Antennal sensilla pattern distribution and odor detection in Bombus pauloensis foragers (Hymenoptera: Apidae)

Insects rely on chemical information from the environment to survive. The reception of this information mainly occurs through the antennae, when the stimuli contact the sensory receptors located within specialized structures named sensilla. Some bee species present a different number of olfactory sensilla on both antennae and dissimilar responses, denoting olfactory lateralization evidenced by asymmetrical learning abilities. Here, we studied the antennae sensilla pattern and antennal odor detection in the bumblebee Bombus pauloensis, to evaluate olfactory lateralization. By scanning electron microscopy, we quantified and identified antennae sensilla types, and, by electroantennography, we recorded the responses to odors with different hedonic values. We found nine types of sensilla, being the trichodea the most prevalent type. Neither the number of sensilla nor the olfactory responses were different between the left and right antennae. Our findings suggest the absence of olfactory lateralization in B. pauloensis, providing new insights into the complexity of the bee olfactory system and shedding light on the biology of this commercially important bumblebee species, widely employed for crop pollination services.