SPECIES-DETERMINED AND CASTE-DETERMINED MANDIBULAR GLAND SIGNALS IN HONEYBEES (APIS)

Queens and workers of five honeybee species (Apis mellifera, A. cerana , A. dorsata, A. florea, and A. andreniformis) were analyzed for their mandibular gland components. In A. mellifera, the queen mandibular ph eromone consists of 9-hydroxy- and 9-keto-2(E)-decenoic acids (8-HDA a nd ODA), methyl p-hydroxybenzoate (HOB), and 4-hydroxy-3-methoxyphenyl ethanol (HVA), and is responsible for retinue attraction, among other functions. In retinue bioassays with workers of A. cerana (whose queen s lack HVA), ODA, 9-HDA, and HOB were sufficient to elicit maximal ret inue behavior. This suggests that the known queen mandibular pheromone components detected in mandibular glands of A. cerana queens constitu te the functional queen mandibular pheromone in this species. Both cas tes of A. mellifera produce 10- and 8-carbon acids that are functional ized at the last position in the chain, and these are the predominant compounds found in worker mandibular glands. Workers of the other spec ies also had these compounds, along with 9-HDA and ODA that are normal ly not present in A. mellifera worker glands. Queens and workers of ea ch species had a unique combination of mandibular compounds. The aroma tic compounds were characteristic of queens from the cavity-nesting sp ecies, A. mellifera (HOB and HVA) and A. cerana (HOB). These two speci es also had more pronounced differences in the mandibular blends of qu eens and workers than the open-nesting species, A. dorsata, A. florea, and A. andreniformis. Our results indicate that the more derived cavi ty-nesting species of Apis have evolved greater caste-specific differe nces between queens and workers and a higher number of queen pheromone components, compared to the open-nesting species.