SAN DIEGO, CA—Recent studies have revealed that spiders are capturing wildlife DNA, which can be used to identify the kinds of animals living or visiting the place where those spiders exist. Environmental DNA (or eDNA) is the genetic material that living things shed into the environment through their skin, hair cells, or other bodily residues. It is often sampled from water and soil, but scientists have recently turned their eyes to an often-overlooked sticky surface in nature: spiderwebs.
“Spiderwebs behave like a piece of tape hanging midair,” shared Dr. Rachel Larson, postdoctoral researcher at the San Diego Natural History Museum. “DNA particles that are floating in the wind can be carried and trapped in the web—we’re sampling what's lodged in there.”
In collaboration with the Willette Lab of Applied Ecology at Loyola Marymount University, scientists at the San Diego Natural History Museum are using spiderwebs to learn more about the biodiversity that exists in San Diego County’s urban canyons. After sampling the webs, they’re sent to the lab for analysis, and so far, the results have been astounding. From 48 samples, they've detected at least 50 unique species, including gray fox, garden slender salamander, and birds, such as the lesser nighthawk (all of which are difficult to find using traditional surveys).
“Spiderwebs are gathering an immense amount of biological information,” said Dr. Demian Willette, professor of biology at LMU Frank R. Seaver College of Science and Engineering. “In a previous study, my research team and I detected over 200 species from webs collected in an urban park just east of downtown LA, roughly three times the number of species we observed in visual surveys.”
While eDNA research is not emerging, the use of spiderwebs as a sample medium is. Scientists are looking to the webs as a way to passively gather data and complement traditional on-the-ground survey methods. They estimate that a sample of four spiderwebs can yield up to 34 different taxa, or species. In fact, collecting eDNA from spiderwebs is so practical and effective that scientists trained community members that live near urban canyons on how to sample the webs as part of a larger effort to conserve these green spaces.
Local residents are getting in on the action, too. The Healthy Canyons Initiative seeks to document the state of biodiversity in San Diego County's urban canyons to help inform conservation actions. Scientists are training and working alongside local community members to gather data on the plants and wildlife living in the canyons. Through the power of community science, residents are making plant and wildlife observations on iNaturalist, setting up bird recorders in their yard, and most recently, sampling spiderwebs for eDNA. The community science research complements the extensive biological surveys being led by Museum scientists in more than 20 canyons throughout the county.
Like much emerging research, there are still many questions the scientists are asking, like how far eDNA can travel in the wind, or what kinds of spiders create the best webs to capture eDNA particles. While the science for spiderweb eDNA sampling isn’t quite yet perfected, scientists are continuing to experiment with sampling methods and study sites. In the meantime, one thing is certain: spiders are catching more than just their dinner.
To learn more about the Healthy Canyons Initiative and how to contribute as a community scientist, click here.
The San Diego Natural History Museum (The Nat) is one of California’s oldest and most respected cultural and scientific institutions. Founded in 1874 by a small group of community scientists, the Museum works to preserve and protect this amazing place we call home. The Museum is located at 1788 El Prado, San Diego, CA 92101 in Balboa Park. For more information, call 877.946.7797 or visit sdnat.org. Follow The Nat on Instagram, Facebook, TikTok, and LinkedIn.
The Willette Lab of Applied Ecology at LMU Frank R. Seaver College of Science and Engineering strives to advance science education and pursues solutions to current environmental problems. The lab’s research focuses on conservation in both marine and terrestrial environments, including restoring native biodiversity, managing invasive species, and combatting Illegal, Unreported, and Unregulated (IUU) fishing and seafood fraud. The lab’s work cuts across disciplines and utilizes principles and approaches from the fields of ecology, molecular genetics, ecological modeling, and environmental policy. Learn more by visiting the lab website.
Loyola Marymount University is one of the nation’s top 10 Catholic schools and is ranked 6th among California’s private colleges and universities in the latest edition of U.S. News and World Report’s Best Colleges. Founded in 1911 and rooted in the Catholic, Jesuit, and Marymount traditions, LMU enrolls 7,100 undergraduates and 3,000 graduate and law students across seven colleges and schools. The university offers 56 undergraduate majors, 57 minors, 43 master’s degree programs, three doctorate programs, and 12 credential/authorization programs. With top-ranked programs in law, film and television, entrepreneurship, business, and the arts, LMU is embedded in the creative, cultural, and economic life of Los Angeles. The university generates $1.4 billion in annual economic impact. A proud member of the West Coast Conference, LMU fields 14 NCAA Division I teams and competes with purpose, pride, and integrity. LMU news and events are found at: www.lmu.edu/news.
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For media inquiries or interview requests, please contact:
Paula Sternberg, Science Communications Manager, psternberg@sdnhm.org, 619.255.0220