Integral part of a neural sensory system in the antenna that provides the neural basis for the response to environmental changes in humidity (hygrosensation) (PubMed:27161501, PubMed:27656904). Together with Ir25a and Ir93a, mediates the response of the hygrosensory sacculus neurons to changes in relative humidity and is required for dry detection behavior (PubMed:27161501, PubMed:27656904). In the antenna, detected in sacculus neurons which innervate the first and second chambers (at protein level). Response of sacculus neurons to changes in humidity is abolished and consequently larvae fail to move towards their preferred humidity. Belongs to the glutamate-gated ion channel (TC 1.A.10.1) family.