Fruit flies bred to halt the spread of the destructive crop pest are more successful at mating once they’ve faced off with a miniature robot designed to look like a rival male.
A major fruit pest across the world, scientists have been attempting to control local populations of Mediterranean fruit fly (Ceratitis capita) by releasing large numbers of lab-reared sterile males into the wild.
The goal is for sterile males to mate with females but produce no offspring, helping to eradicate the pest in certain areas.
However, scientists have discovered that mass-rearing male flies in laboratories reduces their competitiveness when it comes to mating with wild females — thanks in part to rearing conditions, but also because of the sterilisation procedure.
This means the flies are less effective at foraging and show fewer mating behaviours, limiting their success as a biological pest control.
To see if they could help males have more luck with the ladies, researchers at the Sant’ Anna School of Advanced Studies in Pisa, Italy, investigated if flies’ natural competitive behaviour could be improved through learning and experience — in this case, through the use of tiny replicas.
In their study, scientist Donato Romano and his colleagues introduced flies into a plexiglas cage and gave them time to establish territories on discs of citrus leaves.
A 3D-printed, magnetic fly was then moved towards the discs, using a robotic system beneath the arena to direct it towards the males.
Males that showed aggressive reactions to the robot, such as striking it with their wings, rocking their heads or boxing it with their front legs, where then used in a mating experiment.
The researchers found these flies performed significantly longer courtship behaviours and were more successful in mating than males that hadn’t faced off with the replica fly.
Writing in the journal Biological Cybernetics, Romano said making lab-reared males more competitive could improve the success of sterile insect programmes, which have had high levels of success in reducing fruit crop damage.
“Learning and experience… can have a crucial role to increase quality and performance of mass-reared insects, changing paradigms for animal management,” he said.
“This study… paves the way to innovative biotechnological control methods based on robotics and bionics,” he added.
“Overall, our research shows that biomimetic robotics and ethorobotics may have a crucial role in future environmental and agricultural management approaches aimed at increasing sustainability.”
