Welcome to the spiderverse, a world measured through webs

Scientists studying biodiversity have identified spiderwebs as a highly effective substrate for collecting environmental DNA, or eDNA — genetic material shed by living organisms into their surroundings — per a report by MIT Technology Review. The finding opens a potential new avenue for wildlife monitoring that requires no active trapping or direct observation.

eDNA sampling has grown significantly over the past decade, with biologists analyzing genetic material from soil, water, air, and animal scat to track endangered and invasive species. Spiderwebs, naturally sticky and widely distributed, trap not only material from the spiders themselves but also saliva, pollen, and airborne bio-detritus from nearby plants and animals — making them a passive collection device for the surrounding ecosystem. Joshua Newton, a molecular ecologist at Curtin University in Perth, Australia, described webs to MIT Technology Review as "probably one of the best substrates we've used and tried to date."

Newton compared biological diversity detected in spiderwebs against several other collection methods — vegetation swabs, water samples, soil samples, and a fan fitted with a filter — near a zoo and wildlife sanctuary outside Perth. While each method had specific strengths (vegetation swabs captured more forest mammals; water samples identified more fish), no passive tool matched spiderwebs for identifying vertebrates overall. A similar study conducted in France echoed those results.

There is a significant drawback, however: gathering meaningful data required destroying approximately 40 webs per sampling effort. "It kind of goes against everything that we're trying to do if we're collecting the home of an organism," Newton told MIT Technology Review.

That problem prompted Angela McGaughran, a genomicist at the University of Waikato in New Zealand, to test a low-tech alternative. She purchased synthetic Halloween webs, stretched them over coat hangers, and hung them outdoors. The artificial material successfully captured eDNA from nearby cows and sheep, detected exotic birds from a neighboring aviary, and outperformed real webs at capturing fungal spores — a finding with direct relevance for plant pathologists monitoring agricultural threats.

McGaughran's group is now designing larger experiments to assess whether synthetic webs can replicate the eDNA-trapping performance of natural ones at scale, per MIT Technology Review. If validated, the approach could offer conservation programs a cheap, deployable, and non-destructive monitoring tool for use across diverse environments.