Description:
<jats:p><jats:bold>Abstract</jats:bold> The parasitic mite <jats:italic>Varroa destructor</jats:italic> Anderson & Trueman is a major pest of the honeybee <jats:italic>Apis mellifera</jats:italic> L. throughout the world. Chemical agents currently used for mite control leave contaminating residues and promote pesticide resistance. As an alternative means of control, it would be useful to identify natural substances enabling bees to detect <jats:italic>Varroa</jats:italic> inside brood cells. These substances could then be used to trigger mite hygienic behaviour by bees.</jats:p><jats:p>In this study several techniques were used to screen substances that might allow detection of infested brood cells by bees. Gas chromatography‐mass spectrometry analysis was performed on substances extracted in dichloromethane from the contents of brood cells. Solid phase microextraction and solid injection were performed on substances obtained from living and dead <jats:italic>Varroa,</jats:italic> respectively. Electroantennography was performed to assess the sensitivity of olfactory receptors in bee antennae to some of these substances.</jats:p><jats:p>Principal component analysis based on proportions of cuticular substances allowed discrimination between bees and other cell contents. Foundress <jats:italic>Varroa</jats:italic> exhibited the greatest dissimilarity to healthy pupae that were used as controls. Immature <jats:italic>Varroa</jats:italic> and faecal material were intermediate. High molecular weight compounds, mainly dimethylalkanes, were proportionally the most characteristic components of foundress <jats:italic>Varroa</jats:italic>. This finding suggests that these compounds would be the most apt to induce uncapping of cells infested by <jats:italic>Varroa</jats:italic>. Solid‐phase microextraction and solid injection demonstrated the presence of aliphatic acids, esters, and one alcohol, eicosenol, in <jats:italic>Varroa</jats:italic>. Electroantennographic recordings showed that mite‐resistant bees were more responsive to some acids and one ester. We speculate that these compounds may be involved in recognition of living <jats:italic>Varroa</jats:italic> by honeybees.</jats:p>