We were recently doing some major remodeling in our 1920s era home and found what looks like a nest of small meal worms. I am wondering if anybody can identify them! Here are some photos:
Our home is in Denver CO. I didn't see any living examples so it is possible they have been there for nearly 100 years.
1 Answer
You are correct!, those are definitely mealworms. If you're not already aware, mealworms prefer to live in dark places (so under/in woodwork is expected) and typically eat decaying material, but are also partial to consuming new plant growth.
During the larval stage of a mealworm (of which will eventually grow into a Darkling Beetle), a mealworm will undergo 10-15 molts before pupating. That being said, the collection of carapaces that are shown in your picture is probably the work of just a few beetles.
I cannot attest as to how long it takes for a mealworm carapace to deteriorate, but sure, those remains could very well have been there for decades. If the location in which you found these remains has a dirt floor, you could possibly try identifying trails that were left by the developed beetles. Their trails looks like this: