Here’s something to remember next time you’re grousing about the long line at your favorite sandwich shop: Some animals have to put up with a lot more to secure a tasty lunch. Case in point, a study out today shows the head-on strategy that certain frogs will take to wrap their tongues around a hornet-shaped meal.
Scientist Shinji Sugiura studied whether the black-spotted pond frog (Pelophylax nigromaculatus) would actively hunt various species of hornet wasps, including the so-called murder hornet. Not only did the frogs voraciously gulp down the insects, but they did so while easily surviving the hornets’ venomous stings. The frogs’ natural ability to endure venom lethal to plenty of mammals, humans included, could possibly teach us a thing or two, the researcher says.
“If pond frogs do possess physiological mechanisms that suppress pain or resist hornet venom, understanding them could one day help us develop new ways to reduce pain or inflammation in humans,” Sugiura, an ecologist at Kobe University in Japan, told Gizmodo in an email.
A chance discovery
Sugiura wasn’t initially planning to explore the venom-busting powers of pond frogs. But during an earlier study of how mason wasps defended themselves, he and his colleagues used frogs as one of the predators. They then noticed the frogs could handily prey on female wasps that possessed a venomous stinger (only female wasps have stingers that inject venom, but the team’s research showed that male mason wasps can use their penises as a sort of non-venomous stinger).
A series of images showing a black-spotted pond frog easily eating a hornet. Images C and D show the hornet’s stinger embedded in the frog’s mouth. © Shinji Sugiura/Ecosphere
That observation made Sugiura curious enough to dig deeper on his own. Adult hornets have been found inside the stomachs of various frogs, including P. nigromaculatus, indicating that frogs will sometimes eat them in the wild. But the question remained: Do frogs eat these hornets while desperately trying to avoid their stings, or in spite of them? To find out, Sugiura set up an experimental buffet.
He collected black-spotted pond frogs of various sizes and left them alone with female workers from three hornet species: Vespa simillima, V. analis, and V. mandarinia. That last species is called the northern giant hornet, aka the murder hornet. Though their nickname is mostly derived from how viciously the hornets hunt bees, their painful stings do occasionally kill humans. It’s also the largest species of hornet and was briefly an invasive threat in North America several years ago.
Across the board, the frogs were plenty interested in munching down the hornets, and they weren’t afraid to get stung for their trouble. They also usually managed to eat their prey; the lowest capture rate was seen with V. mandarinia, at 79%.
“By using a large number of individual frogs, I quantitatively showed that many of them successfully captured and consumed hornets even while being stung,” Sugiura said. “Hornet stingers are powerful weapons that are generally thought to deter most predators, yet these results reveal that some animals can tolerate such venomous attacks and still prey on these insects.”
Sugiura’s findings were published Thursday in the journal Ecosphere.
Lessons to be learned
The frogs appeared to shake off the venomous stings with no apparent harm. That said, it’s still unclear exactly how they’re tanking them.
Hornet stings are known to be incredibly painful and sometimes lethal to mammals like us. But it’s possible the complex mix of toxins naturally produced by these wasps doesn’t affect an amphibian’s biology all that much. Or perhaps frogs have evolved traits that make them less vulnerable to the venom or make them feel much less pain from a sting than a typical mammal would.
No matter the hornet species, the frogs still usually got their lunch. © Shinji Sugiura/Ecosphere
Whatever the case might be, understanding these frogs’ antivenom defenses could certainly lead to important new discoveries. Next, Sugiura is planning to study whether pond frogs can easily withstand the venomous stingers of other arthropods (insects, arachnids, and other creepy-crawlies). And in the future, he’d like to experimentally test just how tolerant frogs are of a hornet’s sting.
Sugiura also hopes his current work can demonstrate that even the ferocious murder hornet isn’t exempt from being part of the food chain.
“I believe this finding offers a surprising insight for the general public, showing that even one of the most dangerous insects in the world is not entirely safe from predation,” he said.
