Studies on contact sex pheromones of the caridean shrimp Paldemonetes pugio: I. Cuticular hydrocarbons associated with mate recognition

In the grass shrimp Palaemonetes pugio, evidence suggests that males respond to an insoluble substance (i.e., contact sex pheromone) in or on the exoskeleton of the postmolt parturial female. Cuticular hydrocarbons, glycoproteins, or other compounds present on the surface of the female might serve as recognition signals. Cuticular hydrocarbons are known to function as contact sex pheromones in many insect species. The purpose of this study was to test the hypothesis that the exoskeleton of postmolt parturial females contains cuticular compounds that might function as contact sex pheromones. Gas chromatography-mass spectrometry (GC-MS) analyses of chloroform-methanol extracts of the cuticle of postmolt parturial (sexually receptive) females (PPFs), postmolt nonparturial females (NPFs), postmolt males (PMMs), and intermolt females (IMFs) showed at least 55 compounds, 3 of which were unique to postmolt parturial females. Extracts of PPFs, NPFs, PMMs, and IMFs were characterized by 49, 50, 34, and 19 compounds, respectively, of which 22 could be identified. Twelve cuticular hydrocarbons and five fatty acids were found in the cuticular extractions of P. pugio. Multivariate analysis of GC-MS profiles demonstrated that the cuticular composition of postmolt parturial females differed significantly from that of nonparturial females, males, and intermolt females. A bioassay to test male response to cuticular extracts gave inconclusive results. Although GC-MS enabled identification and partial quantification of some cuticular compounds, it is still undetermined which, if any, compounds function in mate recognition in P. pugio.