Cellular and Molecular Basis of Odorant Reception in the Biting Midge Forcipomyia taiwana

Le résumé fourni par la source

Biting midges are medically significant pests whose bites trigger dermatitis and systemic allergic responses while transmitting diverse pathogens, thereby posing a severe threat to human health. How these and other blood-feeding insects parse complex odor environments to locate hosts while avoiding unfavorable cues is a fundamental question in sensory biology. However, the olfactory mechanisms underlying odorant detection in midges remain poorly understood. Here, we elucidate the neural and molecular mechanisms underlying odor-guided behavior in Forcipomyia taiwana, the predominant biting midge in China and Southeast Asia, using an integrated, multi-scale approach. The antennae contain diverse olfactory sensilla and a broad chemoreceptor repertoire that respond to host- and plant-derived volatiles. In contrast, spherical sensilla within the maxillary palp form a dual-channel olfactory pathway that segregates two ecologically salient classes of chemical information: one sensory neuron is strongly activated by host-associated CO2 and the other is preferentially tuned to plant-derived terpenoids. Tissue-resolved transcriptomics, receptor localization, and heterologous functional analysis identify the palp-enriched receptor FtaiOr1 as a strong molecular determinant of this terpenoid-sensitive pathway while FtaiOr27 and FtaiOr60 localize to the antennae and detect additional odor classes. These peripheral sensory responses correspond to opposing behavioral outcomes: terpenoids, including camphor, eucalyptol, and (+)-fenchone, strongly repel F. taiwana, whereas human-associated volatiles such as butanal and butanoic acid promote attraction. Together, these findings link receptor identity, neuronal coding, and behavior in an understudied hematophagous insect, revealing a mechanistic framework for understanding odor-guided behavior in biting midges and suggests broader principles by which blood-feeding Diptera partition ecologically opposing olfactory information.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.