e., condition transfer vs. anticipatory effects). (2) Test the connection between divergent natural selection, maternal condition, and offspring fitness via ‘offspring outplant experiments’. (3) Experimentally evaluate the influence of resource availability on the evolution of maternal effects via long-term perturbations performed in natural streams. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.