Some fleas do not poop for weeks. This keeps their pools clean

Some tadpoles do not poop in the first weeks of their lives. At least, this is the case for Eiffinger’s tree frogs (Kurixalus eiffingeri), scientists report on September 22 at Ecology.

Eiffinger tree frogs are small frogs that live in Taiwan and two Japanese islands: Ishigaki and Iriomote. Tree-dwelling amphibians lay their eggs in small pools, which are often found in plant stems, tree hollows, and bamboo trunks.

After hatchlings, they spend their early life in these ponds. However, in pools as small as these, there isn’t much water to dilute the ammonia – a toxic chemical that animals release when they urinate or defecate.

Bun Ito and Yasukazu Okada, biologists from Nagoya University in Japan, have now discovered chickens’ secret hygiene strategy – self-induced constipation. Tadpoles store their excrement in a gut pouch until they begin to metamorphose into full-fledged frogs.

Ito and Okada raised tadpoles from four different species of frogs in makeshift nurseries. After the experiment began, they moved the chickens to smaller cribs, plastic boxes with little more than a tablespoon of water. The team measured and compared how much ammonia each species emitted. They also measured the amount of ammonia stored in the guts of each species.

Eiffinger tree frog tadpoles released on average less than half the amount of ammonia as the species that released the most. And compared to two of the other species, chickens carried more ammonia in their guts. The researchers note that unlike Eiffinger’s tree frogs, other species typically lay their eggs in open ponds where ammonia easily dilutes.

“The behavior likely serves to prevent pollution of small bodies of water,” says Ito. Some ammonia still seeped into the tree frogs’ water, potentially through their urine.

It turns out that Eiffinger tree frog tadpoles have another superpower: Experiments showed that they can survive higher concentrations of ammonia than any of the other species included in the study. Dryophytes japonicus, better known as the Japanese tree frog. While this may seem counterintuitive, given the no-lunch period of shrews, Ito notes that chickens sometimes share their beds with other animals, such as mosquito larvae, which also release ammonia.

“We hypothesize that chickens have developed a tolerance to ammonia as a dual defense mechanism,” says Ito, “both against ammonia produced by other organisms and ammonia they produce themselves.”