Musings on moldy bugs

Last fall, my swamp cooler acted up and everything in my apartment ended up getting moldy.  I found mold on a hat that was packed away in a closet, growing on my interior doors and cabinets, on a piece of jewelry made with natural materials, books, and sundry other objects.  Much to my horror, I also found a box of bugs in my collection had gotten moldy.  There are several things you don’t want to see when you look at your insect collection.  Damaged specimens that have been handled improperly or dropped (especially by someone else who didn’t tell you they did it) are always bad.  Carpet beetles get into your collection and eat all of your bugs.  That’s right – some bugs eat dead bugs!  Carpet beetles are the scourge of most entomological collections and can decimate an otherwise perfect collection in a very short period of time.  Most insect collectors use mothballs or cyanide-based chemicals to protect their collections from carpet beetles.

Mold isn’t something you want to see in your collection either.  I recently got around to attempting to clean off the moldy bugs in an effort to save them and, oddly enough, I learned some very interesting things in the process.  There seemed to be a nifty connection between the habits of a particular bug and the amount of mold that grew on it.  For example, this bug is a carrion beetle:

carrion beetle

Carrion beetle

I pulled it off a dead snake I found out in the field several years ago.  (Dead animals are an excellent source of insects!)  Carrion beetles are decomposers and eat dead, rotting things.  Needless to say, this insect was wallowing around in nasty things when it was alive, all kinds of bacteria and molds that were helping break the snake down as it rotted.  When I cleaned the mold from my insect collection, the carrion beetle was completely covered, as in 1/4 of an inch thick across it’s back!  I couldn’t even tell it WAS a carrion beetle until I cleaned it off.  When I thought about it later, it made sense to me that it would be one of the bugs with the most mold.  It lived in rotting animals and likely picked up some mold spores while it was eating its dinner.

Among the less moldy bugs was this wasp:

velvet ant

Velvet ant, a type of wasp

It makes sense that this bug didn’t have much mold on it if you know something about it.  In this photo is a wasp called a velvet ant.  This particular type of wasp is a parasite that stings other insects to paralyze them and then lays its eggs inside the still living body of its victim.  The larval wasps eat the insect as they develop.  The adult eats nectar.  This wasp isn’t crawling around inside the rotting remains of a dead animal and likely barely touches things that have a lot of bacteria and molds growing on them.  It makes sense, then, that this insect wouldn’t have as much mold living on it when I put it in my collection compared to the carrion beetle that was living in a soup of mold spores and bacteria.

Another bug with very little mold was this giant water bug:

Lethocerus medius

Giant water bug

It’s typical to dispatch aquatic insects in alcohol, so this guy was soaked in an antiseptic liquid for a time before it was pinned.  It makes sense that this insect wouldn’t have much mold on it’s body for this reason and indeed it had less mold on its body than any of the other insects.  Based on the amount of mold on this insect compared to the others in the box, I came up with a plan for how to clean them: alcohol.

So, I cleaned all of the insects in the box of moldy insects one by one with a paintbrush dipped in alcohol to counteract the mold build-up.  It worked for now, but we’ll see if it comes back this summer.  But for now my collection is looking pretty good once again.  This is what you want to see when you have a collection:

My collection

One unsorted box of my insect collection

A nice clean box of insects, free of live bugs and mold!


Text and images copyright © 2009