A team of researchers from the University of Notre Dame has successfully identified the species of a spider from a sample collected from the arachnid's web. The team was also able to pinpoint the species of the prey using the method, which could have a range of practical applications.

DNA sampling allows scientists to exactly identify subject species, but it's generally pretty invasive, requiring a sample to be drawn directly from the organism in question. Now, the researchers have come up with a way of uncovering the DNA of spiders and insects, in a truly non-invasive manner.

Rather than looking directly at the creatures, the team looked to the webs that they produce. Taking samples from black widows at Potawatomi Zoo in South Bend, Indiana, the researchers worked to amplify and sequence the mitochondrial DNA, with the results not only identifying the spider that produced the web, but also showing the species of its prey – in this case, the crickets used as a food source.

Furthermore, the method remained effective over a long period of time, with analysis correctly identifying the two species for some 88 days after the point where living organisms were no longer present on the web.

The findings aren't just academically interesting, but could also lead to practical applications. Most significantly, they pave the way for biomonitoring without the need to directly monitor or interfere with organisms.

"Sticky spider webs are natural DNA samplers, trapping nearby insects and other things blowing in the wind," said team member Charles Cong Yang Xu. "We see potential for broad environmental monitoring because spiders build webs in so many places."

The findings of the research were published in the journal PLOS One.