Fireflies don’t just glow for sex – they do it to warn away bats too | Artificial intelligence
Fireflies don’t only light up their behinds to woo mates – they also do it to tell predatory bats to keep away.
This twist in the tale of the trait that gives fireflies their name was discovered by Jesse Barber at Boise State University in Idaho and his colleagues. The characteristic benefits both fireflies and bats, because these insects taste disgusting to the mammals. When swallowed, chemicals emitted by fireflies cause bats to vomit them back up, meaning both species are keen to avoid such an interaction.
Researchers placed eight bats in a dark room with three to four fireflies plus three times as many palatable insects, including beetles and moths, for four days. During the first night, all the bats captured at least one firefly. But by the fourth night, most bats had learned to avoid fireflies and catch all the other prey instead. When the team painted fireflies’ light organs dark, a new set of bats took twice as long to learn to avoid them.
“This is the first time we have good experimental data on the warning displays of fireflies,” Barber says.
It had long been thought that fireflies’ bioluminescence mainly acted as a mating signal, but the new finding explains why firefly larvae also glow despite being sexually immature.
But bats don’t depend on bioluminescence alone to avoid making a meal of an unpalatable firefly. The team also found bats can use echolocation to distinguish fireflies from other insects by their wingbeat rate. “The ability of bats to use combined sensory system to detect fireflies is truly amazing,” Barber says.
Journal reference: Science Advances, DOI: 10.1126/sciadv.aat6601.
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