Identification of sex pheromone ofTetanolita mynesalis (Lepidoptera: Noctuidae), a prey species of bolas spider,Mastophora hutchinsoni

Abstract

The bolas spider,Mastophora hutchinsoni, attracts adult males of four species of nocturnally active Lepidoptera through aggressive chemical mimicry of those species' sex pheromones. Here we report the identification of the sex pheromone of one prey species, the smoky tetanolita (Tetanolita mynesalis). In sex pheromone gland extracts, only two peaks stimulated an electrophysiological response as measured by a coupled gas chromatography-electroantennographic detection analysis. These two peaks had retention times identical to (3Z,6Z,9Z)-heneicosatriene (3Z,6Z,9Z-21:H) and (3Z,9Z)-cis-6,7-epoxy-heneicosadiene (3Z,9Z-cis-6,7-epoxy-21:H), respectively, and mass spectra identical to these two compounds. It was determined that 0.23±0.16 and 0.56±0.26 ng of 3Z,6Z,9Z-21:H and 3Z,9Z-cis-6,7-epoxy-21:H, respectively, were present in pheromone gland extracts from individual females. A 1:1 blend of 3Z,6Z,9Z-21:H and 3Z,9Z-6S,7R-epoxy-21:H was an effective attractant for adult males from feral populations. Blend ratios of these two components from 2:1 to 1:2 were equally effective as attractants. Greater deviation from the optimal blends resulted in diminished trap catches. The enantiomer 3Z,9Z-6R,7S-epoxy-21:H not only was not effective in attracting males, its presence in the effective blend shut down trap catches. These results indicate that the pheromone blend consists of 3Z,6Z,9Z-21:H and 3Z,9Z-6S,7R-epoxy-21:H. This is the first report of a hydrocarbon/epoxide pheromone for a prey species of this bolas spider. Sex attractants or pheromones for the other three prey species are composed of aldehydes or acetates.