Figure 1.

Olfactory system of the female Aedes aegypti mosquito. (A) The A. aegypti head (dorsal view) possesses three olfactory appendages: the antennae, the maxillary palps (here colored yellow using Adobe Photoshop), and the proboscis. (B) Basiconic sensilla (white arrow) are the only chemosensory organs on the fourth segment of the maxillary palps (ventro-lateral view). (C) A basiconic sensillum is a club-shaped sensory organ. Pores (see insert) allowing odorants to penetrate the sensillum are densely distributed over the surface of the hair. (D) Diagram outlining the conceptual neuronal content of a basiconic sensillum. Three chemosensory neurons are enclosed within the sensillum. The CO₂ or “A” neuron expresses AaGr1 and AaGr3. The “B” neuron is presumed to express AaOr49-Orco (unknown ligand). The AaOR8-Orco complex confers octenol sensitivity to the “C” neuron (labeled in blue).