Vector navigation in walking bumblebees

Path integration is a computational strategy that allows an animal to maintain an internal estimate of its po-sition relative to a point of origin. Many species use path integration to navigate back to specific locations, typically their homes, after lengthy and convoluted excursions. Hymenopteran insects are impressive path integrators, directly returning to their hives after hundreds of meters of outward travel. Recent neurobiolog-ical insights have established hypotheses for how path integration vectors could be encoded in the brains of bees, but clear ways to test these hypotheses in the laboratory are currently unavailable. Here, we report that the bumblebee, Bombus terrestris, uses path integration while walking over short distances in an indoor arena. They estimate accurate vector distances after displacement and orient by artificial celestial cues. Walking bumblebees also exhibited systematic search patterns when home vectors failed to lead them accu-rately back to the nest, closely resembling searches performed by other species under natural conditions. We thus provide a robust experimental system to test navigation behavior in the laboratory that reflects most as-pects of natural path integration. Importantly, we established this assay in an animal that is both readily avail-able and resilient to invasive manipulations, as we demonstrate with the retention of the homing behavior post-anesthesia and surgery. In the future, our behavioral assay can therefore be combined with current elec-trophysiological techniques, opening a path toward directly probing the neural basis of the sophisticated vector navigation abilities of bees.

Automated summary

The study found that bumblebees are capable of using path integration and artificial celestial cues to accurately estimate vector distances and orient themselves within short distances. They also exhibit systematic search patterns when they fail to return accurately to their nests.