Chomp! Being eaten by another animal usually spells doom for most bugs—but not for Regimbartia attenuata, a species of water beetle. After being swallowed by a frog, this tough little insect manages to pass through the amphibian’s entire digestive system, until it emerges alive and kicking from the frog’s rear end!
Shinji Sugiura, a biologist at Kobe University in Japan, studies insect survival behaviors. He discovered the beetles’ ability by collecting them, along with frogs that prey on them, from rice paddy fields. He placed the animals together in a plastic bin to study how the beetles might defend themselves. As expected, the frogs promptly ate the bugs. But within minutes, 90 percent of the beetles wiggled out of the frogs’ butts. “I was surprised to see that,” says Sugiura.
Sugiura wondered: How could the insects survive in a frog’s digestive tract, which has no oxygen to breathe and is filled with digestive juices that break down food? Water beetles carry their own oxygen supply by trapping air under their exoskeleton. This hard outer shell also acts like a suit of armor, protecting the beetle from the frog’s harsh digestive juices.
The beetles’ quick transit also suggests that they don’t just wait around to be pooped out. It’s likely the bugs crawl through the frog’s gut to speed things along and make their escape. Apart from being covered in frog droppings, the bugs don’t seem harmed by their ordeal, says Sugiura. Once free, the beetles simply swim away . . . possibly to be eaten and pooped out another day!