Molecular control limiting sensitivity of sweet taste neurons in Drosophila

Significance When making feeding decisions for themselves or their progenies, animals must accurately decode both the identity and the quantity of relevant chemicals in potential food options. While much is known about how animals determine the identity of these chemicals, little is known about how they determine whether these chemicals are of relevant quantity. Here, we discover a molecule that limits the sensitivity of Drosophila taste neurons: its absence causes flies to exhibit abnormally high interest for very low levels of sucrose and acetic acid—2 nutritive stimuli that can activate Drosophila sweet neurons—that normal flies are less interested about. Our work shows that sensitivity for sweet neurons is actively limited and identifies a key regulator responsible for such control.