Meeting Abstract
The ability to navigate around an individual’s habitat and is necessary for territoriality, mate choice, and acquisition of food resources. In many species, males exhibit superior spatial navigation abilities than females. This sexual dimorphism suggests this difference may be due to testosterone. Testosterone increases territorial behavior and home range size, thus, it may also affect the brain region associated with spatial memory. In reptiles, the medial and dorsal cortices are involved in spatial memory and these brain regions have been found to be larger in animals with larger territories. We hypothesize that testosterone affects home range size, cortical volumes, and neurogenesis in these brain regions. Western fence lizards were captured, marked, and castrated. Subjects were then implanted with either testosterone-filled or blank silastic capsules. After returning subjects to their initial capture site, individuals were located approximately ever other day to determine home range size. In addition, a control group not subjected to the surgical treatment was captured, marked, and re-sighted. After approximately a month, individuals were recaptured and sacrificed. Brain tissue was analyzed to determine volumes of cortical regions. Neither medial nor dorsal cortical volumes were affected by treatment. However, cortical volumes may be affected by home range size directly and it is possible testosterone treatment didn’t affect home range size during this experiment. These results will help determine testosterone’s role in not only regulating territorial behavior, but also in regulating growth of brain regions directly or indirectly by affecting territorial behaviors.
