For romantic flies looking to make some fly babies, bats are the ultimate buzzkill. Those big batty ears are incredibly adept at picking out the sounds of fly love. Aided by the flies’ precoital “clicks,” the bat swoops in for the two-for-one kill.
Previous studies of freshwater amphipods, water striders, and locusts have shown that mating can make animals more vulnerable to predators, but these studies did not determine why.
For the bats, it’s all about the sound. Normally, bats use echolocation to locate prey. But flies in this study were sitting (relatively) stationary on a barnyard roof, so that tactic doesn’t work. Unfortunately for the flies, the bats had a backup plan.
That’s when passive acoustic cues, or the sounds that prey make, come into play. The team noted that the male made a clicking sound with his wings before copulating that alerted the bats to the pair’s location. These clicks were between 9 kHz and 154 kHz and came in 3-second bursts. So to humans, whose hearing maxes out around 20 kHz, the clicks sound like low-frequency buzzing. But to bats, which can hear sounds up to 150 kHz, the clicks are clear auditory alerts.
The bats snatched up 26 percent of copulating flies, munching on both male and female flies about 60 percent of the time.
Humans like to think we invented star-crossed lovers, but this research suggests dying for a chance at amour has probably been going on since long before the debut of Romeo and Juliet.
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