Meeting Abstract

85.4  Tuesday, Jan. 6  Pining for Pinups: the importance of color in mate choice of the blue crab Callinectes sapidus BALDWIN, J. L.*; JOHNSEN, S.; Duke Univ.; Duke Univ. jamie.baldwin@duke.edu

Despite the economic and ecological importance of the blue crab Callinectes sapidus, their vision has been little studied, particularly in regard to sexual signaling and mating behavior. While one study suggested that blue crab males select female mates based on the redness of their claws, most research has focused on the use of pheromones for mate attraction. We examined the responses of male crabs to photographs of females in submissive sexual postures with differently colored claws using binary choice experiments. Mature male blue crabs were collected from Jarretts Bay, North Carolina and transported to Duke University, Durham, NC where they were kept in individual compartments of a 300-gallon recirculating sea system. In binary choice experiments, a photograph of a mature female crab with red claws was presented along with the same photograph in which the red coloration had been changed to black or to white. By observing and scoring courtship behavior, we found that 15 out of 17 males preferred females with red claws to females with black claws (p < 0.002; one-tailed Exact Binomial Test) and 9 out of 11 males preferred red claws to white claws (p < 0.05; one-tailed Exact Binomial Test). These results are evidence for color vision in blue crabs and also imply that a long wavelength photopigment may be present. They also show that visual cues are used in mate attraction and preference, and that courtship behavior can be stimulated in the absence of pheromones. Visual signals may play a larger role in mate attraction and courtship than previously considered. Thus, water quality should be considered in conservation efforts because increasing water turbidity in mating areas of C. sapidus may limit signal visibility.