Evolution of Maternal Effects in a Model Avian System

University Of Arizona, Tucson AZ

Investigators

Abstract

A central tenet of evolutionary biology is that natural selection leads to adaptation. Studies of house finches in Montana and Alabama have documented that indeed, these birds have rapidly adapted to the local environment, despite having colonized these highly ecologically distinct areas only in the last few decades. Local adaptations include different sizes and shapes for males and females but these changes have occurred too rapidly to be explained by genetically based changes alone. It has been documented previously that rapid changes in how male and female house finches grow and develop in Montana and Alabama are responsible for differences between the populations. In particular it is the allocation of males and females to different positions in the laying order and strong and sex-specific effects of laying order on growth and development that led to rapid changes in the populations. How such maternal effects can affect the growth of males and females is the focus of this study. This investigation will test whether female allocation of hormones such as testosterone and prolactin, specific nutrients such as carotenoids and lipids, overall nutrient content of eggs, or the timing of egg incubation varies across laying order and how each of these factors affects the growth and development of male and female offspring. Our investigation is fundamental to a better understanding of how natural selection can lead to rapid adaptation to local environments. The ability to adjust the growth patterns of males and females as an adaptation to local environments may have enabled the house finch and some other invasive vertebrate species to colonize highly distinct and changing environments.