The pure path-integration system of homing dung beetles
Several groups of African desert dung beetles face a challenging navigation task: They live in a semi-permanent burrow as central place foragers. These homing dung beetles repeatedly walk away from their burrow in search of food and then return with their forage, usually in a straight line. To solve this difficult task, they perform path integration, a navigational strategy that involves calculating a constantly updated "home vector" that informs the animal about the exact distance and direction of its burrow at any time. For this strategy to work, the beetle relies on a sky compass to measure direction and a "step-counter" to measure distance. Like ball-rolling dung beetles, but unlike any other path-integrating insect ever studied, they completely ignore landmarks. This pure path integration behaviour, combined with the beetles' robust behaviour and large size, makes them a great model to study the neuronal substrate of step-counting and path integration.
We have also recently discovered that some of these beetles walk in completely different way to any other insect ever observed, a unique "galloping" gait. Has this unique gait evolved to provide a more accurate distance estimate when the beetles walk on slippery desert sand dunes?
The ultimate aim of this project is to develop dung beetles as a model to investigate the neuronal substrate of path integration, particularly the integration of direction (compass) and distance (odometer) information in the brain.