Week One

We are spending the next two months studying reproductive plasticity in Dendropsophus ebraccatus (also known as the hourglass tree frog or the pant-less tree frog!). These frogs show an unusual tendency to lay eggs both in the water and terrestrially, which has some interesting implications for understanding the evolution of eggs that don’t depend on being in water to survive. We are placing breeding pairs in controlled field cages, and trying to isolate females who really prefer to lay their eggs in water, or prefer not to. We will keep the frogs in captivity here, and breed them again, to make sure we are finding the extremes. These lucky frogs get a plane ticket back to New York with us at the end of July to form a breeding colony at Vassar. Through longer term artificial selection we are hoping to be able to try to find the genetic basis for this phenotypic variation. Phoebe will also be building her senior thesis at Vassar off of this project by testing ebraccatus tadpoles raised with different predators  for behavioral variation, and then setting them up in a choice test with each predator to determine how, if at all, this variation affects their survival.

A male Dendropsophus ebraccatus calling in attempt to attract a female.

We spent a lot of time this week making trips to the hardware store for materials, and then constructing the cages. All of our cages and general materials are made out of storage boxes, window screen, dog pools and all kinds of crazy stuff. We built shelves in the lab out of long planks of wood and cinder blocks. We also collected grasses and floating plants to go in our artificial ponds.
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Phoebe and Annie with one of the six cages we built.


Hubert after digging up soil for our plants.

On Tuesday, we caught our first two pairs of frogs for the experiment. Although we’ve been searching out D. ebraccatus, we have also been having a blast learning all the different frog calls and tracing them back to the frogs, our tally is over 10 species as of right now! We have also had a lot of fun with every new species, and have found some pretty crazy spiders, insects, lizards, and snakes.

Annie holding a cat-eyed snake.


Phoebe with a red eyed tree frog (Genus: Agalychnis)


Hubert with a basilisk lizard, which has the ability to run on the water’s surface.

Although most of our time has been spent with the frogs, we have had some time off to explore the area. We’ve hiked some of the local trails, cooled down at the pool at the Rainforest resort, and visited the animals at the the Summit Zoo. We’ve also gotten the opportunity to attend several talks about different subjects in tropical ecology. 



A Harpy Eagle at the Summit Zoo


View of the pool at the Gamboa Rainforest Resort

After spending much of this week on set up, the experiment is in full swing! We will spend the next few weeks catching more ebraccatus pairs for our mating trials, as well as beginning the tadpole experiments. More updates to come!