We've all eaten something that seems to run right through us, but rarely do our meals get to live another day once they leave our bodies. Yet that's exactly what happens when frogs snack on the aquatic beetle Regimbartia attenuata.
In a new study published Monday in the journal Current Biology, Kobe University ecologist Shinji Sugiura reveals more about the evolution of escape behavior in prey animals, most notably the aquatic beetle.
When the Pelophylax nigromaculatus frog gulps the beetle, it can survive by swimming through the frog's digestive tract to later be pooped out intact and alive. Previously, it was suspected frogs spit out beetles that moved so erratically.
Sugiura revealed that 93 percent of the beetles fed to a frog during the study escaped the frog's "vent" (anus) within four hours, "frequently entangled in fecal pellets." The quickest beetle escape was an impressive six minutes.
Because the aquatic beetle has evolved to become a better swimmer by kicking its legs and can breathe underwater by trapping a small pocket of air under its wing covers, the beetle may have also evolved to survive inside a frog's intestines long enough to escape through its captor's tush.
Of course, one has to wonder how the beetle gets the frogs to poop them out in a timely manner.
"Further experiments are needed to investigate how to stimulate the frogs to defecate," Sugiura told Wired. "However, I speculate that R. attenuata use legs and the body to stimulate the frog's hind gut."
While food crawling out of a frog's butt seems like a horrifying ordeal, that's nothing compared with the larvae of the beetle genus Epomis. When a frog eats Epomis larvae it releases enzymes that can melt the frog's flesh from the inside out.
"After a few hours the amphibian is reduced to just a pile of bones and just a little bit of skin," entomologist Gil Wizen told Wired in 2016.