Professor University of Washington Seattle, Washington
Mosquitoes are important vectors of disease and require sources of carbohydrates for reproduction and survival. Unlike host-related behaviors of mosquitoes, comparatively less is understood about the mechanisms involved in nectar-feeding decisions, or how this sensory information is processed in the mosquito brain. Here we show that Aedes spp. mosquitoes, including Aedes aegypti, are important visitors of various floral nectar sources, including the Platanthera obtusata orchid. The associations between the mosquito and sources of nectar are mediated by a combination of the plant’s scent, operating as far-field cue, and the flower’s visual display that operates as a near-field cue. The nectar scents are enriched in attractive terpene and aliphatic compounds that elicit strong antennal (olfactory) responses. Recording and imaging the neuronal activity in the mosquito’s primary olfactory center, the antennal lobe (AL), revealed that the aliphatic and terpene compounds each activate distinct regions of the antennal lobe. The combination of compounds in these complex scents elicits distinct patterns of activity in the brain, allowing mosquitoes to discriminate between different scents. Moreover, we found that attraction to the flower’s visual display is gated by the presence of the scent – without the scent, the attraction to the visual display does not occur. Together these results demonstrate the importance of mosquitoes beyond operating as disease vectors and open the door towards understanding the sensory bases of mosquito nectar-seeking behaviors.
