One of our readers recently reached out to us from Hawaii, where she explained it has been very humid lately. She wrote, “I noticed this light brown bump about an inch and a half long on the ceiling in my bathroom last night. At first I thought it was ceiling damage, but then today I noticed a web hanging down from it. The web was covered in tiny larvae! Each larva was about 2 mm long and had a distinctive round black head. Any idea what they are?” She sent some fabulous pictures:
The first picture shows the light brown bump that she originally thought was ceiling damage. We think this dark spot might be the remains of a dead bug, where hundreds of moth eggs could have been deposited. We will explain this in more detail below. The next photo shows the string of larvae our reader found hanging from the ceiling:
We believe our reader is dealing with moth larvae! We think these are probably inchworms, which means they are the larvae of geometer moths. Adult moths lay their eggs in or near a food source for their larvae. Since these larvae eat decaying organic material, we think a bug could have died on the ceiling, and then a moth deposited her eggs in the decaying remains. When the eggs hatched, they didn’t have to search far for a food source and could simply begin eating! Some species of inchworms can produce silk, which is what the inchworms in this photo are hanging from.
So, how should our reader handle this situation? Well, since inchworms aren’t harmful or dangerous, she doesn’t need to panic! She can just wipe down the spot on her ceiling and use a cleaning agent spray to clear away any potential dead bug remains. Giving her bathroom a thorough cleaning also can’t hurt. She mentioned that it has been quite humid there, and the high moisture levels might be making her home more hospitable to larvae and other small organisms, since most generally prefer a damp environment. If possible, she can install a dehumidifier into her bathroom. She can also seal up any small cracks or gaps around her home to keep moths from flying in. Finally, she should make sure all of her windows and doors have a screen protection when left open!
In summary, we believe the string of larvae our reader discovered in her bathroom are moth larvae! They are harmless and aren’t typically destructive creatures inside a home, so our reader doesn’t need to lose any sleep over their presence. Cleaning her bathroom and sealing up potential entryways around her home should keep them from returning. We wish her the best of luck dealing with these specimens!