Spiderwebs Offer Scientists Unique Look at Animal DNA

As climate change and invasive species alter ecosystems around the world, scientists are racing to invent ways to quickly and efficiently record all of the animals in a region. Yet, as one research team found, it turns out nature may have designed the perfect method already: spiderwebs. 

Arachnids’ home bases are good at catching what experts call environmental DNA, or eDNA. eDNA is composed of tiny samples of all the biological matter animals shed as they move about their habitat. A tuft of hair? eDNA. A snotty sneeze? eDNA. Feces and urine? Yep, that’s eDNA too. All of it can be studied to see what species are roaming through a region. It can also reveal whether a species’ numbers are going up or down.   

Yet grabbing all of that e-info can be tricky. You’d need something that’s sticky, so it can catch all those castoff cells. It’d have to be easy to collect, and it should renew each day. It'd also need to not hurt the environment if removed to be studied. That’s where spiderwebs come in.  

"I've been told in my biology days that spiderwebs are sticky," Morten Allentoft, an evolutionary biologist at Curtin University in Australia, told NPR. "You can see they're messy, they're dirty. And I was thinking to myself, 'Maybe these (webs) are big passive air filters. They sit there for days or weeks — months even. They may very well be (snagging) the DNA that is floating around.'"  

In just one web gathered as part of a recent study, Allentoft found the DNA of 11 mammals (including kangaroos and wallabies), 13 species of bird, and many frogs and lizards. He hopes to use the data to map species movement and protect Australia’s native wildlife.    

Photo from Unsplash courtesy of Srivenkata Subramanian.

Reflect: In what ways do you think nature can help scientists understand and protect different ecosystems and the animals that live in them?