Meeting Abstract
Hair bundle mechanoreceptors located on the surface of anemone tentacles are employed to detect swimming movements of prey. Proper functioning of the hair bundles is inhibited in the presence of streptomycin. We here find that the anemone Nematostella vectensis preferentially discharges spirocysts, an adhesive cnida, onto the second antennae of brine shrimp nauplii that swim into contact with tentacles. Based on the relative size of ‘patches’ of discharged spirocyst tubules on the surface of the Artemia, the preference for discharging spirocysts onto second antennae, the primary swimming appendages of the nauplii, is by a factor of nearly 3 as compared to the telson, the nauplius region that ranks second in area of discharged spirocysts. In the presence of streptomycin, preferential discharge of spirocysts is abolished for the second antenna decreasing to a factor of only 1.08 as compared to the telson. Nevertheless, overall levels of spirocyst discharge are comparable in the presence and absence of streptomycin. Thus, hair bundle mechanoreceptors on tentacles likely participate in targeting discharge of spirocysts onto secondary antennae of nauplii. Streptomycin does not significantly affect swimming of brine shrimp nauplii. In the presence of streptomycin, anemones are less effective predators than they are in the absence of streptomycin. Evidently, hair bundles on tentacles target discharge of spirocysts to the second antennae of nauplii where the spirocyst tubules function to tether the shrimp to the tentacle and to entangle the second antennae such that swimming performance in prey organisms is greatly reduced.
