Living with carpet beetles

Over the past year or two, winter and summer, I have been finding the occasional carpet beetle on my walls. Mostly, I have killed the larvae, observed and photographed the adults (and blogged them), killed the survivors. (I check behind the laundry basket for larvae daily.) After all, I don't want larvae in my sweaters and books.

But I had questions; how do the adults get here? How do they survive; what are they living on? How long do they live, and where, when it's freezing outside? How often do they breed? How long do the larvae live in our closets before they pupate; where are those pupae, and what do they look like? How long are they in this stage?

Most of the books and websites I found were focussed on discussions of control methods; how to eradicate carpet beetle larvae from your home and lab. Information about life cycle, especially the adult stage, was scant and brief.

Carpet beetle, in the wild.

When, with the advent of warmer weather, carpet beetle adults started showing up here more regularly, I found a glass container with a good lid (an old butter dish), and started keeping them alive on my desk.

"Pet" carpet beetles, on flower petals.

They live for at least a week with no food available. I give them a drop of water every couple of days. In a couple of websites, I read that they eat flower pollen. One named the flowers: daisies, asters, spirea.

Hmmm. The daisies and asters aren't out yet, and there are no spirea near my place; what have they been eating before they decided to pay me a visit? I've been treating them to the small flowers from my garden. They like maple flowers, dead nettle, apple blossoms; they seem to ignore violets and pansies. And they live longer than before.

They sleep often; sometimes I think one is dead. I have learned to mark its position. Hours later, when I check, it's "dead" somewhere else. They don't try to escape; their walls are glass, and they don't climb them. And their wings are used mostly for helping them flip back on their feet after they take a tumble. They don't try to fly out when I take off the lid to observe them. (Other beetles aren't so cooperative.) Awake, they trundle about, nibbling at the flowers, occasionally stopping to sip at a droplet of water.

Carpet beetle in captivity, on apple blossom stem.

How about breeding? They lay their eggs in sheltered locations; under baseboards, in crevices in the woodwork, and so on. I gave my "pets" an inch-square piece of coloured paper for a hiding place. That should provide the illusion of shelter and the eggs will stand out on the paper.

I can't tell which is male and which female, but once I had four or five live adults in the container, I figured there would be at least one couple. I kept a close watch on them, and caught a pair in the act:

Love in the springtime.

And there are eggs on the underside of the paper! In a couple of weeks they should be hatching. I'm planning the nursery already; a tightly-lidded, double-sealed container made cozy with old wool scraps. Maybe I should give them a stuffed Teddy bear.

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