Meeting Abstract
P3.82 Sunday, Jan. 6 Sexual dimorphisms in behavior in two long-snouted Anolis lizard species ROBINSON, C.D.*; SANGER, T.J.; BATTLES, A.C.; JOHNSON, M.A.; Trinity University, San Antonio, TX; Harvard University, Cambridge, MA; Trinity University, San Antonio, TX; Trinity University, San Antonio, TX crobins3@trinity.edu
Sexual dimorphisms can evolve as the result of sexual selection or because of natural selection that enhances ecological differences between the sexes. In this study, we examined the behavior and ecology of two species of Anolis lizards, A. maynardi in Cayman Brac, and A. brunneus in Crooked Island, Bahamas, to assess factors that may influence the evolution of their remarkably long male snouts. These long snouts could have evolved via female choice, if females exhibit some preferences for longer male snouts, or through male-male competition, if longer snouts result in social dominance. Alternatively, sexual dimorphism in snout length may have evolved if the sexes utilize different habitats in which different prey capture techniques depend on the shape of the snout. Using behavioral arena trials to assess the hypotheses of sexual selection, we found that A. maynardi males with shorter snouts were somewhat more likely to be dominant over longer-snouted males, but females tended to prefer to associate with males with longer snouts. Conversely, in A. brunneus, male dominance was not associated with snout length, and females tended to associate with the shorter-snouted males. Thus, the evidence for snout length evolving via sexual selection is weak. Further, field data showed that males and females of both species utilize very similar microhabitats, as measured by perch height and diameter. However, in both species, females performed active foraging for insect prey more frequently than males, who relied more on a sit-and-wait foraging strategy. Together, these data suggest that foraging differences between the sexes may be a more likely explanation for the evolution of sexually-dimorphic snout length than sexual selection.
