Insects are relatively small heterothermic animals, thus they are highly susceptible to changes in ambient temperature. However, a group of honey bees is able to maintain the brood nest temperature between 32°C and 36°C by either cooling or heating the nest. Nevertheless, how honey bees sense the ambient temperature is not known. We identified a honey bee Hymenoptera-specific transient receptor potential A (HsTRPA) channel (AmHsTRPA), which is activated by heat with an apparent threshold temperature of 34°C and insect antifeedants such as camphorin vitro. AmHsTRPAis expressed in the antennal flagellum, and ablation of the antennal flagella and injection of AmHsTRPA inhibitors impair warmth avoidance of honey bees. Gustatory responses of honey bees to sucrose are suppressed by noxious heat and insect antifeedants, but are relieved in the presence of AmHsTRPA inhibitors. These results suggest that AmHsTRPA may function as a thermal/chemical sensorin vivo. As shown previously, Hymenoptera has lost the ancient chemical sensor TRPA1; however, AmHsTRPA is able to complement the function ofDrosophila melanogasterTRPA1. These results demonstrate that HsTRPA, originally arisen by the duplication ofWater witch, has acquired thermal- and chemical-responsive properties, which has resulted in the loss of ancient TRPA1. Thus, this is an example of neofunctionalization of the duplicated ion channel gene followed by the loss of the functionally equivalent ancient gene.