Communication ecology of webbing clothes moth: 2. Identification of semiochemicals mediating attraction of adults to larval habitat.

Our objective was to identify the semiochemicals that mediate attraction of the webbing clothes moth (WCM), Tineola bisselliella (Lepidoptera: Tineidae), to suitable larval habitat. Coupled gas chromatographic-electroantennographic detection (GC-EAD) analyses of Porapak Q-captured bioactive volatiles from horseshoe crab, and dried but untanned vertebrate pelts revealed numerous EAD-active volatiles. These volatiles were identified by comparative GC-mass spectrometry and GC-EAD analyses of natural and synthetic compounds. A blend of 28 synthetic candidate semiochemicals attracted both male and female WCM. Experiments deleting various components determined that saturated aldehydes--but not unsaturated aldehydes, saturated hydrocarbons, saturated alcohols, or ketones--were essential for blend attractiveness. A blend of nonanal, the single most attractive aldehyde, in combination with geranylacetone was more attractive to WCM than the 28-component blend or dried, untanned animal pelt. Selection of larval habitat resides more with male than female WCM, as indicated by stronger EAD responses from male than female antennae to habitat-derived semiochemicals, and more selective and early response to habitat cues by males than females. Exploitation of nonanal and geranylacetone as resource-derived semiochemicals by both adult WCM and its larval parasitoid, Apanteles carpatus, is an example of convergent semiochemical parsimony.