A neuronal mechanism controlling the choice between feeding and sexual behaviors in Drosophila

Animals must express the appropriate behavior that meets their most pressing physiological needs and their environmental context. However, it is currently unclear how alternative behavioral options are evaluated and appropriate actions are prioritized. Here, we describe how fruit flies choose between feeding and courtship; two behaviors necessary for survival and reproduction. We show that sex-and food-deprived male flies prioritize feeding over courtship initiation, and manipulation of food quality or the animal's internal state finetunes this decision. We identify the tyramine signaling pathway as an essential mediator of this decision. Tyramine biosynthesis is regulated by the fly's nutritional state and acts as a satiety signal, favoring courtship over feeding. Tyramine inhibits a subset of feeding-promoting tyramine receptor (TyrR)-expressing neurons and activates P1 neurons, a known command center for courtship. Conversely, the perception of a nutritious food source activates TyrR neurons and inhibits P1 neurons. Therefore, TyrR and P1 neurons are oppositely modulated by starvation, via tyramine levels, and food availability. We propose that antagonistic co -regulation of neurons controlling alternative actions is key to prioritizing competing drives in a context-dependent manner.

Automated summary

This study describes how fruit flies make decisions between feeding and courtship behaviors, with nutritional status playing a key role in prioritizing these actions. The tyramine signaling pathway is identified as essential for mediating this decision-making process, with tyramine levels modulating the activity of neurons controlling food-seeking and courtship behaviors.