Understanding Maternal Effects in a Natural Population of a Long-Lived Organism

Iowa State University, Ames IA

Investigators

Abstract

In several major groups of vertebrate animals, offspring sex is determined permanently by environmental temperatures experienced during embryonic development. Little is understood about the importance of many aspects of this phenomenon (known as TSD). The roles of genetic and nongenetic maternal effects, like reproductive physiology and behavior under natural conditions, are particularly in need of critical evaluation. The proposed research will investigate several significant maternal aspects of the biology of TSD in a natural population of long-lived vertebrates that has been studied in detail since 1988: (1) the impact of maternally-derived yolk hormones and how such hormones might vary with maternal age, (2) the genetically inherited component of nesting behavior of females with TSD, and (3) the genetically inherited component of offspring sex determination under TSD. These questions will be addressed with a series of multi-year field and laboratory projects. A team of postdoctoral and student researchers will gather crucial new physiological, behavioral, and genetic data. The research team will study animals from a natural population during nesting events. Vegetation cover over nests, which accurately predicts offspring sex ratio, and nesting date will be recorded. Data will then be obtained for offspring sex ratio for each nest, and incubation temperature, yolk hormone levels in eggs, and offspring paternity for a focal subset of nests. The findings of this research will have important implications for the impacts of climate change and human habitat use on the biology and conservation of species with TSD. This research program will also provide extensive educational opportunities for numerous students (including underrepresented minorities, persons with disabilities, and women) and the public.