Pheromonal basis of aggregation in European earwig,Forficula auricularia L. (Dermaptera: Forficulidae).

The aggregation behavior of the European earwigForficula auricularia was investigated. Bioassays of frass extracts, cuticular washings, and the defensive exudate have been conducted to locate the source of an aggregation pheromone, and aggregation behavior has been demonstrated with extracts of frass and the washings of male cuticular lipids. Chemical investigations revealed the presence of a unique pattern of typical normal, monomethyl-, and dimethylalkanes, along with a series of fatty acids and the well-known defensive quinones from these insects. It has been concluded from the bioassays of a number of authentic compounds and the lack of a chemically discernible difference between male and female extracts that the aggregation pheromone ofF. auricularia is quite probably a minor component of the male cuticular lipids.