Meeting Abstract
P1.100 Sunday, Jan. 4 Population Divergence and Sexual Asymmetry of Visual Performance in Sceloporus undulatus Lizards at the White Sands Ecotone. NAVA, S. S.; Indiana University and the Center for the Integrative Study of Animal Behavior snava@indiana.edu
In animal communication, the sensory drive model predicts that visual signals evolve to match the visual abilities of receivers, which in turn are shaped by the physical conditions of the environment. Thus, when populations of animals live in habitats that differ in visual conditions, the visual systems of individuals from those populations may diverge, and in turn guide the coevolution of signals and visual performance. This coevolution may also depend on the strength of differential selection on the sexes, e.g., if sexual selection acts strongly and independently on both sexes, phenotypic evolution can be accelerated. When the sexes have been subjected to different selective pressures, they may not only be sexually-dimorphic in phenotype, but also in the underlying genetic, morphological, and physiological mechanisms that produce those phenotypes. Different mechanisms are likely to yield different adaptive responses to subsequent selective pressures and hence slow or accelerate the sensory drive process and its effect on population divergence and evolution. Here, I tested for population and sex differences in visual performance in the sexually dimorphic Sceloporus undulatus lizards that have evolved adaptive dorsal coloration in three extremely divergent habitat types (white sand dunes, black lava rocks, and desert scrub). I show that morphs from the three habitats differ in spectral sensitivity to the blue color exhibited by males. I also find that males and females differ in their ability to detect the blue color. Specific data and results will be presented. These findings suggest that visual performance may evolve quickly and diverge between the sexes and that the sensory drive process may be best described as the repeated co-evolution between signals and receiver sensory systems.
