Meeting Abstract

P1.63  Saturday, Jan. 4 15:30  Effects of an immune response on reproduction and appetite in the red-sided garter snake (Thamnophis sirtalis parietalis) UHRIG, E.J.*; FRIESEN, C.R.; MASON, R.T.; Oregon State University, Corvallis; University of Sydney, Australia; Oregon State University, Corvallis uhrige@science.oregonstate.edu

Mounting an immune response, typically a costly endeavor for an organism, can have physiological implications of its own that are independent of the direct effects of the infection. Fever, lethargy and loss of appetite, for example, commonly occur as part of the immune response for many organisms. In addition, as organisms generally have a finite pool of resources to allocate to biological processes, an elevated immune response may lead to reduced investment in other costly processes such as reproduction. To date, despite the red-sided garter snake (Thamnophis sirtalis parietalis) being the focus of numerous studies of reproductive physiology and behavior, endocrinology, and chemical ecology, the effects of their immune response have not been extensively studied. Here, we present a study in which male and mated female red-sided garter snakes were injected with lipopolysaccharide (LPS) over the course of ten weeks. LPS is a non-pathogenic compound extracted from E.coli bacteria and is able to elicit an immune response when injected. To investigate potential effects of an immune response on reproductive investment, for females, we analyzed litter size and sex ratio, as well as offspring size and weight. For males, we determined testes masses and sperm counts. All snakes were weighed weekly before and after feeding. We found evidence suggesting that an immune response alters appetite in female snakes, but these effects may be mediated by reproductive state.