Meeting Abstract

30.5  Monday, Jan. 4  The Setal Patch of a Macrobrachium Shrimp: Grooming function, a Sexual dimorphism, or our Black box? VAN MAURIK, L.N.**; WORTHAM, J.L.; MCRAE, M.G.; University of Tampa, FL; University of Tampa, FL; University of Tampa, FL Lvanmaurik@ut.edu

Many crustaceans expend a great amount of time grooming and decreasing fouling. Grooming behaviors include cleaning of structures used in chemoreception, respiration (gills), reproduction, feeding, and general cleaning of the body. The Hawaiian river shrimp, Macrobrachium grandimanus, migrates between freshwater and marine habitats and is exposed to environmental pressures that may increase the need for grooming. This species has a dense “setal patch” found on the larger cheliped that may be useful in grooming behaviors. There have been no behavioral or functional morphology studies on this species. The frequency and duration of all grooming behaviors for M. grandimanus were documented during thirty minute time periods (N=62) or 24-hr continual observation periods (N=32). Morphometric analyses were also conducted to determine if differences existed between sexes and size classes with respect to the size and structure of the chelipeds. Microscopic imaging was used to elucidate possible functions of the setal patch. M. grandimanus had a large time budget for grooming when compared to other crustaceans. Males and females differed in their grooming behaviors. The body regions groomed most frequently were the antennae and antennules while their sub-carapace region was groomed the most in terms of time; the “setal patch” was rarely groomed and never involved as a grooming appendage. The two main grooming appendages used were the third maxilliped and the first pereiopod, not the “setal patch” cheliped. Based on morphometric measurements, four different chela morphotypes were classified. The “setal patch” does not appear to have a function related to grooming.