CAREER: Testing alternative routes of adaptive phenotype-environment matching across heterogeneous landscapes in wild populations

Auburn University, Auburn AL

Investigators

Abstract

This research will examine how animals adjust to environmental variation across different life stages by focusing on a small lizard species that lays eggs in diverse habitats. Environmental conditions vary at small spatial scales (for example, moving between sunny and shady patches), which can present challenges to organisms that are adapted to specific conditions. Plants and animals have strategies that allow them to cope with this variation, and it is important for scientists to understand how such strategies are deployed so responses to environmental changes can be better predicted. The goals of this project are to 1) quantify the strength of natural selection acting on the way embryos develop in response to environmental variation, 2) determine if newly-hatched offspring seek suitable habitat, and 3) examine whether mothers select nest sites with conditions that have life-long benefits for their offspring. Understanding these three different ways of dealing with environmental variation will help ecologists predict how animals will respond to environmental change. This project also aims to improve science education in Alabama by creating a summer fellowship program for middle school teachers. Teachers will conduct research and develop lesson plans for their classrooms to better prepare them to teach science as a process. Teacher fellows will also mentor middle school students in science fair projects, which in turn, will enhance science literacy in schools that are under-served in science education. Natural selection has favored several routes that enable organisms to overcome challenges imposed by heterogeneous environments. First, plastic responses to the environment can modify phenotypes so that they are suited to the surrounding environment (Environmental Matching Hypothesis). Second, rather than the environment shaping an individual’s phenotype, individuals can actively seek environments that are suited to their phenotype (Matching Habitat Choice Hypothesis). Third, parents can select specific microhabitats that shield their developing offspring from environmental variation, thereby exposing them to “good” developmental environments that have life-long positive effects (Silver Spoon Hypothesis). These strategies can maximize fitness in heterogeneous environments at different life stages (via embryo responses, post-natal habitat choice, or parental behavior). However, despite many empirical studies of each hypothesis, most do not simultaneously consider these explanations as alternate or interactive routes that influence the evolution of developmental plasticity. The goals of this project are to (1) test these alternative hypotheses for how organisms deal with environmental heterogeneity, and (2) empirically quantify selection on developmental reaction norms in wild populations and identify behaviors that facilitate or limit the evolution of plasticity. This research will integrate laboratory and field studies of brown anole lizards that inhabit islands that vary in habitat structure and ambient conditions. The integration of novel lab and field approaches will set new standards for empirical studies of selection on plasticity, and the consequences of matching habitat choice and maternal nesting behaviors in the wild. Overall, this work will provide an integrative assessment of how organisms deal with environmental heterogeneity in nature. 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.