Gerlinde Höbel
Department of Biological Sciences, UW-Milwaukee, hoebel@uwm.edu
Gray treefrogs (Hyla versicolor) have amazing color change ability, and can range from dark brown to bright green. Yet, nothing is known about the distribution of body color in nature, or whether frogs choose their resting perches based on their body color, or adjust body color as a function of ambient color or temperature. Here, we examine the behavioral ecology of color change in gray treefrogs. Color change can function to hide the individual from predators (crypsis), or to make the individual obvious for conspecifics (conspicuousness). In addition, in ectotherms (cold blooded animals), body color may help with thermoregulation (darker colors heat up better, brighter colors increase reflection and stay cooler). We took pictures and temperature measurements from (i) calling males at the pond at night, and (ii) male and female frogs resting during the day. The daytime pictures were taken from frogs released in a large enclosure fitted with branches and foliage (treefrogs spend the day resting in the tree canopy, making it impossible to sample frog body color in nature). We will analyze color and contrast measures from the frogs to test whether temperature or background color is a better predictor of frog body color