Scientists say spider webs may act as air filters that capture environmental DNA from terrestrial vertebrates.
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Scientists say spider webs may act as air filters that capture environmental DNA from terrestrial vertebrates.
Rob Stothard/Getty Images
The rich tapestry of life on Earth is fraying, largely due to human-induced habitat loss and climate change. As more species disappear, researchers are racing to track the global decline in biodiversity, understand its impacts and counter it through conservation efforts.
These efforts rely on accurate animal monitoring, which can be difficult, time-consuming, and expensive.Now, a new study published in the journal iscienceresearchers present evidence of spider webs, a new low-cost, non-invasive tool that can be used to monitor animals.
Here's how things worked for a while: If you want to know which animals are in a particular location, hike or climb into their habitat and wait to see or hear them. However, this approach can have drawbacks.
“When you're repeatedly entering hostile environments to conduct visual inspections,” says Josh Newton, Ph.D. “It's a bit difficult,” says Genetic Biodiversity student at Curtin University in Perth, Australia.
Another issue with traditional monitoring is that it may involve capturing animals. “It's stressful for the animals,” Newton said. “It's not great and it's not what you want to do, especially if you're looking for rare or endangered species.”
DNA is everywhere
In recent years, scientists have turned to other ways to monitor biodiversity. They use environmental DNA (eDNA). This is simply the DNA of different organisms present in the environment. You can think of this as the ecological version of “everywhere at once.”
“All species that exist are[s] Curtin University evolutionary biologist Morten Allentoft said: “In a given environment, in a given ecosystem, they die, rot, urinate, defecate, breathe, do all sorts of things. The authors state that this series of processes “promotes cell shedding.” All cells contain DNA. ”
Researchers have detected eDNA by swabbing it from leaves and flowers, filtering it from water, extracting it from the air, and even finding it in the intestines of dung beetles and the blood of leeches.
One day, as Allentoft was walking around Lake Bibra in his Perth home, he noticed a pile of giant webs built by spiders that weaved golden orbs in the trees.
“When I was studying biology, I was taught that spider webs exist. [are] “It’s sticky,” he said with a laugh. And I thought to myself, “Maybe it's this spider web.” [are] Large passive air filter. They sit there for days, weeks, and even months. They are very likely capturing DNA. [is] It's floating.''
Previous studies have shown that webs are a good source of insect DNA, including that which spiders devour. But Allentoft and Newton wanted to see if the nests were capturing vertebrate DNA, perhaps blown away by the wind or deposited by insects.
Kangaroos, wallabies, oh!
So Newton drove to Karakamia Wildlife Reserve, a wooded area about 30 miles outside Perth, and collected cobwebs from branches and bushes. “When I looked at it shrek The process is very similar to Princess Fiona's collection of spider web fairy floss for Shrek. “You just grab a stick and wrap it around,” Newton says.
Dr Josh Newton A genetic biodiversity student at Curtin University in Perth, Australia, collects the golden orbs that weave spider webs.
Morten Allentoft
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Morten Allentoft
Dr Josh Newton A genetic biodiversity student at Curtin University in Perth, Australia, collects the golden orbs that weave spider webs.
Morten Allentoft
Even if the webs were dismantled, the spiders were never harmed or recovered. “We just gently coaxed them off the web,” Newton says.
Of course, it's unclear what the spiders thought of this approach.
“That's why we say it's non-invasive,” Allentoft added with a laugh.
Back in the lab, Newton amplified a small amount of DNA from the web. They were filled with genetic material from animals Down Under.
“It was amazing,” Allentoft said. “We could see these kangaroos [and] In addition to wallabies, there were nine other mammals, 13 species of birds, a biker frog, and a snake-eyed lizard. Analysis of the forest also detected DNA from red foxes, mice, and black rats. It does not belong to Australia.
To ensure Webb was collecting DNA from local animals, Newton also collected samples at Perth Zoo. And those nests contained DNA from 21 birds, five reptiles, two amphibians, and 33 mammals, including giraffes, elephants, rhinos, orangutans, lemurs, and meerkats.
In other words, the technique worked. This represents a new way to track animal biodiversity and alert when to intervene to protect native species and step up efforts to eliminate invasive species.
“I think it's smart and cute,” says Elizabeth Clare, a molecular ecologist at York University in Toronto who was not involved in the study. “This is a great way to non-invasively sample terrestrial vertebrates. There are thousands of papers that have studied the movement of DNA in water, but very few on land. We need to do more research like this: how it accumulates and how long these signals last.”
For example, Newton doesn't know whether the nests he collected have been around for days, weeks, or months. However, some orb spiders build a new nest every night and destroy it in the morning. “Imagine he could collect DNA from spider webs,” Allentoft said. “Then they'll have a very accurate picture of what species are actually out there right now.”
Next, Newton and Allentoft plan to investigate how the placement and shelf life of different types of spider webs can tell them which animals are roaming nearby. This is their version of the World Wide Web, and it's packed with equally important information.
