Ground-nesting wasps are incredibly good at navigating the world, particularly when it comes to re-locating their nests. By tracking the intricate flight patterns and visual focus of these insects, scientists have simulated what a wasp sees as it makes its journey back home. Every time a ground-nesting wasp leaves home, it performs a rather predictable ritual. As it heads out for the day, it turns back to take a look. As it flies higher and further away from home in a series of ever-increasing arcs, it keeps its focus on the nest. These "learning flights", as they're called, allow the wasp to orient itself, and it makes a nearly identical journey back home, as if it were reverse engineering the trip.
A ground-nesting wasp (Cerceris arenaria) approaching her nest. Credit: Waltraud Pix.
To learn more about this process, and what wasps are actually seeing, a team of Australian researchers recorded the wasps' head orientation — that is the direction of the gaze — with high-speed cameras. They also moved a panoramic imager along the flight paths, and built 3D models of the wasps' environment to render views inside these models. This allowed them to reconstruct the visual field of the wasp, and of their home in particular.
Lead scientist Jochen Zeil of the Australian National University in Canberra said it took his team over 10 years to come up with this technique. "I was especially surprised by how long it took us to find the right way of looking at what the wasps were doing," he said in a statement.
The views collected by the researchers allowed them to test specific predictions about what the wasps were actually doing during the learning phase of their flights. To test these predictions, they simulated the homing flights of wasps in virtual reality. This showed that homing wasps perform predictable flight manoeuvres when they encounter familiar views. When a wasp encounters something it recognises, like a familiar tree, it will move either left or right depending on the next direction associated with that view. Wasps also use ground features, like rocks and fallen sticks, to make their way home.
Not only is this research helping scientists understand wasps a bit better, it could also be used to create sophisticated flying robots. "It will be interesting to implement the learning and homing rules we found into flying robots to test the validity and limits of our findings," said Zeil. "We want to understand what trick the insects are using to acquire the competence of homing."