ALIPHATIC-ALCOHOLS AND ALDEHYDES OF THE HONEY-BEE COCOON INDUCE ARRESTMENT BEHAVIOR IN VARROA-JACOBSONI (ACARI, MESOSTIGMATA), AN ECTOPARASITE OF APIS-MELLIFERA

The ectoparasitic mite Varroa jacobsoni reproduces in the capped brood of the honey bees Apis cerana and Apis mellifera, Observations on the reproductive behavior of the mite have shown a well-structured spatia l allocation of its activity using the bee or cell wall for different behaviors, The resulting advantages for the parasite of this subdivisi on of the concealed brood environment suggests an important role for c hemostimuli in these substrate. Extracts of the European honey bee coc oons induce a strong arrestment response in the mite, as indicated by prolonged periods of walking on the extracts applied on a semipermeabl e membrane and by systematically returning to the stimulus after encou ntering the treatment borders, Two thin-layer chromatography fractions of the cocoon extract eliciting arrestment were found to contain satu rated C-17 to C-22 primary aliphatic alcohols and C-19 to C-22 aldehyd es. We analyzed extracts of the cocoon and different larvae, pupae, an d adults of both worker and drone A, mellifera to determine the relati ve amounts of these chemostimuli in the different substrates employed by Varroa, Both aldehydes and alcohols were more abundant in the cocoo n than in the cuticle of adult or developing bees. Mixtures of the ali phatic alcohols and aldehydes at the proportions found in the cocoons acted synergistically on the arrestment response, but this activity di sappeared when mixed in equal amounts, When these oxygenated chemostim uli were mixed with C-19 to C-25 alkanes at the proportions found in t he cocoon extract, we observed a significantly lower threshold for the chemostimulant mixture, These results indicate how Varroa may use mix tures of rarer products to differentiate between substrates and host s tages during its developmental cycle within honey bee brood cells. (C) 1998 Wiley Liss, Inc.