03/1/10

First Monogamous Frogs Discovered

This past week the first monogamous frogs were discovered in the rainforest of South America. Monogamy isn’t usual in the amphibian world. Male frogs usually love ’em and leave ’em.

But Dr. Jason Brown, previously of East Carolina University, Greenville, North Carolina, and his colleagues, discovered a monogamous frog species Ranitomeya imitator, known as the mimic poison frog,

According to the BBC Earth News article, “Peru Poison Frog Reveals Secret of Monogamy,” after mating, a female mimic poison frog lays her eggs on the surface of leaves. After the tadpoles hatch, the male frog carries them one by one on his back to pools of water that collect in bromeliad leaves high up in the branches of trees. Each tadpole is put into its own tiny pool and the father looks after them. When the tadpoles become hungry, the male calls to his female partner who lays a non-fertile egg, which the tadpole eats, in each pool.

Why are these frogs monogamous and others aren’t? Scientists believe the mimic poison frogs have become mongamous as they evolved to live in small pools. The frogs wouldn’t have survived without the care of both mother and father because there is little natural food in these tiny pools. If the pools were bigger, there would have been more available food and the the frogs wouldn’t have to work together to feed and raise the tadpoles.

“These frogs are truly devoted to their offspring, and to each other,” says Dr. Brown, who is now at Duke University.

Father and mother R. imitator frogs guard a leaf pool where the mother just deposited a nutritious egg for the tadpole to eat. Photo by Jason Brown, from Science magazine site

Father and mother R. imitator frogs guard a leaf pool where the mother just deposited a nutritious egg for the tadpole to eat. Photo by Jason Brown, from Science magazine site

Image from ScienceNOW blog (Science magazine)