Meeting Abstract

P3.137  Jan. 6  Elevation and testosterone in tropical rufous-collared sparrows (Zontrichia capensis ) CLASS, A.M.*; MOORE, I.T.; Virginia Tech; Virginia Tech classam@vt.edu

Substantial data exists on the behavioral endocrinology of temperate birds, yet we are just beginning to examine and compare tropical to temperate systems. In a recent comparative study, tropical birds had lower mean peak testosterone levels on average than temperate birds. Nevertheless several tropical species in the study had comparable or higher peak testosterone levels than temperate species. In contrast, in a study of peak testosterone levels in three species of the genus Zonotrichia, distributed from the arctic to the equator, the tropical Zonotrichia had the highest peak testosterone levels. Despite phylogenetic control within the Zonotrichia genus, the tropical population studied was at high elevation, while the temperate and arctic populations were at low elevation. To investigate the effect of elevation on testosterone of tropical Zonotrichia, we compare peak testosterone levels of the rufous-collared sparrow, Zonotrichia capensis, existing at two elevations, but the same latitude in the Andes of central Ecuador. We hypothesize that higher elevation populations of Z. capensis will have higher mean peak testosterone levels. Though tropical endocrine research still lags behind temperate endocrinology, by focusing research on tropical species with temperate congeners we can begin to compare ecological systems.