Beetles, eaten by frogs, can run right out of their butts: study

It’s a new kind of dung beetle.

Beetles have an unorthodox way to escape frogs after getting eaten — by ducking out the back door, according to a Japanese study published in the journal Current Biology.

According to the first-of-its-kind research, the water scavenger beetle, Regimbartia attenuata, climbs down its captor’s intestinal tract and forces the captor to poop it out, which can take anywhere from six minutes to two days. The fecal defense mechanism can be observed in this stomach-churning YouTube video.

“I do not want to eat this beetle if I’m a frog,” study author Shinji Sugiura told the New York Times. The Kobe University biologist engineered the study to test “unimaginable” prey defenses after noticing that both amphibians and the scavenger beetles inhabited the same rice paddies in Japan.

In accordance, he fed a beetle to a frog in the lab, expecting the amphibian to expel it from its mouth — as is the case with many frog-beetle encounters. However, the scientist was shocked when the bug came out the other end instead.

To ensure the laxative tactic wasn’t a fluke, Sugiura tested the phenomenon out with five different species of bug-gobbling frogs in the lab. He found that “90% of swallowed beetles were excreted within 6 h (0.1–6.0 h) after being eaten,” per the study.

The researcher can’t pinpoint what causes the frog to poop out its prey. However, when he pinioned the beetle legs with wax, all “were killed in the frogs’ digestive system and finally excreted” within 24 hours of consumption.

Sugiura deduced that “swallowed beetles likely used their legs to move through the digestive tract” and swim toward the exit. He suspects that their hardy carapaces might help protect against the frog’s digestive juices as well — as evidenced by the fact that amphibian excrement is often riddled with beetle parts.

“That a little beetle can actively swim through a digestive system is peculiar and amazing,” Carla Bardua, an evolutionary biologist at London’s Natural History Museum, told the New York Times.

R. attenuata escaping from the vent of P. nigromaculatusSuccess rates of the escape of Regimbartia attenuata from five frog species.An adult of the aquatic beetle Regimbartia attenuatafrog-beetle-16

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