# A decision underlies phototaxis in an insect

## TL;DR

Flies adjust their light-seeking behavior based on their ability to fly, showing that even simple behaviors involve decision-making.

## Contribution

The study reveals that Drosophila phototaxis is flexible and influenced by the fly's internal state, specifically its ability to fly.

## Key findings

- Phototaxis in Drosophila reverses when flying ability is compromised.
- Dopamine and octopamine circuits differentially influence this behavioral flexibility.
- Behavioral decisions in flies integrate internal state with external stimuli.

## Abstract

Like a moth into the flame - Phototaxis is an iconic example for innate preferences. Such preferences likely reflect evolutionary adaptations to predictable situations and have traditionally been conceptualized as hard-wired stimulus-response links. Perhaps therefore, the century-old discovery of flexibility in Drosophila phototaxis has received little attention. Here we report that across several different behavioral tests, light/dark preference tested in walking is dependent on various aspects of flight. If we temporarily compromise flying ability, walking photopreference reverses concomitantly. Neuronal activity in circuits expressing dopamine and octopamine, respectively, plays a differential role in photopreference, suggesting a potential involvement of these biogenic amines in this case of behavioral flexibility. We conclude that flies monitor their ability to fly, and that flying ability exerts a fundamental effect on action selection in Drosophila. This work suggests that even behaviors which appear simple and hard-wired comprise a value-driven decision-making stage, negotiating the external situation with the animal’s internal state, before an action is selected.