Humans didn't want to go into this mysterious jungle in Asia, so they sent a drone in instead

Humans didn't want to go into this mysterious jungle in Asia, so they sent a drone in instead

The drone had a winch attached to it – and on the end of the winch was a probe, used to collet DNA. Here's what the researchers were up to...

Published: December 3, 2024 at 7:56 am

Many animals live within the high canopies of Southeast Asia's lush rainforests – from tiny, inconspicuous insects and scuttling spiders, to vivacious Old World monkeys.

But the sheer height of the trees and dense foliage that adorns them makes analysing this enigmatic world somewhat of a challenge.

One way to learn more about these arboreal creatures is through their DNA, traces of which they leave behind on leaves and branches as they swing, slither and clamber through the canopies.

But how do people collect this DNA without damaging the very habitat they're trying to protect?

Scientists now say they have developed a novel way to gather this genetic material: a drone equipped with a specialised fabric probe.

According to research published in Environmental Science & Technology by the American Chemical Society, this method has successfully been used to identify invertebrates and other creatures living in the rainforest canopy.

“If we want people to protect nature, we need to tell them what we are actually protecting," says lead author Steffen Kirchgeorg.

"Traditional methods, such as surface swabbing, are labour-intensive and require significant effort to achieve adequate coverage," says Kirchgeorg, explaining that these techniques can be invasive, causing damage to trees and impacting the behaviour of the animals. "With our solution, we hope to better understand the life in the canopy.”

Watch: the drone releases a specialised probe in the rainforest to collect environmental DNA from the trees’ branches and leaves/Adapted from Environmental Science & Technology 2024

DNA-collecting drones

Drones are increasingly used to access places humans can’t easily reach, from remote wildernesses to delicate ecosystems where footfall would be harmful.

These aerial devices can photograph landscapes, monitor environmental conditions, and now, collect DNA from the forest canopy. Known as environmental DNA (eDNA), this genetic material originates from sources such as mucus, faeces and dead skin cells.

While drones equipped with swabs have previously been used for this purpose, their potential to damage both the drone and vegetation during collisions has posed challenges. In response, Kirchgeorg and colleagues, including Stefano Mintchev, designed a safer and more efficient system.

The new setup features a drone fitted with a fabric probe designed to gently brush against branches and leaves, collecting eDNA without harm.

Operated by a remote pilot, the probe is attached to a tether that can be lowered and raised via a pulley system. The probe itself resembles a circular fleece cloth – similar in shape to a coffee filter – with fibreglass strips providing structure. A sensor detects any impacts with vegetation, allowing the system to adjust its position before completing a collection.

Long-tailed macaque
DNA from the long-tailed macaque (Macaca fascicularis) was found during the study/Getty

What the drone found - and why it's important

In proof-of-concept trials conducted in the Central Catchment Nature Reserve, Singapore's largest nature reserve, the drone completed ten sampling missions, venturing beyond the researchers’ line of sight. Upon returning, the fabric probes were removed, and the eDNA extracted for analysis.

The samples revealed a rich variety of organisms, predominantly insects and arachnids. Among the more notable discoveries were a long-tailed macaque, multiple species of ants and termites, and a gall midge fly.

This innovative approach offers a new way to explore biodiversity in hard-to-reach habitats. The researchers emphasise that understanding these ecosystems is vital for conservation and restoration efforts, ensuring these remarkable species and their habitats are safeguarded for the future.

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