Zoological Studies

Sensitivity of Crayfish Procambarus clarkii Antennules to Hydrodynamic Stimuli is Reduced during Diazinon Exposure

Harold M. Monteclaro, Kazuhiko Anraku, Seiichi Uno, Jiro Koyama, Tatsuro Matsuoka, and Hong-Young Yan (2011) In this study, the susceptibility of crustacean antennular mechanosensitivity to a pesticide was examined. We investigated the sensitivity of crayfish Procambarus clarkii Girard antennules to sinusoidal stimuli during a short-term exposure to different concentrations of diazinon. Electrophysiological recordings from the antennules showed that neural activities in the crayfish antennules were still present 2 h after exposure to diazinon, although at decreased rates. In addition, responses to hydrodynamic stimuli indicated that the mechanosensitivity of crayfish antennules was reduced after exposure to concentrations of as low as 0.5 mg/L. The reduction in mechanosensitivity was larger and more rapid in the lateral flagellum than the medial flagellum. Observations from dye experiments showed that ambient water was more readily absorbed at the lateral flagellum than the medial flagellum probably because of differences in the setal structures of the 2 flagella. We discuss the results in relation to the possible immediate sublethal effects of diazinon on the ability of animals to search for and detect chemical and hydrodynamic cues that are important in feeding, mating, and prey/predator detection. Such information is important considering the rapid degradation of diazinon in the natural environment.