My parents live in a 100-odd year old farmhouse out in the country west of Toronto. Sharing the building with wildlife was part of growing up, whether it was bugs or vertebrates. We had mice in the walls (occasionally seen scurrying across the kitchen floor), starlings in the eaves, snakes and newts in the unfinished basement, squirrels and bats in the attic. Most of our houseguests were primarily active during the spring and summer months. In the winter, our primary visitors were, and are, ladybugs.
Anyone in an older home is probably familiar with the mid-winter ladybug invasions that seem to coincide with warm spells. Within the space of a few days, the house seems to become overrun with them. They gather in the corners of window frames, congregate around light fixtures, and seem to find their way into or onto just about everything – hair, clothing… food… Just where do all these bugs come from, in the middle of winter when insect life, as a whole, is pretty absent?
Growing up I used to think that the warm spell encouraged a hatch of ladybug eggs that had been laid in the fall before the first frosts. Actually, all of these uninvited guests are adults, that crawled under the siding or into the cracks of the house in the fall to overwinter. In the warm spell, they awaken and start to move around, and the warmer temperatures indoors draw them inside through small cracks in the walls or around the windows. I know that in my parents’ 100-year-old farmhouse, the insulation is not quite up to modern-day standards, and there are ample opportunities for a little beetle to squeeze in to the much more habitable warmth of the indoors.
The ladybug most people are familiar with is the Multicolored Asian Lady Beetle, an extremely variable ladybug that comes in a wide range of colours and spottiness. Above you can see two very different colour variations of the same species. It’s also the primary culprit in winter home invasions. The species was introduced in Louisiana and Mississippi in 1979 and 1980, as a method of controlling aphids and other agricultural and horticultural pests. They’ve spread a long way since then! You can actually buy ladybugs commercially from garden centres or online to release in your garden as a natural pest-control method.
Ladybugs in and of themselves are essentially harmless, although they can be a bit of a nuisance during their winter invasions. Once the temperature drops following the warm spell, ladybugs that have come into your home will congregate in corners where they will resume their hibernation. During the winter they live off stored fat reserves, but the dry air in most homes during the winter can cause dehydration in these little bugs that results in piles of dead bodies. Ladybugs that manage to make it into enclosed light fixtures usually can’t make it out again and collect in the bottom.
Aside from this, the ladybugs leave little stains that, growing up, I took to be “ladybug poop” in the corners where they congregate. In actuality, these stains are the result of the ladybugs being startled, threatened or stressed. As a defense mechanism, ladybugs have the ability to excrete some of their “blood”, which has a bright yellow colour and rather sharp, and not altogether pleasant, smell, which discourages potential predators. In prepping the windowframes of my parents’ house for repainting this winter I could easily tell where the ladybugs had been.
I was rather surprised that our recent warm spell didn’t cause the sort of mass invasion I tend to expect with higher temperatures, and while I came across little groups of ones or twos in most corners of the house, there weren’t the large groups I associate with mid-winter warming. Something yet to look forward to, I guess!