Abstract:
The bee louse Braula spp. had until recently a distribution coincident with its host the honey bee. The adult fly usually
attaches to a worker honey bee and steals food from its mouth. However, not all worker bees carry Braula spp. and the mechanism
used by Braula spp. to select hosts is not well understood. Using choice remounting bioassays and chemical analyses,
we determined host selection and the cues used by B. coeca, a species associated with the African honey bee Apis mellifera
scutellata. Braula coeca successfully remounted bees from which they were initially removed and preferred their mandibular
gland pheromones (MDG) over those of bees not carrying them. The bee lice did not show any preference for the cuticular
hydrocarbons of both types of workers. Chemical analyses of the MDG extracts, revealed quantitative differences between the
two categories of workers, with workers carrying B. coeca having more of the queen substance (9-oxo-2(E)-decenoic acid)
and worker substance (10-hydroxy-2(E)-decenoic). Braula coeca showed a dose response to the queen substance, indicating
its ability to use host derived kairomones as cues that allowed it to benefit from trophallactic dominance by individuals that
have a higher probability of being fed by other workers.
