Meeting Abstract

95.5  Wednesday, Jan. 7  Dynamics of Shrimp Goby Mutualism in the Caribbean LYONS, P.J.; Stony Brook Univ. plyons@life.bio.sunysb.edu

In the mutualism between burrowing alpheid shrimp and gobies, the goby gains shelter and the shrimp benefits from the alarm against predators generated by flutters of the gobys caudal fin. In the Caribbean, the shrimp, Alpheus floridanus, associates with three gobies; Nes longus, is an obligate mutualist, while two others, Ctenogobius saepepallens and Bathygobius curacao, are facultative mutualists. I studied dynamics of the N. longus and C. saepepallens association with A. floridanus in the Bahamas. N. longus density was positively correlated with A. floridanus density but C. saepepallens density showed no trend. N. longus individuals are always associated with a single burrow often positioned to best relay warning to their shrimp partner (proximal to the entrance and with the caudal tail pointing toward the entrance); C. saepepallens are nomadic and rarely positioned as such. N. longus, the obligate mutualist seek shrimp partners, while C. saepepallens only seek shelter. A. floridanus prefer entrances guarded by N. longus rather than the facultative mutualist C. saepepallens. N. longus individuals compete for shrimp partners, the outcome which is determined by the size of the competitors. Our results demonstrate the dimensions of the facultative and obligate states of C. saepepallens and N. longus, respectively. N. longus and A. floridanus are seemingly well co-evolved. Reportedly, the third goby B. curacao often remain associated with one shrimp (as N. longus does) but do not provide a warning signal (as C. saepepallens doesnt). We speculate that C. saepepallens represents a first step toward obligate mutualism, B. curacao a second step, and N. longus the final step.