![]() ![]() This adhesive system is distinct from that of other well-studied underwater glue-makers, such as mussels and sea cucumbers, and may offer a unique path forward for researchers trying to engineer an underwater fixative.Īs for the ribbon component of caddisfly silk, it’s resilient, somewhat like a rubber band. Interestingly, unlike our glues, which generally work better on clean, dry surfaces (like skin), caddisfly glue bonds more readily to bio-fouled surfaces, those already coated with decaying matter and bacteria from the stream. As these bonds form, they displace the water where the tape meets the stone, allowing the two substances to stick together. Though its mechanism isn’t fully understood, the glue part of caddisfly tape forms highly complex bonds, both chemical and physical, with whatever it’s sticking to. From the materials science standpoint, caddisfly tape is extraordinary in both departments. (Josh Cassidy/KQED)Īny tape, including this one, has two basic components: the flat ribbon, or backing, and the layer of sticky stuff, or the glue. Inside its case, the caddisfly is safe from the powerful forces of its streambed habitat, as well as from predators. “And when they get to building, they are very selective.”Īfter carefully choosing a starter pebble for its case, the caddisfly meticulously tapes more and more stones together, and the case begins to take shape.Ĭalifornia is home to approximately 400 species of caddisflies, and there are some 15,000 worldwide, all of whom use some version of the silk. “They come out immediately and start,” said Patina Mendez, a researcher who studies caddisflies at UC Berkeley. The case-building behavior begins as soon as the caddisflies hatch. The natural tape of the caddisfly holds together its case, even underwater. “It’s an extremely fancy tape,” said Russell Stewart, an expert on caddisfly silk also at the University of Utah. Thanks to the qualities of that silk, the case not only holds up underwater, it is strong enough to protect the caddisfly’s soft lower body amid forces many times its body weight. The tape, really a specialized silk, comes from a pair of glands under its chin. In its larval stage, this industrious builder constructs a tiny tube-like house for itself, called a case, entirely underwater using pebbles and its tape as the mortar. (Josh Cassidy/KQED)Įnter the caddisfly, a stream-dwelling insect equipped with a homespun waterproof tape dispenser. The caddisfly builds a case out of pebbles to live in during its larval stage. ![]() “The second you go inside the body, it changes the ball game entirely,” said Ashton. Our insides are as fluid as fish tanks, and hostile to chemical adhesives, so doctors use mechanical means to mend bones and sew up internal tissues. The inside of the human body is a watery environment. “Typically we can make an adhesive bond that is stable underwater,” said Nicholas Ashton, a bioengineering researcher at the University of Utah. ![]()
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