Chemoreception in the antennule of the lobster,Homarus americanus

Abstract

Chemoreceptors in the lobster antennule respond electrophysiologically to a large range of pure chemical substances including amino acids, sugars, alcohols, amines and fatty acids, in several cases down to thresholds below 10−6 or 10−7 M. Test substances were introduced by pipette into a current of sea water flowing over the isolated antennule and responses were recorded by hook electrode from small nerve fibre bundles in the antennular nerve. In many nerve bundles the responses consisted of multiunit activity, no individual nerve spikes being identifiable, while in other bundles large spikes due to one or more single receptor neurones were present. There are striking differences in response spectrum between the single and multiunit responses, which with other evidence suggest the presence of two major classes of antennular chemoreceptor. The results support the idea that in the lobster and other Crustacea the antennules are the site of sensitive chemoreceptors mediating such distance chemoreception responses as seen in trapping behaviour.