Amphibious caterpillar facts for kids
Amphibious caterpillars are super unique insects found only in Hawaii. There are 12 different kinds of these caterpillars, and they are the only insects known that can live just as easily in water as they can on land! Imagine a caterpillar swimming around like a fish and then crawling onto a rock like a regular bug – that's what these amazing creatures do.
In 2010, two scientists, Daniel Rubinoff and Patrick Schmitz, from the University of Hawaii at Manoa, were the first to describe how these caterpillars live both in water and on land. These special caterpillars are actually the young (larvae) of a type of moth called Hyposmocoma. They belong to the moth family called Cosmopterigidae. Young caterpillars of each species can live happily underwater in fast-moving streams and also breathe air on rocks that stick out of the water. Rubinoff even said that these species are "at least as different as chimpanzees are from us," showing how special they are. While some other caterpillars can survive underwater for a short time, these Hawaiian caterpillars might be the only air-breathing animals that can truly thrive there for long periods. One scientist mentioned, "No other animal that breathes air can handle being submerged for a month."
What Makes Them Special?
These caterpillars don't have gills like fish, and they don't come up to the surface to breathe like marine mammals such as dolphins or whales. Instead, they seem to take in oxygen right through tiny holes in their "skin" from the water around them. Because they need a lot of oxygen, these caterpillars must live in flowing water, like streams. This moving water helps bring fresh oxygen to them. To keep from being washed away by the strong currents, they spin thin "silk" threads. They use these threads like ropes to attach themselves to the downstream side of rocks, holding on tight.
Their Unique Silk Homes
Amphibious caterpillars build special "cases" out of silk to cover themselves. These cases come in all sorts of cool shapes and sizes, and the caterpillars add to them as they grow. People have given them fun names based on what they look like, such as cones, bugles, burritos, cigars, candy wrappers, oyster shells, dog bones, and even bow ties! These silk homes protect them both in and out of the water.
A Long History in Hawaii
Scientists Rubinoff and Schmitz believe that the Hyposmocoma moths, which these caterpillars turn into, have been evolving in the Hawaiian Islands for about 20 million years. They figured this out by studying the genes of 89 different species and comparing them to the ages of the islands. Each type of amphibious caterpillar has only been found on one specific island, and usually only in one small area on that island. What's even more amazing is that this special ability to live in both water and on land developed three separate times in different groups of these moths over history.
