Meeting Abstract

59.6  Wednesday, Jan. 6  Testosterone and latitude in reptiles and amphibians MOORE, I.T.*; VALIN, M.; CASASANTA, M.; EIKENAAR, C.; HUSAK, J.F.; Virginia Tech; Virginia Tech; Virginia Tech; Virginia Tech; University of South Dakota itmoore@vt.edu

Latitudinal variation in life history characteristics has long been the focus of ecologists. One of the best examples has been latitudinal variation in clutch size with tropical vertebrates laying fewer eggs and having smaller litters than higher latitude species. More recently physiologists have also described latitudinal variation in a variety of processes that suggest tropical organisms exhibit a slower pace of life than their higher latitude counterparts. One prominent example has been the description of latitudinal variation in testosterone levels in birds. There is a positive relationship between testosterone and latitude in birds with tropical species typically having lower levels than higher latitude species. Similarly, a positive relationship between testosterone and altitude also exists in birds. However, it is unclear if these relationships are a direct result of abiotic factors associated with latitude and altitude or are rather associated with social factors such as mating system and degree of paternal care. It is also unclear if such a relationship exists in other groups of vertebrates. We are investigating if there is a relationship between testosterone and latitude and altitude in both reptiles and amphibians. Reptiles, in particular, have much less variety in mating systems than birds and thus provide an opportunity to investigate if the relationships between environmental factors and testosterone are direct or associated with related social factors. If similar relationships exist between testosterone and latitude and altitude in a variety of taxa, this suggests that environmental factors may be a stronger determinant of testosterone levels than social factors.