Moth's mating behaviour can help build better drones

Imitating moth mating behaviour can help researchers develop airborne robots or drones that ply the sky searching for signature odours from pollutants.
New research using computer simulations shows that mating behaviour of the insect has implications for airborne robots (drones) that ply the sky searching for signature odours.
Male moths locate females by navigating along the latter's pheromone (odour) plume, often flying hundreds of meters to do so.
Two strategies are involved to accomplish this: males must find the outer envelope of the pheromone plume, and then head upwind.
The entomologists modelled plumes' dispersal and insects' flight strategies. Their model was based in part on the observed behaviour of the gypsy moth in forests and in experiments in wind tunnels.

The use of computer simulations allowed testing of many conditions that could not be observed directly in the field.

The simulations suggest that optimal strategies for robotic vehicles - airborne or ground-based - programmed to contact an odour plume need not involve the detection of wind flow in setting a foraging path.
"Our simulations show that random walks - heading randomly with respect to wind and changing direction periodically - create the most efficient paths for the initial discovery of the plume and consequently the likelihood of the moth locating its source," said Ring Carde, professor at the University of California, Riverside, whose lab led the study.

"Such strategies are most apt to result in contact with plumes. Our simulations show that paths aimed downwind are least successful," said Carde.
Carde explained that in the model once the odour plume is encountered, the virtual moth navigates a course upwind to the odour's source.
"This process is well understood in flying insects such as moths, flies and mosquitoes," he said.
"But first the plume must be found and the best rules for an efficient searching strategy - find it quickly with a minimal energy expenditure - had not been established," said Carde.
One application of the work may be in using airborne drones to find sources of odours from pollutants. Such drones could mimic natural orientation paths of insects searching for odours.

The study was published in the journal Integrative and Comparative Biology.