Nestled among the channels of the man-made Gatun Lake, part of the Panama Canal, lies Barro Colorado Island (BCI). On the remote six-square-mile enclave, amongst pristine tropical rainforest, sits a research station where wildlife photographer and scientist Christian Ziegler works at the juncture between research and photography.

Christian is perhaps best known for his images of tropical bats. Over two decades, he has battled jungles bursting with biting insects to document the incredible biodiversity of the Central American rainforests. "I started working with and photographing bats nearly 20 years ago with an amazing bat researcher, Dr Elisabeth Kalko," he says. "I still find bats interesting today – there are over 80 species where I live in central Panama."

A tropical ecologist by training, Christian has previously worked as an associate for communication with the Smithsonian Tropical Research Institute (STRI) in Panama. STRI staff use the BCI base to document climate and animal diversity and to monitor the rainforest. The different bat species' varied diets aid plant pollination and help to control the insects that can damage crops, so Christian was tasked with providing scientific evidence, alongside arresting imagery, to promote the positive contribution they make to Panama's environment.

To capture the nocturnal mammals in their natural habitat, Christian frequently turns to his Canon Speedlite 430EX III-RT flash. Here he explains how he does it.

A careful balance of light

Christian makes a note of the lighting he needs to create the look he wants for each shot, and admits it can sometimes be a lengthy process, even when coaxing a bat into position with food. However, once the bat is in place, he can quickly adjust each of the five Canon Speedlite 430EX III-RT flashes with the Canon Speedlite Transmitter ST-E3-RT. Crucially, using a transmitter means he's not moving around and disturbing the bat. He adjusts the power settings in 1/3 steps for each flash individually via the built-in RF transmitter locked in position on the camera's hotshoe.

"I start with the flash from the top," explains Christian. "Once that looks good, I adjust the two flashes from the front. One is about a metre above and one about a metre below the subject at 45-degree angles, lighting the wings from below and the bat's face from above. The remaining two flashes are positioned behind, both below the bats, to give a sharp edge and separate the bats from the background."

The scientists use a flight cage – a large space enclosed by netting – to prevent the bat flying away. The bat's welfare is paramount. "It's important on a scientific level, as well as morally, that the resulting photographs are authentic," Christian says.

If the photographs need to include an insect, the team will find one that's already dead. But if Christian is photographing a pollinating bat, he must first find the right flower for the shot, which can take time. "In one case, to take photos of nectar-eating bats, I needed the bat-pollinated flower of the liana woody vine. But it took around a week to find suitable mature flowers in the forest," he says.

The resulting series is testament to the team's tenacity under trying conditions, and a lasting record of biodiversity in an isolated tropical ecosystem. Christian hopes this kind of photography can teach people about the world around them, informing them about environmental challenges and, ultimately, inspiring change for the better.

"So many species and habitats are threatened worldwide, and many species are on the point of extinction," he says. "I want to get people excited about the jungle. If they understand how the ecosystem works, hopefully they will value it more."