Tinneola Bisselliella, the Clothes Moth. Photo from Wikipedia Commons.
In a recent reorganization of some of the Arboretum Office’s collections, Arb director Nancy Braker and student naturalists discovered a surprise in the owl pellets drawer. The bottom of the drawer was filled with frass (insect excrement) as well as small cocoons, indicating that some sort of insect had been living in the pellets. “It’s an Arb Office mystery!” Braker declared. After further examination and research, she determined that the intruding insect was most likely Tineola bisselliella, a species of moth commonly referred to as a “clothes moth.”
Clothes moths get their name from the fact that their larvae often feed on fabrics and rugs. They consume cotton, silk, linen, and fur, but they prefer wool. Due to the damage they cause, they are generally regarded as pests and are often deterred with mothballs. This has become less of a problem recently due to the moth-proofing of wool and the explosion of synthetic fibers used in clothing. In the natural world, the larvae play a unique role in decomposing the keratin in the hair of dead animals, a compound that few other decomposers can break down.
Not all of these moths feed on fabric or hair, however. Ceratophaga vicinella, a member of the Tineidae family, consumes only the keratin shell of dead gopher tortoises. The larvae construct a series of silk tubes under the shell that extend underground, anchoring the shell in place. These tubes offer them protection during the larval and pupal stages of their development. The moth’s range covers the southeastern United States in areas where gopher tortoises are found. However, tortoise populations have been threatened recently, due to road mortality and a widespread respiratory disease, causing moth populations to decline, as well.
This “Arb Office mystery” shows that many species we regard as pests often play important ecological roles and may have close relatives that need our protection. We can learn a lot from a little frass!
- Maddie Reynolds ’14, for the Cole Student Naturalists