1.A.4.3.2
The Nanchung (Nan) hearing ion channel; mediates hypo-osmotically activated Ca²⁺ influx in chordotonal neurons of insects (Kim et al., 2003). Nanchung is the "dry" humidity receptor, one of two hygrosensation receptors. These two transient receptor potential channels are needed for sensing humidity.  The other is Water witch (Wtrw), involved in detecting moist air. Neurons associated with specialized sensory hairs in the third segment of the antenna express these channels, and neurons expressing Wtrw and Nan project to central nervous system regions associated with mechanosensation. Construction of the hygrosensing system with opposing receptors may allow an organism to very sensitively detect changes in environmental humidity (Liu et al. 2007). Two commercial insecticides, pymetrozine and pyrifluquinazon, target the heteromeric TRPV ion channel complex which is specifically expressed in the chordotonal organ neurons in Drosophila species and may play roles in male-specific behavior (Mao et al. 2018).