Sex and food are the two main drivers of evolutionary invention -- which means roughly half of all biological adaptations are inspired by the ongoing battle between predator and prey.

The lengthy tail of the luna moth is one such adaptation. New research reveals that the tail works to deflect and distract the sonar detection capabilities of the bats for whom the insect is a preferred nighttime snack.

Like fake eyes that appear on fish, or on the outer wings of other butterfly and moth species, the kite-like tail that flutters off the bottom of the luna moth distracts predators from more vital and vulnerable parts of the body. Unlike eye spots, the moth's tail is an auditory defense mechanism. Its swooshing and fluttering create auditory static that distracts bats' echolocation systems.

The overarching premise is not entirely new.

"Again and again may predator bat or bird, in an effort to capture a moth or butterfly, successively tear away sections of the tails, of which a sacrifice can be readily afforded, without disabling it or retarding its flight," biologist Archibald Weeks wrote in 1903.

But new research by Jesse Barber, a scientist at Boise State University, confirms the confusion that the luna moth's tail causes. In a controlled experiment, Barber put moths and bats together in a dark room. Under normal circumstances, bats were only able to snag 35 percent of the moths. When Barber cut the moths' tails off beforehand, the bats' success rate jumped to 81 percent.

"Our finding suggests that focusing on the sensory ecologies of key predators will reveal such countermeasures in prey," the researchers wrote in the abstract of their new study, published this week in the journal PNAS.