When most people think of silk, they picture spiders weaving delicate webs or caterpillars spinning protective cocoons. Some insect enthusiasts might even mention weaver ants or caddisflies.
But there’s another, often-overlooked silk producer living quietly under bark and leaf litter — the webspinner, a small, secretive insect that crafts silk not with its mouth or abdomen, but with its feet.
Silk at the Nanoscale
Webspinners, members of the order Embioptera, produce silk that’s unlike anything else in the natural world. “Webspinners produce the world’s finest silk — fibers on the nano-scale,” says Janice Edgerly, Ph.D., an insect behaviorist at Santa Clara University.
Some strands measure just 35 to 40 nanometers thick, finer than any spider’s web or silkworm thread ever studied.
Silk Spun by Foot
Each webspinner’s front tarsus — essentially its foot — contains dozens of microscopic silk glands. As the insect walks, it presses these glands against surfaces, releasing silk threads to create a network of tunnels.
These tunnels serve as both home and armor, protecting the fragile insects from predators, desiccation, and even rain. In some species, the silk coating acts almost like a waterproof jacket.
Studying Silk in Wet and Dry Worlds
In a recent study published in Environmental Entomology, Edgerly and her team explored how embiopteran silk interacts with water.
They compared silk from four webspinner species — two living on tropical tree bark and two from arid, underground habitats — to understand how different environments shape silk properties. Their research combined field collection with scanning electron microscopy in the lab.
Testing Water Behavior
In the experiment, webspinners were encouraged to spin silk across small grooved blocks. Once their silken shelters were complete, researchers placed tiny droplets of water on the silk and observed how the fibers reacted.
The results were striking: silk from tropical species formed smooth, dense films when wet, while silk from dryland species remained looser and patchier, with less cohesion.
The Surprising Science of Water Repellence
The team measured contact angles — the degree to which water beads up on a surface rather than soaking in — to gauge how hydrophobic each silk type was. One desert species, Haploembia tarsalis, displayed contact angles nearly identical to water-resistant materials.
Still, all species showed a unique transformation when wet: the fibers partially dissolved, fusing into a thin, shiny film.
A Living Raincoat
“Because of the silk’s protein composition and fine structure, it traps water between the threads, then transforms into a hydrophobic film,” Edgerly explains. “It’s slippery, shiny, and sheds water like an umbrella.”
The finding suggests webspinners have evolved silk that both absorbs and repels moisture, allowing them to survive in rain-soaked forests and arid soil alike.
Potential for Future Innovation
The study’s insights could have major implications for biomaterials science. Webspinner silk combines high crystallinity, nanoscopic fineness, and dynamic water interaction — properties that could inspire eco-friendly coatings, biodegradable textiles, or moisture-responsive materials.
The ability of the silk to shift from fiber to film could even inform the design of next-generation smart fabrics or self-healing surfaces.
The Complex Lives of Webspinners
Beyond their extraordinary silk, webspinners are full of behavioral surprises. Unlike most insects, they live in colonial groups led by females, who care for their young and maintain silk networks.
“Males don’t eat and play little social role,” says Edgerly. “It’s the females that build, tend colonies, and perform over 10,000 spinning steps in their daily routine.”
Small Insects, Big Discoveries
Edgerly’s decades of work have revealed just how intricate webspinner life can be. From their foot-spun silk tunnels to their community behaviors, these insects represent a marvel of quiet engineering. “They’ve evolved something entirely unique,” she says. “Their silk may be microscopic, but its beauty — and potential — is enormous.”
FAQs
What is webspinner silk made of?
Webspinner silk is composed of ultra-fine protein fibers, measuring as little as 35 nanometers in thickness. These fibers are secreted from glands located in the insects’ front feet and form tunnels used for protection and shelter.
How is webspinner silk different from spider silk?
Unlike spiders, which spin silk from their abdomens, webspinners produce silk from their feet. Their silk can also transform into a smooth, water-resistant film when wet, a property not observed in spider silk.
