Meeting Abstract

47.2  Tuesday, Jan. 5  Male aggression and territoriality in recently diverged populations of desert lizards ROBERTSON, Jeanne M*; ROSENBLUM, Erica Bree; Univ. of Idaho, Moscow; Univ. of Idaho, Moscow jmrobertson@uidaho.edu

Models of ecological speciation focus on the reproductive isolation of ecologically divergent populations. However, the diversification of male territorial behavior in incipient species is largely unexamined, despite that resource acquisition and defense is critical to male reproductive success. White Sands in southwestern New Mexico is a geologically young formation (~ 6000 yrs) of stark white sand dune surrounded by Chihuahuan desert habitat. Multiple species, including our focal taxon, the Western Fence Lizard (Sceloporus undulatus) exhibit cryptic (blanched) dorsal coloration that distinguishes it from the dark coloration of the surrounding desert scrub populations. Male fence lizards also show strong divergence in social signal coloration, suggesting a role for both natural and sexual selection in this system. The white sands lizards are thus an ideal system to investigate the divergence in intersexual competition as a cause or consequence of ecologically speciation. We examined male-male aggressive and territorial behavior to determine whether males of recently diverged populations (white sands versus desert scrub) can discriminate between local and non-local conspecifics and whether territorial males are more aggressive towards local males. We found that males in both populations can discriminate between intruder male phenotypes, but that the effect and direction of aggression differed between sites. As predicted, white sands males were more aggressive to local males while desert scrub males showed higher levels of aggression toward non-local males. We also found surprising shifts in the composite behavior of territorial males. This study underscores the significance of male-male interactions in the early stages of divergence.