What can fruit flies teach us about karate?

Abstract

Understanding the logic behind how a fruit fly's brain tells it to groom its body parts in a stereotyped order might help us understand other behaviours that also involve a series of actions.

Keywords: action selection; behavioral choice; competing motor programs; competitive queuing; grooming sequence; serial behavior.

Figure 1.. Competitive queuing produces sequential grooming behaviour.

Seeds et al. suggest that grooming behaviour in fruit flies uses a three stage algorithm to select which cleaning module to perform: sensory input (top), hierarchical suppression (middle), and a winner-take-all competition (bottom). The dust (yellow dots) activates each cleaning module. When the fly is completely covered with dust, all the modules receive sensory input and are activated in parallel. The ‘hierarchical suppression’ stage determines the degree of activation for each module (represented by the area of the coloured region in each circle) in order to implement the order of priority. The most active module is selected and the corresponding body part is cleaned, with all other cleaning modules being suppressed. As dust is removed from a body part, the sensory input to that module is reduced (represented by the blunt arrow). Eventually, this module is no longer the most active module and a new module is selected. Multiple iterations of this process produce the sequential grooming behaviour observed in fruit flies.