Z is for Zetek’s Treefrog
This brilliant photo of this little treefrog was taken by Dr Robert Puschendorf, Lecturer in Conservation Biology at Plymouth University, and is used by permission.
Here it is again, peeking out from a bromeliad, so you can see where it lives – this gorgeous photo was taken by Andreas Hertz and is also used by permission:
These are the only images I could find of this little frog, so I’m very grateful to both these scientists for allowing me to use their photos.
It is a small (less than 3cm) Zetek’s treefrog that lives in Costa Rica and western Panama, at 1,200-1,800m above sea level, in cloud forests.
To be more specific, they live in bromeliads, in the water the cup-like leaves hold, and bromeliads grow high on trees – bromeliads are not a parasite on the tree, they gain all their nutrients and water from the atmosphere.
Zetek’s frogs lay their eggs above the waterline of the bromeliad’s interior, and when ready the tadpoles fall into the water – uniquely, the tadpoles are flattened and shaped like a guitar when seen from above.
Their tadpoles, that have been dissected, had eggs in their stomach – so it is possible that in common with other frogs that live in bromeliads (where unlike in a stream, there is nothing for the tadpoles to live upon), the mother revisits the pools and lays unfertilised eggs in the water for the tadpoles to eat.
Because they live so high in the trees, they were only discovered by tracing the male’s unique mating call – 5 pulsed notes that last about 4 seconds.
In Costa Rica their population appears to be stable, but it is thought they are suffering from habitat loss in Panama.
All treefrogs are at risk from the chytrid (Chytridiomycosis) fungus. The fungus is capable of causing sporadic deaths in some amphibian populations and 100% mortality in others. No effective measure is known for control of the disease in wild populations. It has been called “the worst infectious disease ever recorded among vertebrates in terms of the number of species impacted, and it’s propensity to drive them to extinction.” (Gascon et al, 2007).
This disease is thought to have originated in frogs caught in Africa, where it has been known for a long time, that were caught for pets or used for pregnancy testing in laboratories, that may have escaped or been moved to new locations, so it is now threatening populations in areas which have little immunity.
Dr Andreas Hertz, who took the second photo above, works at a laboratory that is looking for a way to advance probiotic strategies to mitigate the effects of chytridiomycosis in wild amphibian populations. (I’m pretty certain this means using microorganisms to help kill off the fungus or strengthen the immune response in the frogs).
Treefrogs are particularly at risk from deforestation, and sometimes species are only discovered when their trees are cut down.
Zetek’s treefrog is classified Near Threatened by the IUCN Red List for Threatened Species.
How our needs subsume those of every other species on the planet!
Here is my very last poem for the 2016 A-Z:
Just one tall tree
among the trees,
a scoop of water
furled in leaves,
an ant or two
on which to feed,
is all the world
a treefrog needs,
just one small part
of forest’s song –
but when trees fall
and all are gone,
rains turn flood,
earth turns stones,
and in the dust
a treefrog’s bones.
© Liz Brownlee
Gascon C., J.P. Collins, R.D. Moore et al., editors: Amphibian Conservation Action Plan. IUCN/SSC Amphibian Specialist Group. Gland, Switzerland and Cambridge UK, 2007.