Meeting Abstract
With over 3500 species, mosquitoes have evolved a wide range of host preferences, feeding on vertebrates, invertebrates, plant fluids and even ant regurgitation. Mosquitoes can use olfactory information from feeding experiences to learn positive or negative associations with certain hosts, but not all odors can be learned by each species. To understand the neural basis of differential learning across species with various host preferences, we used an integrative approach of combining behavioral assays with neuroanatomical studies to understand the neural underpinnings of these behaviors. To test the hypothesis that mosquitoes only learn the most salient odors associated with their preferred host, we trained mosquitoes from four species that prefer either human hosts, bird hosts, or purely nectar feeding in a classical conditioning paradigm. Aedes aegypti and Anopheles stephensi (prefer humans) learned vertebrate host odors, but not flower odor; Toxorhynchites amboinensis (nectar feeder) only learned a flower odor; and Culex quinquefasciatus did not exhibit learning behavior in this study. We next examined patterns of dopaminergic innervation in central brain pathways mediating olfactory learning such as the antennal lobes and mushroom bodies. Staining patterns suggest a relationship between differential abilities of mosquitoes to learn salient host odors and differential patterns of dopaminergic neuromodulation in olfactory learning circuits. These results contribute to our understanding of mosquito learning, which can modify vector-host transmission of diseases and more broadly to our understanding of dopaminergic modulation of olfactory learning circuitry in insects.
