Sunday, August 07, 2011
Ever see these things around your house?
They look like little gray seeds, laying innocently among the dirt and stuff on your porch or patio.
They have tiny caterpillars inside.
This is the larva of the case bearing moth, Phereoeca uterella, and right now I am finding them around my house.
From their BugGuide page:
The larval case is silk-lined inside and open at both ends. The case is constructed by the earliest larval stage (1st instar) before it hatches, and is enlarged by each successive instar. In constructing the case, the larva secretes silk to build an arch attached at both ends to the substrate. Very small particles of sand, soil, iron rust, insect droppings, arthropod remains, hairs and other fibers are added on the outside. The inside of the arch is lined exclusively by silk, and is gradually extended to form a tunnel, while the larva stays inside. The tunnel is closed beneath by the larva to form a tube free from the substrate, and open at both ends. After the first case is completed, the larva starts moving around, pulling its case behind. With each molt, the larva enlarges its case. Later cases are flattened and widest in the middle, allowing the larva to turn around inside.
[from Featured Creatures, U. of Florida]
They eat spider webs, of all things, but will also eat wool things like carpets and clothing if the opportunity arises (like if the moths get into the house!) I also seem to recall reading somewhere that they like to eat dog hair, which I have plenty of around the house.