Francesca Del Fico The first fruit-eating amphibian discovered in Rio de Janeiro which, by dispersing the seeds, becomes a potential pollinator
@Henrique Nogueira/Twitter
While amongst land vertebrates, mammals and birds serve major ecological roles as pollinators and dispersers, frogs never have received a good word in this regard since the majority of species are carnivorous-after all, largely insectivorous-since metamorphosis. Still, there is an exceptional representative: Xenohyla truncata, an actively frugiferous and floriferous, even nectariovorous-an insect no different from bees and the like, capable of the quality of pollination.
An Amphibian Rarity in the Atlantic Forest, Xenohyla truncata, is a small frog-a little less than 2 inches-that was discovered last year by Brazilian researchers. Native to the Atlantic Forest, particularly the sandy areas of Rio de Janeiro, it is already considered an endangered species due to the rampant urban expansion that is threatening its habitat.
Most of the time, these frogs remain inside sheltered bromeliads, colorful tropical plants. These types of frogs feed not only on insects but also on plant materials and nectar.
A closer look into its diet
Scientists earlier studied the stomach contents of this species and found it to include invertebrates with several plant structures. In a recent study, scientists discovered more:
We recently discovered surprising associations of this neotropical tree frog with plants within its native range. Frogs ingested all plant types: fruits, floral structures, and nectar-all obtained by sucking. The pollen grains that attached on the back suggest a new function for this animal as a possible pollinator in addition to the earlier recorded role of seed disperser. Individuals in reproduction stage could take advantage from the energetic income obtained during nectar consumption. It constitutes a strange and exceptional case among unexpected associations between anuran and plant species.
A seed disperser and a potential pollinator
The fact that Xenohyla truncata is able to eat fruit makes it a very efficient seed disperser while its relationship with flowers renders it the first known amphibian to serve as a pollinator. The scientists have been able to film the frog eating plant matter, small fruits, as well as petals. Some of them have also been filmed sucking on nectar in flowers.
The most striking observation was the frog’s behaviour of entering larger flowers in order to reach nectar, and upon leaving often with grains of pollen on its dorsum-an unmistakable sign that here was a potential pollinator.
Unanswered questions and future research
While groundbreaking, this did raise a number of questions: just how such frogs have peculiar adaptations to take up nectar, or whether all of the plant species available to them would even be digestible. The newly published study inaugurates their work toward the fully rounded investigation that such amphibians need.
Sources: Food Webs / Professor Henrique Nogueira
