by Sarah Walker, from the April 2005 Newsletter

Ladybugs have been shacking up in my house all winter. They’re cute, they don’t make a mess, and I’m used to them. On sunny days I scoop them up and let them out.

I gathered some up in an Altoids tin and took them to the Barr Entomological Museum at University of Idaho where experts identified them as “Convergent” ladybugs, which is a very common native species. They were surprised because they were expecting the Asian Multicolored species (see photo).

Normally ladybugs sleep through winter in a type of hibernation called “diapause,” but in my heated house they climb the curtains, rendezvous on their favorite lampshade, or even hike to the bathroom. They may have come inside via firewood or a houseplant that I brought inside last fall. There are about a hundred of them.

According to Frank Merickel at the Barr Museum (worth a visit, by the way, you’ll see some neat stuff), ladybugs are big eaters. On the Palouse, their best source for aphids is the crop fields outside of town.

At the U of I Entomology Department, James “Ding” Johnson explained the short life of the Convergent ladybug to me. The most basic thing about them is exactly what we learned in the nursery rhyme: at certain times, they just want to fly away.

Let’s start in summer when it’s hot and dry and the green leafy plants and crops start to dry up. The aphids that lived on the sap in this spring greenery start to die off. These protein-rich aphids are what ladybugs and their larvae have depended on while they lay eggs and start new generations. When our landscape turns from green to gold, some ladybugs visit our watered yards. They need to fatten up for winter, so they switch to eating pollen. This is when they start finding each other and flying around like crazy—even, as my neighbor reports, flying right into people!

“Flying away” isn’t easy for ladybugs because they are actually poor fliers. Like all beetles, their forewings are hardened to function as wing covers. In flight, the brightly spotted covers, called elytra (el-EYE-truh), stick out stiffly to the sides, and the two membranous hind wings do all the work.

Yet ladybugs often travel hundreds of miles, and they do so by using the winds. In fall, rising thermals and westerly wind patterns take many of them up to Moscow Mountain or beyond where they cluster in sheltered ravines, protected in rock crevices or under bark (or, they may spend winter under your deck). At either location, they stay together all winter, fattened on pollen and needing neither food nor drink. Convergent ladybug clusters can be huge, from hundreds to millions of beetles.

It turns out that clustering for winter is an advantage if you are little and stinky like ladybugs are. A winter aggregation would make a tasty meal for mice or birds if ladybugs didn’t ooze out a bitter liquid when pestered. A predator only has to try a few of the fat sleepy ladybugs with the “danger-don’t touch me” red and black markings before it learns to leave the rest of them alone.

In spring the ladybugs become active. They start mating and leave the mountains, riding the winds down to lower elevations where aphids are sucking up the sap flowing through leaves of crop plants. In spring, ladybugs start families, attaching little cream-colored eggs by their pointy ends to the bottom of leaves. The larvae that hatch after 4—7 days eat so many aphids that they outgrow their skins, not once but several times (each molt is called an “instar”). The larvae consume more aphids than the adults. After 14—21 days as a larva, ladybugs spend 4—7 days enclosed in a pupa attached under a plant, hidden and sedentary while their worm-like bodies transform into an insect with wings, ready to start hunting for soft-bodied prey like scale insects, mealy bugs—and aphids.

Note: the aphids that we choke on in fall are the late-developing “Smoky-wing ash aphids.” During early summer when ladybugs feed, these aphids are underground feeding on tree roots, not available for ladybugs.

Copyright: Copyright on articles, recipes and images are jointly held by the Moscow Food Co-op and the respective contributors, except were otherwise noted.

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