Winter is a time to cuddle up inside, whip up a cup of cocoa, and enjoy the comforts of a warm home. We do everything we can to make sure our pets and animals are comfortable as well – if you’re cold, they’re cold, right?
But what about insects? Each spring, insects seem to reappear out of nowhere. Where do insects go for the winter?
How do insects survive the cold?
In short, it depends on the insect and the severity of the weather, but there is a reason insects have been around for so long. They are really good at surviving less-than-ideal conditions and adapting as more fit individuals. Some insects will die, while others in milder climates will spend it hunkered down in a harborage area.
While hunkered down, most insects will slow their metabolism to conserve resources and this can be done in two ways: torpor and diapause.
Most insects are only active during the day (diurnal) or at night (nocturnal). When they aren’t active, they are in a state of rest called torpor. This “sleep” isn’t as deep as a hibernation, but more like human rest in that it only takes a slight stimulus (light, noise, etc.) to wake them.
Alternatively, diapause is a period of suspended development in the insect, usually due to unfavorable environmental conditions. Diapause would be the insect equivalent of a bear going into hibernation.
Common pests and winter habits
Here is a closer look at a few common pests and how they spend their winter days:
Mosquitoes are often the first to get noticed upon their return in the spring season. They rely on a mixture of diapause and harborage in protected areas like tree holes and ground burrows. Mosquitoes will spend the winter as eggs, larvae, pupae, or adults.
In the aquatic immature (non-adult) stages, mosquitoes will gather in areas where water isn’t frozen and slightly warmer. Growth and metamorphosis will slow to almost nothing until temperatures warm up. As adults, mosquitoes rely on protected areas to weather the cold.
Cockroaches are one of the more bothersome insects for humans regardless of what time of year it is.
German cockroaches have grown accustomed to and perfected indoor living, so their winter habits are not surprising. German cockroaches will spend all their days indoors, close to a food source. Regardless of the temperature outside, a home or structure is usually a constant comfortable temperature and humidity, making it a perfect year-round residence for insects like German cockroaches.
American cockroaches prefer to live outdoors seeking winter harborage in wood or leaf piles but will seek warm harborage in damp quiet areas of a home if needed.
Flies typically overwinter as larvae or pupae buried in organic matter. As the ground warms in the spring, the increase in temperature signals to immature house flies that it is okay to resume development.
House flies are notorious for having a short life cycle, spending only around 2 weeks in the adult stage. However, during winter months, adult flies can take refuge indoors as a surprising indoor pest during winter.
Spiders survive winter differently based on region of the world and whether they typically frequent indoor or outdoor locations. Like cockroaches, some will use structures for protection through cold winter months, feeding on other insects that have sought indoor shelter as well.
Alternatively, some outdoor species will utilize the spider egg sac as protection; instead of hatching and leaving, spiderlings will hang out within the sac until warmer weather prevails.
Tips and tricks to prevent wintering pests
So, what do can we do with this information (besides sharing it at your next dinner party)? Much like everything else related to pest management, we use the knowledge of insect biology and behavior to aid us in their control.
Perimeter control is imperative to keeping insects from using your home as an area to overwinter. Fall months are a great time to not only wrap your plumbing fixtures, but check for areas of insect entry in weeps, around doors, and in soffits.
After sealing and implementing exclusion devices, plan to apply a fall insecticide treatment. Microencapsulated products will provide extended residual protection to the perimeter of the home as a chemical barrier.
Spring’s arrival is often noted by a break in the cold and slightly longer days. The spring season is the perfect time to begin applying insect growth regulators (IGR) outside. As we talked about earlier, flies and mosquitoes will be emerging from a long winter’s nap, often from immature stages into adulthood. By applying IGRs early in the spring, you are integrating a control tool ahead of an insect population boom.
Preparing for colder temperatures is more than cleaning the fireplace; it’s securing the perimeter of your home with exclusion and insecticides so that insects don’t choose your home to spend the winter.