The Adaptive Potential of Maternal Stress as a Driver of Variation in Offspring Fitness in a Free-living Animal

This project addresses a question of fundamental importance to both the biological and medical fields; how does the stress a mother experiences impact her offspring? Specifically, this project examines how maternal stress alters the morphology, behavior and physiology of offspring, and how these changes ultimately affect offspring survival - in both highly stressful and benign environments. The scientists challenge the widely held belief that maternal stress negatively affects offspring. They propose that maternal stress prepares offspring for high stress conditions. This project tests, in lizards, whether offspring of stressed mothers will survive better in high stress environments (containing predatory, invasive fire ants), worse in low stress environments and if lizards that come from stressful environments are better able to deal with stress. By testing the consequences of exposure to novel predatory ants, this project addresses the global issue of the impacts of environmental change. The results work will inform the prediction and management of the imported red fire ant, which currently threatens the survival of many vertebrates in the southern USA. This work will leverage the strong community interest in these invasive fire ants to engage students and the community in science. The investigators will partner with the Girl Scouts of Southern Alabama and Park Forest Middle School in Pennsylvania to develop science related education tools involving both the local community and school-aged students.

Maternal stress is a driving factor affecting offspring phenotypes and is traditionally viewed as 'costly' to organismal fitness. This project tests the hypothesis that predator-induced maternal stress adaptively prepares offspring for the high-risk environment experienced by the mother. It examines whether offspring from stressed mothers survive better in high-risk environments and the potential mechanisms (morphology, physiology, and behavior) that may affect survival differences. The investigators will use a combination of laboratory manipulations, and natural and semi-captive field experiments using free-living fence lizards (prey) and fire ants (predator). Maternal and egg stress levels will be experimentally manipulated and resulting offspring phenotype measured before offspring are released into high or low predator risk environments and natural survival measured. By testing these assumptions in fence lizards captured from fire ant invaded and non-invaded sites, this project evaluates the influence of an evolutionary history of risk on the strength of these effects. This project will contribute to the understanding of the consequences of maternal stress for offspring fitness within evolutionary and ecologically relevant environments, and challenge the assumption that consequences of stress are necessarily negative. The proposed project addresses the globally-important issue of invasive red fire ants. Investigators will partner with the Girl Scouts of Southern Alabama and Park Forest Middle School in Pennsylvania, developing science related classroom activities, educating the local community and school-aged students. The proposed work supports the training of 1 Masters and 1 Doctoral student, 1 post-doctoral fellow, 4 undergraduates, and an early career scientist.