MULTIPLICITY OF GLANDS AND SEMIOCHEMICALS INVOLVEDIN SEXUAL COMMUNICATION AND SEXUAL SELECTION OF THE STAPHYLINID BEETLE,ALEOCHARA CURTULA.

Klaus Peschke¹, Stephan Franke² and Wittko Francke^2
1Institut für Biologie (Zoologie), Hauptstr. 1, D-79104Freiburg, Germany.
²Institut für Organische Chemie, Martin-Luther-King-Platz6, D-20146 Hamburg, Germany.

In the rove beetle, A. curtula, we identified (Z)7-tricosene,a constituent of cuticular hydrocarbons, as the major compound of a femalesex pheromone acting at close range. This component is also produced bymales as a mimicking pheromone to avoid intrasexual aggression. The aggressivestrategy is costly in terms of the tergal gland secretion used as a chemicalweapon. This defensive secretion comprises substituted 1,4-benzoquinonesand aliphatic hydrocarbons and aldehydes. By using toluquinone as a calibrationsubstance for closed-looped-stripping-analysis (CLSA), we found that malesemit the secretion especially during combats. By tandem bioassay-mass fragmentographywe detected the pulsed emission of considerable amounts of the secretionduring fighting behaviour. The production of isopropyl (Z)9-hexadecenoate,which occurs only in males, was measured from surface extracts, sternalgland preparations and CLSA. Caged live males as well as synthetic isopropyl(Z)9-hexadodecenoate attract males and females of A.curtula in thefield. We consider the attraction of females as the adaptive function ofthe ester. The attraction of competing males is regarded as an exploitationof information, which is not adaptive for the emitter. The use of thisvariety of semiochemicals in different mating tactics of A. curtulaaffects intrasexual selection in males as well as female choice. Closelyrelated species, like the economically important A. bilineata, usethese pheromones differently.