wildlife photographer of the year 2022

Highly Commended | Behaviour: Amphibians and Reptiles

THE DESCRIPTION

A male gliding treefrog, Agalychnis spurrelli, searches for mates and reproductive opportunities amidst thousands of potential offspring and competitors. Thousands of adults aggregate to reproduce on Costa Rica’s Osa Peninsula after torrential wet-season rainstorms over a large pond. On these rare nights, females lay hundreds of eggs, often right next to each other, creating huge egg masses on palm fronds that overhang forest pools, as seen here. Of the hundreds of thousands or even millions of eggs laid, most die from desiccation, predation, and fungal infection. Thus, single, unamplexed males fight for reproductive opportunities by attempting to dislodge amplexed males and take their place, or by trying to indirectly fertilize already laid eggs.

Agalychnis spurrelli is of particular scientific and personal interest because of its understudied arboreal explosive breeding strategy and the diverse behaviors that may affect reproductive success among adults. Agalychnis spurrelli is also a charismatic ambassador for treefrogs and amphibians everywhere. However, little is known about its natural history and behavior given that these events are hard to predict, rare, and occur at only a few remote locations. Moreover, hatching in this species is an excellent example of adaptive plasticity and environmentally cued hatching; embryos can hatch prematurely to escape predators, flooding, desiccation, and other egg threats. Lastly, gliding treefrog eggs are also extremely susceptible to desiccation and the increasing number of dry spells during rainy seasons in the tropics due to climate change are of concern for the survival of this species.

The backstory

I took this photograph during the first explosive breeding event I ever saw! I was so excited, amazed, and overwhelmed by the spectacular display of wildlife and animal behavior, that I had to try and capture as much of it as I could. That day, I took over 800 photos in less than 4 hours. I hope sharing this photo provides others with an opportunity to appreciate the chaos and beauty of this rare event.

In reality, this photo embodies the accumulation of over 5 years of remote field research. I have been studying the reproductive, behavioral, and developmental ecology of gliding treefrogs since 2017 for my Ph.D. dissertation research. Before beginning my field research, I visited and explored my field site in the hopes of seeing an explosive breeding event. I saw nothing but trace evidence that eggs were laid before I arrived. I went back in 2018 and took this photo during the first explosive breeding event I ever observed after waking up at 4 AM for days, waiting for this event to occur.

Explosive breeding events of gliding treefrogs are hard to predict, rare, and occur at only a few remote locations. I woke up at 4 AM for several days to survey the pond and look for breeding activity. To get this photo, I waded chest-deep through the murky 3000-meter-squared pond with all my camera and research equipment either on my back or in my hands. I fought off mosquitos and fumbled with my gear for over three hours, all while trying to avoid disturbing the two resident caimans that waited to prey on falling frogs from the vegetation above.

My favorite thing about this photo is how the intimate look of the focal male captures the intensity of his situation. Scrambling and partnerless amidst hundreds of thousands of already laid eggs and several competitors, this male’s gaze highlights the urgency of his need to reproduce. Explosive breeding causes mating mayhem since reproduction only takes place during short breeding periods. To me, this image captures the natural beauty surrounding this reproductive chaos.