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Sheep Dog Hollow: an eco-friendly renovation

Ladybug invasion

One homeowner finds that a winter ladybug invasion isn't so bad.

By Carrie LeberGuest blogger / March 10, 2010

Multicolored Asian lady beetles (Harmonia axyridis) clustered together for hibernation. These ladybugs were first imported to the United States as a predator of aphids but often invade houses for the winter.



Maybe it’s a harbinger of bad insulation – or, on a more optimistic note, perhaps a sign of good fortune and an early spring – but my overwintering crop of ladybugs is waking up and beating at the windows to get out.

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My first fall in Connecticut a few years back, the ladybugs in my garden (or ladybirds as some want to call them) slyly tucked into cracks and crevices in the façade of my house, over time making their way into the gentler temperatures indoors.

I recall a courageous few blowing in with the opening of a door, or flying purposefully through an open window. Eventually I’d find ladybugs stowed away over the winter months tucked behind curtains and into window jams.

It’s important to note that ladybugs are not structure-damaging pests – if touched or terrified, they can leave small stains as part of a defense reaction known as "reflex bleeding," which is intended to prevent predators from eating them. But they don’t enjoy meals of wood or fabric as other insects do – and I’ve never suffered a bite, although there some experts who swear they can land a well placed nip or two.

As a San Francisco Bay Area native, harboring ladybugs (rather willingly or unknowingly) inside the home is something I really hadn’t seen before. They manage to survive horrendous weather conditions by finding a reasonable place to hide and then falling into a state of “diapause” – in which their metabolism lowers and simultaneously, their freezing points, as they drop into dormancy or bug hibernation.

This is the reason ladybugs are often stored in refrigerators at garden centers where they rest until released into a deliciously aphid-laden garden. Ladybugs hiding in corners and crevices holding perfectly still may well be alive.

In older homes, hoards of ladybugs may be found in attics during the colder months – happily hunkered down in a quiet corner for a long winter’s nap. As insulation and better building practices advance, the tiny crevices and shrunken wood around windows that ladybugs rely on to gain entry into homes are getting harder to find.

My home has new windows and paint – making insect entry inside quite a project.

But well-sealed windows and doors notwithstanding, this past winter my ladybugs must have collectively realized they’ve found in me an agreeable host. I do tend to open windows quite a bit in the fall – hoping to catch some last gasps of fresh air before winter heating turns the house into a tightly sealed but somewhat stagnant micro environment. So in they come.

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