by Josh Newton is probably not very popular with spiders. After all, the Australian scientist has a tendency to get around without doing their hard work.
“I like it with Princess Fiona in it Shrek she makes cotton candy for Shrek from a spider fetus, where she collects a stick and makes it straight around the spider’s web. But I do it with a clean, sterile stick,” said Newton, a PhD candidate in life sciences at Curtin University As It happens hosted by Nil Köksal.
“And then I just wrap the spider and put it in a little tube and bring it back to the lab.”
But he has a good reason. Spiders, it turns out, trap more than unwitting bugs. The sticky surfaces also contain a bounty of genetic material from dozens of animal species that live nearby – making them a powerful tool for measuring biodiversity.
In a new study, Newtown and colleagues identified DNA from 93 different invertebrates in spider webs in Perth, Australia. The results were published last week in the journal iScience.
You are breathing DNA right now
The study is just the latest innovation in the emerging scientific field of studying environmental DNA (eDNA) – genetic material that all living creatures lose as they move around the world, often in the form of cells dead skin.
In recent years, scientists have collected DNA from soil, water, plants and more. It can even be drawn from the air.
Earlier this year, conservationists used environmental DNAto locate a species of golden mole in South Africa that was feared to be extinct.
“Everything seems to be covered in environmental DNA,” said Elizabeth Clare, a molecular ecologist at Toronto’s York University who was not involved in the study. “Every breath of air you breathe contains DNA.”
An Austracantha minax spider spins a web at the Karakamia Sanctuary, the wildlife sanctuary where Newton and his colleagues conducted the first part of their study. (Submitted by Joshua Newton)
Newton says the idea to check spider webs for animal DNA came from his PhD supervisor, Morten Allentoft.
“He was walking in a wetland near where we live and saw a huge web, and it kind of just kind of clicked. And he thought, ‘Oh, surely this is going to work.’ “
Scientists have used webs to collect the DNA before, but only the spiders that built them, and the insects they prey on. This is the first time researchers have extracted invertebrate DNA from webs.
They first collected webs from an animal sanctuary in Perth, and identified DNA from 32 different species, including native mammals and birds.
But scientists don’t know how far eDNA travels, or how long it lasts, so the researchers couldn’t be sure that the DNA they got from animals living nearby present.
So they repeated the experiment at Perth Zoo. Sure enough, they found DNA from 61 different invertebrate species that, for the most part, matched the makeup of the zoo.
“So, elephants and rhinos and kangaroos in the spider webs,” said Newton.
Clare says the study’s authors helped solve some of the mysteries of eDNA by doing research at a zoo – where they knew exactly where the animals were located in relation to the webs.
“We really lack information about how long the [genetic] the material can move, and its persistence,” she said.
Quick, cheap and easy
Mark Louie Lopez, a University of Victoria researcher working with first nations to monitor eDNA in Alberta lakes, says using webs to collect DNA is a smart innovation.
Often, he says, collecting genetic material on land means swiping trees and leaves, taking soil samples, or studying blood-sucking creatures like leeches and mosquitoes.
“Collecting spider webs is a much faster method … and it also avoids issues arising from the presence of organic inhibitors (for example, tannins found in the soil) that make DNA more difficult to detect,” said Lopez, iTrackDNA and Liber Ero postdoctoral fellow. CBC in email.
“It’s amazing how creative researchers are using eDNA for biodiversity monitoring.”
Clare and Lopez caution that eDNA alone has a limited scope. For example, you can tell what animals are around, but not how many. So measuring biodiversity is just one tool in the scientific toolbox.
Currently, one of the most powerful methods of collecting airborne DNA is extracting it from air filters — a technique pioneered by Clare and her colleagues.
SEE | York University scientists collect eDNA from air filters:
But filters require electricity. And scientists have to install them, or collaborate with the countries and governments that are already implementing them.
“This is a little simpler,” Newton said. “We’re walking out into the environment and the spider webs are just there and they’re very easy to collect. And they’re everywhere, a lot, spiders.”
Everyone has a win, he says — except, perhaps, the hard-working spiders.
“It would be nice to find something that worked as well that didn’t affect the spider,” Newton said. “We are working on that.”
