House of Frass – Insects by Julie Craves
We are long overdue in painting the exterior of our house. Not only would we like to sell it in the next year or two, but of course we feel how our house looks reflects upon us. And “shabby,” “peeling,” and “fading” are not how we like to describe ourselves.
Things could be worse. Let’s say we were the larvae of one of the Cryptocephalinae, or case-bearing leaf beetles. Our “home” (the case) would be made from our own excrement. We all know the longer we live in a house, the more crap we accumulate. In the case of these beetle larvae, this true in a very literal sense. Toting around an abode made of your own turds is a good way to be unobtrusive to predators while in a vulnerable state – or completely unappealing if discovered. In many species, the adult beetles are quite attractive, reward for spending the beginning of their lives covered in their own waste.
Some members of another subfamily of leaf beetles follow a similar lifestyle, such as the tortoise beetles. These insects don’t construct quite as solid a structure, but nonetheless do create external self-protection. We recently came across some Thistle Tortiose Beetles (Cassida rubiginosa) on Canada Thistle (Cirsium arvense); neither species is native to North America. Most of the beetle larvae were festooned with frass (the official term for insect poop). Some were not, and looked like spiny trilobites. Either way, creepy.
The larvae of insects in a completely different family, the Green Lacewings (Chrysopidae) also have spiny exteriors and decorate themselves with debris. These predatory larvae are a bit more catholic in their use of materials. There may be some frass, but usually they use bits of plants and body parts of recent victims. In any event, all of these mobile homes serve as disguise or protection or both.
Many insects utilize convenient substances in the creation of temporary housing. These are just a few examples of the ones that are making do by making doo.