You might think there aren’t many reasons to look forward to winter (despite what your one friend with a snowmobile keeps trying to tell you). However, there is one great thing about the cold months: certain pests tend to disappear. It’s like magic! Suddenly, you can go on walks without being assaulted by hordes of hungry mosquitos! You don’t have to worry about ants getting at your food! Sure, all that winter snow removal gets a little old, but hey, there are no bugs!
…But maybe you’re suspicious. What’s the catch with this pest situation? Where did they go? What are they planning? Two things about that. One: we’re worried about you. We think winter’s got you a little paranoid. Take care of yourself this season. It’s going to be alright! Two: you’re right to be paranoid.
It’s true: although pests seem to disappear during the winter months, that doesn’t mean they can’t still find a way to be, well, pests. Here are the myriad ways that bugs we love, and some we don’t love so much, find to survive and thrive despite the cold and snow.
Insects that live on seasonal flora or crops need to find a warm place to eat. That’s why a lot of flying insects, such as certain kinds of butterflies, milkweed bugs, leafhoppers, beetles, locusts, moths, beetles, and dragonflies migrate north to south in the Winter, just like birds do. The fascinating thing about insect migration is that, in every case except for the monarch butterfly, the insects that move back north in the spring are not the same ones that went South in the winter. When insects with short life spans, like milkweed bugs and leafhoppers, migrate, they take their little winter vacation as an opportunity to copulate! Then, their offspring grows to maturity down south and flies back north in the winter. It’s a great deal for the little bug kids and a really bad deal for us.
The migration pattern of the monarch butterfly is particularly interesting to bug nerds like us. Unlike all other observed migrational insects, the same monarch butterflies that make the trip south also come back north in the spring. Not only do they fly over 2,500 miles to reach their southern vacation destinations, the same groups of monarchs always return to exactly the same place every year. Monarch groups pick one specific tree where they can hibernate, eat, and stay warm in peace, and come back year after year. Monarchs essentially have a winter home down south, just like your grandparents!
The monarch’s navigational method is so exact that scientists have been able to figure out where monarchs go every year very accurately. Monarchs that live west of the Rocky Mountains go to California in the winter, where they live along the Pacific coast near Santa Cruz and San Diego. Monarchs that live east of the Rockies go to the same 11 or 12 mountainous areas of Mexico and Michoacan.
We still don’t really understand how monarchs keep finding their way back to such specific locations. Even generations that have never been down south instinctively know where to go! Scientists believe monarchs use a combination of navigational aids such as a sensitivity to the Earth’s magnetic pull and the position of the sun to make their way. If you’re living down south in the winter and you see a monarch, consider yourself very lucky: it means they’ve chosen your home to be their yearly vacation destination.
Bug hibernation is called “diapause” and it doesn’t work exactly the same way as mammal hibernation does. When they start getting less daylight, a signal triggers in bugs to start putting on fat and dispelling water from their bodies. They also begin to avoid food and other material, such as dust particles and bacteria that could create ice crystals on or inside them. Then, the bugs seek out dry, covered shelters to spend the winter. These shelters can be manmade structures, such as chimneys, nooks in roofing, attics, basements, or even “bug hotels,” or they can be naturally occurring, such as nooks in trees, stumps, or caves. Once they’ve found shelter, some kinds of wintering bugs can replace the water they dispel with glycerol, which works like antifreeze.
During diapause, a bug’s metabolic rate drops to one-tenth of its usual activity, allowing the bug to enter “an inactive state of arrested development.” This state, along with the pre-winter preparation, allows bugs to simply wait out the winter in suspended animation. It’s basically like the cryo chambers in 2001: A Space Odyssey that place the crew of Discovery One in suspended animation while they’re en route to Jupiter. Only, you know, HAL 9000 doesn’t kill the bugs in order to ensure his mission is successful. Asian Lady Beetles are probably the most well-known example of insects who use this technique to survive winter, but wasps, honey bees, and the Mourning Cloak Butterfly also use different kinds of hibernation or diapause to make it through cold times.
Pupae and Eggs and Larvae, Oh My!
Sorry, we have to get a little gross here. One of the most common ways insects survive the coldest months is by timing their growth stages to make sure they have natural cover when they need it. Silkworms time their natural reproduction and growth cycles so they’re awkward gawky teens around winter time. When it starts to get really cold, they’re at the right age to transform into their pupae forms, which are equipped to continue to survive and grow even in winter.
If it wasn’t so nasty, you’d have to admit it’s pretty ingenious. Bugs that couldn’t normally survive winter temperatures create cocoons that shelter them, or enter a grub stage where they can burrow under the ground before it freezes. Some bugs even construct their own shelters out of twigs, leaves, and other natural litter, which they cling tightly to in order to maintain body heat. Some insects such as dragonflies, mayflies, and stoneflies can live under ice in winter waters as nymphs.
A lot of insects, such as the praying mantis, the corn rootworm, and some moths don’t “survive” winter at all, but instead time reproductive cycles so that during the coldest months, their eggs will have entered a “non-feeding” growth stage. At this stage of the egg’s development, all the resources required to grow and sustain the developing insect are self-contained, and the egg is thick and warm enough that the baby within can withstand the cold. This stage will last until Spring, when the egg will hatch. Eggs such as these are usually laid directly on food sources, like leaves, so that when the offspring emerges from the egg, they have a means to gather energy and heat right away. Again, ingenious. Also, gross. But hey, that’s nature.
They Come Hang Out at YOUR House!
To be fair, you probably saw this coming. We’re a pest control company, after all. You know we’re on that grind 24/7. Like we talked about earlier this month, a lot of bugs get pretty desperate to find a place to hide out over the winter. They’d like nothing more than to bunk up with you. They’re not great roommates, though: they’re messy, rude, gross, and they never pay rent. So, they’re basically like your college roommates. Watch out for Asian lady beetles, box elder bugs, and cluster flies, especially. These nasty boys are prone to enter homes and promptly fall asleep. Then, they’ll remain inactive until a warm day or the spring, when they’ll come out in force, in your house. That’s not great. Plus, bugs and other pests can get into your house through nooks, crannies, and cracks too small for you to even notice.
Once inside, they’ll tend to seek out secluded areas, especially if those areas are dark, humid, and provide easy access to food. Keep a close eye on your basement, attic, pantry, and closets. Finally, we’d be remiss not to say: if you do have a pest infestation, even in the dead of winter, Plunkett’s is here to help. Want to know more about pests’ uncomfortable relationship with winter and what it means for you? Check out some of our other blogs. If you want to set up an inspection or need a pest control expert, give us a call anytime. If you wanna geek out a little more about bugs and stuff, do either of those things!BACK TO BLOG