Study: Bats, moths evolution 'arms race'

BRISTOL, England, Aug. 19 (UPI) -- Bats and moths, as predator and prey, are locked in an evolutionary "arms race" with survival as the goal, British researchers say.

Studies have found that in the ongoing escalation, some bats have learned to emit "stealth" clicks that moths can't hear as they search for prey, while some species of moth have learned to tell the difference between "locating" clicks and "striking" clicks and can react accordingly, the BBC reported Thursday.

Bats navigate and hunt by emitting a stream of ultrasound clicks and listening for the echoes in a natural form of radar, with the clicks coming faster and faster as the bats approach their prey.

Some moths, when hearing the clicks, are known to reply with their own high-intensity "jamming" clicks, or to fly erratically in circling evasive maneuvers, or even simply drop out of the sky.

Researchers say the battle between bats' strategies to hunt and the moths' strategies to avoid being eaten is a classic example of co-evolution.

"It often seems like predators and prey are going through a continuous cycle or 'arms race', where each is trying to outwit the other," Hannah ter Hofstede, a University of Bristol researcher, said.

"The predator is always trying to capture the prey and that selects for better defenses in the prey," she said. "Over evolutionary timescales, that causes gradual changes in both groups."