CUTICLE ALKANES OF HONEYBEE LARVAE MEDIATE ARRESTMENT OF BEE PARASITEVARROA-JACOBSONI

The ectoparasitic mite Varroa jacobsoni invades worker brood cells of the honeybee Apis mellifera during the last 20 hr before the cells are sealed with a wax cap. Cuticle extracts of 8-day-old worker honeybee larvae occupying such brood cells have an arrestment effect on the mit e. The mites run for prolonged periods on the extract, systematically returning onto the stimulus after touching the borders of the treated area. Mites increase walking speed and path straightness in response t o increasing doses of a nonpolar fraction of the cuticle extract. Satu rated straight-chain odd-numbered C-19-C-29 hydrocarbons were identifi ed by thin-layer argentation chromatography and gas chromatography-mas s spectrometry as the most active constituents, with branched alkanes also contributing to the arrestment effect of this active fraction. An alysis of the behavior responses to synthetic n-alkanes indicate that the response is probably based on a synergism between the different al kane components of the fraction rather than to an individual compound.