Meeting Abstract
Fungal diseases have emerged as a major conservation concern in recent years. The energetic cost of coping with fungal infections competes seasonally with allocation towards life-history functions directly related to reproductive success. Such trade-offs could be reflected in circulating levels of hormones that mediate energy mobilization and reproduction in males and females. Establishing such relationships can be valuable both in terms of elucidating disease impacts and in establishing the significance of circulating hormones in conservation and management. We used a population of pygmy rattlesnakes afflicted with snake fungal disease (SFD) to examine energetic trade-offs and their endocrine basis. Specifically, we used flow-through respirometry to establish the metabolic cost of coping with SFD. We also monitored seasonal corticosterone, testosterone (males), and estradiol (females) in relation to infection status over the course of two years. Infected snakes had significantly elevated resting metabolic rates compared to uninfected snakes. Additionally, infected snakes had elevated corticosterone and lower testosterone and estradiol compared to uninfected snakes. Relationships between infection and reproductive hormones were only apparent during seasonal periods of significant reproductive investment in males and females. Results are consistent with the hypothesis that coping costs associated with SFD force allocation of resources away from processes directly related to current reproductive success and that trade-offs are mediated by adrenal and gonadal steroids.
