Evidence for colony-specific differences in chemical mimicry in the parasitic mite Varroa destructor

In social insects, the integrity of a colony is maintained by recognising and removing aliens. Nest-mates use chemical cues on the cuticle of the individual they encounter to determine whether or not it is part of the colony. Parasites have evolved to take advantage of this recognition system by mimicking these chemical cues to gain entry to the colony and therefore avoid being attacked by the host during their stay. Some of these parasites imitate the odour of a particular sub-group of colony members, such as pupae, which makes it more likely that they are accepted into the colony, whereas others mimic the adult colony odour. The ectoparasitic mite Varroa destructor uses chemical mimicry to access and remain undetected inside colonies of its honey bee host, Apis mellifera. It remains, however, to be tested whether the chemical profile of V. destructor mirrors colony-specific cues of the host’s chemistry that allows con-specific nest-mate discrimination to occur in honey bees. Here we show that colony-specific differences in the chemical profile of four A. mellifera colonies were based on differences in the n-alkane:alkene ratio. These colony-specific differences in chemical profile were mirrored by V. destructor mites collected from the same four colonies, even though overall chemical mimicry was imperfect