First Completely Monogamous Amphibian Identified – the Mimic Poison Frog

Genetic research has revealed that a fairly well-studied frog has been hiding an astonishing secret – pairs form lifelong pair bonds and remain faithful to one another.  Equally surprising is the fact that pool size alone (and not morality!) seems responsible for the fidelity shown by Mimic Poison Frog (Ranitomeya imitator) couples.  These findings, to be published in an upcoming issue of The American Naturalist, illustrate the second “first” for this species (please see below).

Teamwork in Raising the Young

Inhabiting wet forests in the foothills of the Peruvian Andes, male and female Mimic Poison Frogs must cooperate very closely if their young are to survive.  Males transport up to 6 tadpoles to individual pools at the bases of bromeliads (like all Dendrobatids, their eggs are deposited on land) and call to their mates when feeding time arrives.  The female then visits the pool and deposits an unfertilized egg, which is consumed by the tadpole.

The Effect of Pool Size

Interestingly, a close relative, the Variable Poison Frog (R. variabilis), does not exhibit mate fidelity despite dwelling in the same habitat and having a seemingly similar lifestyle (and appearance – Mimic Poison Frogs imitate the warning colors of this species).

However, the Variable Poison Frog deposits its tadpoles in large, nutrient-rich pools, where they mature without additional food from the female.  Without the unfertilized eggs supplied by the female, Mimic Poison Frog tadpoles would perish in the tiny pools that they inhabit…it seems that the strong bonds exhibited by the parents are essential to the tadpoles’ survival.

Another First – Imitating 3 Species

Monogamy is not the only surprise that this tiny frog has in store for us.  It is also the only amphibian known to exhibit “mimetic radiation”.  In all other amphibians that mimic the warning colors of other species, only 1 species is copied.  However, different populations of Mimic Poison Frogs imitate the warning colors of 3 distinct Poison Frog species.

With the array of complicated breeding strategies exhibited by frogs of the family Dendrobatidae, it’s save to assume that there are more interesting discoveries on the way…please write in with your own observations and theories.

Further Reading

You can learn more about this frog and its relatives on the website of the American Museum of Natural History.

 

 

R. ventrimaculata image referenced from wikipedia and originally posted by Thomas Ruedas