Ask The Entomologist

Ask The Entomologist: What’s this bug in my breakfast?

“This guy and its buddy were both about 5 mm (1/5 inch) long, in my Malt-O-Meal.”

Excellent question, and an attractive little fellow it is.
This furry worm-like beastie is a larder beetle larva, a member of family Dermestidae.

If you’ve ever watched a criminal mystery program on television, you’ve probably seen these insects’ relatives make an appearance with forensic entomologists. Dermestid beetles are often used to clean meat off bones, whether for criminal investigations or by folks who prepare skull mounts. They’re better than chemical treatments, as they leave no markings on the bones themselves, and can be stopped before they destroy the connective tissues holding the creature together.

While entomologists call these things dermestid beetles, there’s a variety of names for them, depending on the species and what they like to eat. Often the bone-cleaning ones are called hide beetles” or “skin beetles The household stored-product pest names you might be familiar with are larder beetles or carpet beetles. As these names imply, there’s quite a bit of variation in what these insects eat.

These insects are survivors. Many species of dermestid beetle occupy some of the worst, least-tasty carcasses out there… These beetles tend to come late to bodies, after most of the good juicy bits have been eaten or have spoiled. I’ve found dermestid larvae between dry ocean fish vertebrae, inside a variety of mammal skulls, as well as in the dried out bodies of little things like mice, songbirds and lizards.

While some species can be helpful at times, most can become pests, especially to taxidermists or fur preparers. It’s an absolute nightmare trying to get dermestid beetles out of museum collections – they’re happy to eat just about anything dry and once living – aged fabrics and hide clothing, pressed plant specimens in herbariums, as well as taxidermied animals (skins as well as hairs or feathers). They don’t discriminate between vertebrates and invertebrates either – dermestid beetles are quite happy to eat pinned insect collections, too.

This three-color band pattern is very common in dermestid beetles.
This particular individual is a true larder beetle, found in my sack of short-grain sticky rice.

Some dermestids have found that sacks of grain are to their liking as well. Here’s a stowaway I found in one of my sacks of rice recently – a diet much more similar to that of your malt-o-meal beetle. It stands to reason, of course – they’re the same species, Dermestes lardarius.

Should you have problems with these in your own home, both Colorado State University and The Ohio State University have made nice informational sheets on how to control larder beetles and other dermestids.
CSU’s dermestid info & control sheet & OSU’s dermestid info & control sheet.
If they should get into your emergency food cache, though, don’t worry. They’re good eating.

And a closeup – this adult larder beetle is just a little bit bigger than the larva in the ID request photo.
Just over 1/4th inch, as opposed to 1/5th of an inch.

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