P2.3 Thursday, Jan. 5 Why have long antennae? Exploring the function of antennal contact in snapping shrimp VICKERY, R.E.; HOLLOWELL, K; HUGHES, M*; College of Charleston, SC email@example.com
Many organisms use antennae to gather information from the environment. Crustaceans uniquely have 2 sets of antennular organs, allowing for segregation of function: short antennules, used to perceive soluble chemical signals, and often much longer second antennae, primarily used for perception of contact chemical and/or tactile signals. While the roles of soluble chemical signals are known in many species, the role of direct antennal contact is poorly understood. Our objective was to determine the degree to which antennal contact behavior differs between social contexts, and between species with different antennal morphology. We staged competitive and pairing interactions in two species of socially monogamous, burrow-dwelling snapping shrimp, Alpheus angulosus and A. heterochaelis. A. heterochaelis performed more antennal contact overall than A. angulosus, and A. heterochaelis did not reduce antennal contact behavior in highly aggressive competitive interactions. These results suggest that antennal contact provides information not readily assessed by other means in A. heterochaelis, given the proportionally longer antennae in this species and the high risk of injury associated with antennal contact. Only A. angulosus females modified their antennal contact behavior according to context, performing more antennal contact in pairing than in competitions. In both species, pairing involves more antenna-to-antenna contact when the female has prior burrow residency, suggesting that antennal contact may play a role in female assessment of potential mates. Overall, we found differences in antennal behavior according to sex, species and context; this hitherto undocumented diversity in antennal behavior underscores the importance of considering direct antennal contact in studies of crustacean behavior and ecology.