Finding new species may call to mind images of scientists tracking mysterious footprints in the mud or cutting paths through the dense jungle.
But sometimes, a discovery is as easy as getting a frog to open its mouth and say, “Ah.”
Such is the case for Lenomyrmex hoelldobleri, a new tropical ant species found in the belly of a diablito, or little devil frog (Oophaga sylvatica), in Ecuador.
The diablito, a kind of bright orange poison frog, is known for its love of ants, says Christian Rabeling, a myrmecologist at the University of Rochester, New York. The new ant species is named after Bert Hölldobler, a German evolutionary biologist and ant expert, for his 80th birthday.
Because ant-eating frogs go hunting for bugs in tiny and hard-to-access places, scientists use them as a tool to go where they can’t go. By capturing a wild frog and flushing their stomachs, the amphibians vomit whatever is in their bellies—revealing potential treasures, like the new ant.
“Sometimes people think that our world is very well explored. Nothing could be farther from the truth,” says Rabeling, who led a new study on the ant, published September 19 by the journal ZooKeys.
Because the only known specimen of L. hoelldobleri is a dead one from a frog's stomach, scientists know almost nothing about it.
A glimpse through a high-powered stereomicroscope at that ill-fated ant, however, has offered a few clues.
“The shape of the mandibles reminds me of forceps,” says Rabeling. This may mean that the ant, which is less than a quarter of an inch long, uses its mouthparts to pry even smaller prey animals, such as termites, out of tight crevices. “But I am just speculating,” he admits.
Since scientists have only one specimen of the ant, its biology is almost completely unknown [Image: C. Rabeling & J. Sosa-Calvo]
If the scientists could find living L. hoelldobleri in the Ecuadoran rain forest, the team they could submit the little guys to a “cafeteria test," which means offering an animal multiple prey items to see what it prefers.
“The difficulty is finding the ants!” says Rabeling.
The little devil frog, obviously, has figured out how to locate them—and for good reason.
Poison frogs get their namesake chemical defenses from alkaloids found in the ants and other critters they consume, says Jonathan Kolby, a National Geographic grantee and director of the Honduras Amphibian Rescue and Conservation Center.
"Physiologists regard ants as mini chemical factories," adds Rabeling. The insects likely use the chemicals as signals to communicate with other ants in their complex societies.
As for where the ants get their alkaloids, Kolby says some species may acquire it from the plants they eat. But what role, if any, L. hoelldobleri may play in the poison game is anyone’s guess.
Belly of the Beast
Because many amphibians are endangered—the International Union for Conservation of Nature lists O. sylvatica as near threatened—any research with wild frogs must be done carefully, and only by trained experts, Rabeling notes.
To flush the stomach, scientists insert a soft tube into the amphibian’s mouth and gently fill it with water, prompting whatever the frog has eaten recently to flow out of its mouth and onto a tray. The frog can then be safely returned to its natural habitat.
This is not the first time a new species has been found inside another animal’s stomach, by the way. Kolby points to the example of Dunn’s earth snake (Geophis dunni), which was found in the stomach of a coral snake (Micrurus nigrocinctus) in Nicaragua in 1932.
Furthermore, it seems L. hoelldobleri had some company in the little devil frog’s stomach. The research project that first identified the new ant also found several other as-of-yet undescribed insects.
It seems the little devil’s frog's belly might be the gift that keeps on giving.