A reader wrote to us recently about some extremely small larvae that appear to have white bodies and black heads. She found a “few dozen” white-bodied, black-headed larvae in her bathroom; they were in a damp towel that was on the edge of the bathtub, and larvae fell on the floor when the towel was unfolded. The reader speculated that she might have found moth fly larvae, but she wanted to check her tentative identification with us because the larvae she found seem even smaller than moth fly larvae. Given where the larvae were found, we think it is possible she found moth fly larvae, but because of their appearance, she also might have found Indian Mealmoth (pantry moth) larvae. Below we discuss both possibilities.
As you can see, the larva above is extremely small – it looks tiny even relative to the tip of the pen in the photo. It is hard to see, but if you look really closely, it appears that larvae has a black head that is facing downward, and the rest of its body is a lighter color.
Regardless of what these creatures are, we are fairly certain they are the exact same creatures that three other readers have written to us about, as described in the following articles:
The different language in each title reflects the wording of the questions we received, so although we talk about both larvae and “worms,” as well as white and dark bodies, these are all articles about very small larvae with black heads and lighter-colored bodies. In all of these articles, we speculated that our readers found moth fly larvae or Indian Mealmoth larvae because these seem to be the most likely possibilities.
In general, Indian Mealmoth larvae are more noted for the contrast between their black heads and white (or whitish) bodies. Moth fly larvae can look similar, but often their entire bodies are a dark, grayish color, and thus they don’t really have particularly distinct black heads. However, in this case we think it is more likely our reader found moth fly larvae because of the environment in which they were found, namely, a damp place in a bathroom, which is precisely where one would expect to find moth fly larvae. Moth fly larvae are most commonly found in drains – indeed, they are often called drain fly larvae – but it isn’t hard to imagine that they might settle in a damp towel hanging on the bathtub’s edge, which is presumably not far from a drain anyway. In contrast, Indian Mealmoth larvae would generally be found in a pantry near dry foods (cereal, grains, etc.). Moreover, moth fly larvae tend to be only a few millimeters long, whereas Indian Mealmoth larvae are three or four times larger, and while the creature pictured above still seems especially small, it is more in the “moth fly larvae” range than the “Indian Mealmoth larvae” range.
In short, a damp towel in the bathroom is certainly more amenable to moth fly larvae than to Indian Mealmoth larvae, and moth fly larvae are smaller than Indian Mealmoth larvae, so we think it is more likely our reader found moth fly larvae, which is what she thought she might have found to begin with. That said, identifying larvae is always tricky because so many larvae look so similar. Thus, even though we think moth fly larvae and Indian Mealmoth larvae are definitely possibilities, our reader should note that she could be dealing with something else. Regardless of what she is finding, we hope she is only dealing with a one-time problem that she is able to take care of swiftly.