Physiological and Behavioral Characterization of Larval Olfaction in the Malaria Vector Mosquito Anopheles coluzzii.

When viewed from both academic and vector-control perspectives, the chemosensory biology of larval-stage anopheline mosquitoes is both enigmatic and paradoxical. As is true for all mosquito species, anopheline larvae are free-swimming organisms that use complex sensory processes to both locate nutrients and avoid predators. Because of their obligatory and therefore restrictive aquatic habitats, mosquito larvae are the most easily sampled and targeted mosquito life stage and as such they have been the focus of the majority of vector control strategies used to date. Although this might reasonably have resulted in the accumulation of a robust body of knowledge of the natural and molecular biology of larval-stage chemosensory processes, there is, instead, a paucity of such information relative to adults. Here, we describe two relatively simple laboratory-based bioassays that allow for the characterization of larval chemosensory-driven behaviors as well as an electrophysiological approach to examine the responses of larval peripheral neurons to volatile odorant stimuli. Taken together, these approaches provide a road map for the study of the chemosensory biology and chemical ecology during this important stage in the life cycle of anophelines that transmit malaria.