Tree frogs are go!
Hey everyone, this is Hannah and Becky and we are studying the climbing behaviour of metamorphosing tadpoles during our time in Trinidad. Our project is a continuation of research carried out over the last two years during previous expeditions.
In the wild metamorphosing tadpoles leave the water to reduce the risk of predation and to search for food. However this may increase their risk of desiccation (drying out) as it is unclear when metamorphs develop the same specialised skin adaptations found in adult tree frogs. They also have an increased surface area to volume ratio compared to adult tree frogs due to their small size, again increasing the risk of desiccation. We are investigating whether patterns of movement vary between species and whether the presence of shelter or other metamorphs affects an individual’s climbing behaviour.
We collect the tadpoles from various sites across Trinidad such as Caura Valley, Chicken Shack and Lopinot. The species caught so far include Hypsiboas crepitans, Trachycephalus venulosus, Phyllomedusa trinitatis and Hypsiboas boans. Once we have the tadpoles they are taken to the lab and looked after until they begin to metamorphose. As soon as we see the emergence of forelimbs (a sign that re-absorption of the tail is about to begin) the metamorphs are placed (either in singles or triplets) in a specially designed glass case. Each of the three cases are approximately 2m tall and are designed to allow us to film the movement of the metamorphs via digital cameras set up in the lab.
So far everything has gone very well; we have successfully set up the apparatus and have carried out several runs with different species both in singles and triplets. We hope to add more species to our list which could mean having to explore d’island further. All of our metamorphosed froglets have been successfully released back into the wild and are hopefully surviving well!
So far Phyllomedusa trinitatis (phylas for short) are my favourite metamorphs, they are relatively large, dark brown and take longer to complete metamorphosis than the other species. However once they’re fully grown they become beautiful bright green tree frogs. Becky on the other hand loves the little Hypsiboas crepitans (crepis) metamorphs who are very small and bright green. They metamorphose very quickly and are a lovely amber colour with pale brown mottling once fully grown.
Hannah and Becky