Mites Keep Cockroaches Mold-Free

Bugs on Bugs A cockroach viewed under a scanning electron microscope reveals one-millimeter-long mites that live on it to eat debris and keep it clean (well, for a cockroach, anyway). Jay Yoder

What’s more disgusting than cockroaches? Mites that feed off cockroaches. Here, mites munch moist debris from around the breathing holes of a Madagascar hissing cockroach, an insect sometimes kept as a pet that, unfortunately, can trigger allergies.

It turns out that eliminating this damp debris reduces mold growth, making the cockroach less of an allergen. Joshua Benoit, a doctoral student in entomology at Ohio State University, had previously determined that the cockroaches harbor some 14 different species of mold, and he noticed that the roaches also harbored mites. He set out to study the relationship between the cockroaches and mites, but his research shifted to mold once he discovered the stowaways’ hidden benefit.