In the honeybee, Sensilla placodea, Sensilla trichoidea and Sensilla basiconica have been classified as olfactory sensilla
One striking sex-specific difference is the absence of S. basiconica on drone antennae
Honeybee workers possess a specific olfactory subsystem comprising S. basiconica, parts of the T3 cluster of glomeruli and a significant proportion of mALT PNs. Drones completely lack this olfactory subsystem (Fig. 7) and, additionally, have far fewer S. trichoidea, all features that might favor a more elaborated queen-pheromone-processing system and the associated higher numbers of S. placodea present in drones (Brockmann et al. 2006; Kaissling and Renner 1968; Sandoz 2006). At the behavioral level, drones, therefore, are likely to have more limited odor discrimination and recognition abilities compared with females. This limitation is likely to be associated with social (colony) odors and/or floral odors. The adaptation in drones for improved queen-pheromone detection including high numbers of S. placodea and pheromone-processing macroglomeruli is likely to increase mating probabilities. Honeybee workers, in contrast, are exposed to high selective pressure to identify and locate correctly a wide variety of odorants, including floral odorant mixtures, a large variety of pheromones and colony (social) cues. The different types of sensilla and the associated olfactory subsystems of glomeruli and output tracts in the AL appear to be well adapted for these tasks.