• A ground-nesting wasp (Cerceris arenaria) approaching her nest. Image by Waltraud Pix (Supplied)Source: Supplied
Aussie researchers have found that wasps memorise their environment each morning to later find their way back to the nest.
Sandrine Ceurstemont

New Scientist
15 Feb 2016 - 1:25 PM  UPDATED 15 Feb 2016 - 5:06 PM

Step behind the eyes of a wasp. These reconstructions of how the insects see the world are revealing how they find their way home.

Wasps have low-resolution vision, so they rely on visual cues and a photographic memory for navigation. Every morning, they embark on information-gathering missions when they first leave their nests to help guide them home later, but what they learn about their environment has been a mystery.

To try and figure this out, Jochen Zeil of the Australian National University in Canberra and his team used high-speed cameras to track the head movements of ground-nesting wasps (Cerceris australis) during these flights.

The camera views allowed the team to monitor changes in a wasp’s gaze and recreate its flight path and what it sees. This enabled them to build virtual 3D models of their panoramic views. “We knew that the insects perfectly control the orientation of their heads,” says Zeil.

When wasps leave their nest, they turn to face the entrance rather than their destination. They then fly in a semicircle in front of it while watching the entrance and quickly looking from side to side, and gradually back away by moving along increasingly wide arcs (see video below).

This behaviour may help them to remember features on the ground, such as distinctive stones or fallen leaves, so they can find the direction of their nest when they return close to home. “We were surprised by how precise the choreography of learning flights was,” says Zeil.

On their way back, using views they have learned, the wasps can predict whether they need to head to the left or right to reach their nest.

Homing insects

Zeil suspects that the strategies they use could apply to other insects. “We rely on the ability of insects to find their way around, for example, for pollination or to produce honey, but we are just beginning to understand what makes them so competent,” he says.

Reconstructing a wasp’s-eye view of their natural environment is a major step forward, says Paul Graham of the University of Sussex, UK, who studies how ants use vision for navigation.

“What has eluded us is an understanding of how the learning flight relates to subsequent navigation,” he says. “Zeil and his team were able to evaluate the information available to the wasp at all points during the learning flight and the return journey.”

Next, the team hopes to record wasp flights and views over a much wider area around their nests, and monitor how their homing abilities develop during their lifetime.

Journal reference: Current Biology, DOI: 10.1016/j.cub.2015.12.052

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