Meeting Abstract
26.1 Friday, Jan. 4 Identification and characterization of chemoreceptive sensilla on the antennal flagellum of Palaemonetes pugio CASKEY, Jodi L*; WATSON, Glen M; University of Louisiana at Lafayette; University of Louisiana at Lafayette shrimpgirl@louisiana.edu
Innervated structures (sensilla) on the external cuticle provide crustaceans with information about their external chemical environment. The antennules of crustaceans are primary structures for distance chemoreception and aid in reception of distance sex pheromones. The long flagella of the second antennae of some decapods are considered to be chemotactile with touch and taste receptors. The antennal flagella thus serve in contact chemoreception, responding to insoluble or low-solubility compounds. In Palaemonetes pugio setae are significantly more abundant on the antennal flagellum of males than of females. Sexual dimorphism in morphological structures is typically indicative of sexual differences in function. This difference in setation of the antennal flagellum suggests that males rely more heavily on chemoreception than do females. This is in accordance with previous work that suggests that females of this species employ a contact sex pheromone to attract mates. We hypothesize that the setae on the antennal flagella of P. pugio function as chemoreceptors and aid in the recognition of sexually receptive females. In order to describe the innervation and function of the antennal setae, a retrograde fluorescent dye, DiI, coupled with epifluorescent microscopy was used and allowed us to trace the neuronal tracts of the setae. Initial results show long axons that run longitudinally along each side of the antennal flagellum down the length of the flagellum. Large neuron bundles, 40 microns in dia., have been identified at the base of setal clusters (4-6 setae). Based on our preliminary findings we predict that these setae are bimodal setae and that further examination through Transmission Electron Microscopy and further fluorescent imaging will support our hypothesis.
