Lake Forest College, Biology, Lake Forest, IL 60045
Studies of guppy sexual behavior have demonstrated female mating preferences for males with more orange coloration, and also for males with color patterns that are unique rather than common in a population. The latter result, however, was obtained by observing females already familiar with males in their aquarium. I asked whether similar results would be obtained if data on female sexual responsiveness were collected the first time these virgins were introduced to the males. If so, then naïve virgin females should respond less to males with similar color patterns and show more interest in unique males, regardless of other characteristics of their color pattern. I observed the initial reaction of virgin female guppies when placed in a tank with two “redundant” (similar color pattern) and two unique (both with different color pattern) males. I wanted to see whether a female would immediately distinguish between redundant and unique males, in responding to their courtship displays. Three tanks were set up, each with four males from three different full sib families: two brothers with similar (redundant) color patterns and two unrelated unique males. The redundant pair of males was drawn from a different family in each of the three tanks. Six non-virgin females were included in each tank to reduce harassment by males. Each virgin was observed for thirty minutes, recording her responses to male sexual displays. Responses to displays were measured on a scale from 1-5, where 1 represented least responsive behavior, while 5 represented successful mating of male and virgin female. Virgin females were more responsive to males from two of the families than to the third regardless of whether they were redundant or unique. These results indicate that female guppies may require a period of familiarization before they begin to discriminate between males with unique and common (redundant) color patterns.
[Abstract (DOC)]