Bats imitate hornet sounds to force predators to buzz off
IN THE evolutionary arms race between predator and prey, animals might become poisonous, develop camouflage or evolve armour to survive.
But some take a shortcut, imitating the defences of other animals to trick their foes. Scientists in Italy have discovered this tactic in bats, finding a European species that buzzes like a hornet to avoid being eaten by owls.
The greater mouse-eared bat may emit the noise before or after capture by an owl, to make the predator think it is holding a stinging insect.
Researchers believe this is the first case, recorded in mammals, of acoustic Batesian mimicry – when a harmless species imitates a more dangerous one in order to protect itself.
Dr Danilo Russo from the University of Naples Federico II in Portici, who cowrote the study, said: “In Batesian mimicry, a non-armed species imitates an armed one to deter predators.
“Imagine a bat that has been seized but not killed by the predator. Buzzing might deceive the predator for a fraction of a second – enough to fly away.”
The researchers made the discovery while conducting field research in which they frequently caught the bats in mist-netting operations. Dr Russo said: “When we handled the bats to take them out of the net or process them, they invariably buzzed like wasps.”
The team played recordings of the buzzing sounds to owls, finding the birds reacted to both insect and bat buzzes by moving away from the source, while the sound of potential prey made them move closer.
According to the researchers, while stinging insects probably do sting owls, there is not enough data to prove this is why the birds avoid the buzzing sounds. However, there is evidence that birds avoid noxious insects if they can, showing a precedent for owls to be cautious of animals that buzz.
According to the Bat Conservation Trust, the greater mouse-eared bat was officially declared extinct in the UK in 1990, but a solitary individual has been hibernating in southern England since 2002, and they are still found in Europe.
Another example of Batesian mimicry include the poisonous coral snake, which is venomous, as its name would suggest, and the king snake, which looks very similar but is harmless.
The monarch butterfly is toxic to would-be predators and birds give it a wide berth. The viceroy butterfly has adapted overtime to look like the monarch, borrowing its reputation.
The study’s findings were published in the journal