Table of Contents
An exciting new discovery
In 2020 herpetologist Carlos Henrique de-Oliveira-Nogueira and his team were working in the coastal forests of Brazil when they noticed something fascinating — a small, brownish-orange colored frog was drinking the nectar produced by the flowers of the Brazilian milk fruit tree (de-Oliveira-Nogueira et al. 2023). One might expect frogs to mostly catch and eat insects, with their long and sticky tongues. However, Izecksohn’s Brazilian tree frog (Xenohyla truncata), is one of the few frog species known to consume both the fruits and flowers of plants. But the teams observations revealed even more about this discovery.
To drink the nectar, the frogs dipped their entire bodies into the white bell-shaped flowers of the milk fruit tree. After drinking, the researchers noticed a powdery substance stuck all over the frogs’ bodies – it was pollen produced by the male parts of the flower. The scientists were thrilled by this observation because this meant that the frog could be a very special type of ‘pollinator’. Pollinators are animals that help flowering plants ‘pollinate’, a crucial process for plant reproduction. But how do pollinators facilitate this process?
Understanding pollination
Many plant species reproduce in the following manner: (1) they produce flowers, (2) the flowers develop into fruits, (3) the fruits contain seeds and (4) once they mature, the seeds travel away from the parent plant to grow into new plants. The male parts of a flower, known as ‘anthers’ produce pollen grains- the same substance that the scientists observed on the Brazilian tree frog. For a flower to turn into a fruit with seeds these pollen grains must be transported from the anthers to the female part of a flower called the ‘stigma’). This process is called pollination.
But pollination is not always easy for plants! This is because the anthers and stigmas can often be located far apart from each other— either on separate flowers of a plant or even on an entirely different plant. So how do plants get pollen to the stigma? This is where pollinators come in!
Pollinators: The animal superheroes of the plant world
Flowers rely on a number of different methods to transport their pollen. Wind and water are sometimes capable of loosening up and moving pollen grains, which can by chance settle down on anthers of the same species. But there are also many animals — like birds, bats, bees and butterflies that visit plants and their flowers. And they happen to be very important for plant pollination! Animals visit flowers to sip on the sweet nectar that flowers produce. Or even to eat and collect the pollen grains on the anthers of the flower. The nectar and pollen provide strength and energy to these animals, keeping them coming back for more. But something else happens when animals feed on flowers — unknown to them the sticky pollen grains get attached to their bodies and are carried to other flowers that the animal visits. And when the animal visits the next flower to feed, the stuck pollen grains have a chance of falling off and landing on the stigma of the flower, allowing pollination to happen! These animals that help in pollination are called ‘pollinators’.
Pollinators are very important for many plants — without them many flowering plants would not be able to reproduce and would no longer exist. The most well-known and popular pollinators are honeybees, which are capable of visiting up to a 100 flowers in a day! We have known for a long time that insects, birds (like hummingbirds and sunbirds) and even mammals (like nectar-feeding bats) pollinate flowers (Regan et al. 2015). But the finding by de-Oliveira-Nogueira’s team could potentially be the discovery of world’s first known amphibian pollinator! If the Brazilian tree frog visits other flowers of the same plant after enjoying the nectar from one, it would mean that they are transferring pollen grains between flowers and increasing chances of pollination, helping the milk fruit tree reproduce. The discovery of this fruit and flower visiting frog is truly a unique one!
What does this discovery signify?
Scientists have not yet proved for sure that the Izecksohn’s Brazilian tree frog pollinates the milk fruit tree. But they are investigating to better understand this behaviour. Nevertheless, this discovery has shown us that there is a lot we still don’t know about the natural world — and that there is still much to explore! The unexpected interaction between the tree frog and milk tree also adds to our growing knowledge of pollinators — some other surprising pollinators that were discovered recently were lizards, rats and cockroaches! This shows us how important many animals are to plants and how diverse these relationships can be.
As for the frog itself, Xenohyla truncata is a species that is considered to be vulnerable to extinction . This animal is often overlooked because of its small size and elusive nature. The discovery of this frogs pollination habits could show the world how important this frog species is and get it the attention it deserves. And most importantly, it goes to show that there is a lot left to discover and learn about the world around us!
Flesch Kincaid Grade Level: 10.08
Flesch Kincaid Reading Ease: 56.02
Glossary
Amphibian — An organism that is able to live on land and water, mostly including animals like frogs and salamanders
Herpetologist — A scientist who studies reptiles (like snakes, crocodiles and turtles) and amphibians
Extinction — The dying out of a species
References
Shurkin, Joel. “Animals that self-medicate.” Proceedings of the National Academy of Sciences 111.49 (2014): 17339-17341.
Regan, E. C., Santini, L., Ingwall‐King, L., Hoffmann, M., Rondinini, C., Symes, A., … & Butchart, S. H. (2015). Global trends in the status of bird and mammal pollinators. Conservation letters, 8(6), 397-403.
de-Oliveira-Nogueira, C. H., Souza, U. F., Machado, T. M., Figueiredo-de-Andrade, C. A., Mônico, A. T., Sazima, I., … & Toledo, L. F. (2023). Between fruits, flowers and nectar: The extraordinary diet of the frog Xenohyla truncata. Food Webs, 35, e00281.
https://blog.nature.org/2023/07/05/frogs-as-pollinators/
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