Variations in chemical mimicry by the ectoparasitic mite Varroa jacobsoni according to the developmental stage of the host honeybee Apis mellifera

The ectoparasitic mite Varroa jacobsoni poses a major threat to the surviva l of European honey-bee populations. Development of effective control metho ds is therefore much needed. Study of interspecific chemical communication between the parasite and host is a particularly promising avenue of researc h. Previous study has shown that the cuticular hydrocarbons of the parasite mite Varroa jacobsoni are qualitatively identical to those of its honey-be e host Apis mellifera (Nation J.L., Sanford M.T., Milne K., 1992. Cuticular hydrocarbons from Varroa jacobsoni. Experimental and Applied Acarology 16, 331-344). The purpose of the present study was to compare the cuticular hy drocarbon patterns of the two species at different stages of bee developmen t. Cuticular components were identified by gas chromatography/mass spectrom etry. The proportion of each component was calculated at three stages of be e development (larvae, pupa, emerging bee). The degree of chemical mimicry between the parasite and host was evaluated by multivariate analyses using the resulting proportions for each category of individuals. There were four main findings. The first was that the proportions of some components are d ifferent at the larval, pupal and image stage of bee development. Second, V arroa profiles vary depending on the developmental stage of the host. Third , the cuticular profile of adult mites is more similar to that of the stage of the host than that of later and/or earlier stages except for parasites collected from emerging adult bees. Fourth, the degree of mimicry by Varroa is greater during larval and pupal stages than during the emerging adult b ee stages. The role of chemical mimicry - although it is not perfect - in e nabling parasites to infest bee colonies by the parasite is discussed. (C) 2001 Elsevier Science Ltd. All rights reserved.