Each winter we have a pause in the insect community. No more aphids, Japanese beetles or squash bugs. It also means no praying mantids, Luna moths or katydids. How do they survive freezing temperatures, snow and cold? It isn't like they have a cozy house with central heat and air to ride out the winter, so what do they do?
There are a number of ways insects prepare for a long, cold spell and it depends on the species as to how they go about this. The only thing they have in common is the term, diapause. The insect literally hits the 'snooze button' and goes into a state of suspended animation to wait out the cold weather. The insect reduces its metabolism to about one tenth its normal state and finds a safe place to wait for warmer weather. Many of them also convert some of their bodily fluids to alcohol which prevents freezing and cell damage in temperatures well below freezing. That is how insects in the far north never seem to have their populations dwindle. There are just as many mosquitoes and blackflies on the tundra each spring as there were the previous year.
How do insects know when to hibernate? There are many cold snaps in the autumn and there is always an Indian Summer when it warms up again. How do they know when it is the real thing? Daylight hours is the key. When the sun slides south on its winter journey and days get shorter, insects know when to button up and wait for spring.
Depending on the type of insect, the way they take to wait out the winter can take several forms. Some simply lay eggs and the new generation hatches out when spring arrives. How do they know that? Usually insect eggs have a specific incubation period and that coincides with how long a winter usually lasts. The adults simply lay eggs and die. Other insects overwinter as grubs or larvae. Our garden nemesis the Japanese beetle overwinters as a grub.This 'in between' form usually finds shelter underground or inside fallen logs or under rocks, their internal antifreeze keeping them from harm until spring arrives. Other insects overwinter as adults. We're all familiar with a number of them. Asian ladybeetles and stinkbugs are a couple of the most common ones we encounter. They tend to seek winter accommodations inside our homes and plague us with their unwelcome numbers. Aphids and leafhoppers overwinter as adults as well. They find cracks in tree bark and fallen logs.
Mosquitoes are a summer problem in most areas and we all long for the cold day that they all die. But do they? There always seems to be an overabundance of mosquitoes each year, no matter how cold it gets. So what gives? Some species of mosquitoes simply lay eggs in the water and die. The eggs' internal antifreeze keeps them safe until weather warms again and they hatch into larvae. Some species overwinter as larvae with the diapause waking them when the sun shines for more hours and the temperatures moderate. Still other species overwinter as adults, taking shelter in abandoned barns, stables or inside dead trees and cracked fenceposts. Like it or not, mosquitoes are adaptable and will be with us forever. They may even outlast humans.
Honeybees prepare for the winter by purging the colony of all non-essential residents. If the bee isn't necessary to the survival of the colony, it is just another mouth to feed. The drones are kicked out and the nursery where eggs are laid for new bees is reduced. The population that is left, the workers and the queen huddle together in a ball with the queen at the center. The ball of bees rotates with each worker spending time in the warmer core and on the outside edges, that way, everyone gets an even shot at surviving.
Spiders also have different ways of overwintering. Most often, the adult spider lays eggs in the fall and they either wait to hatch until spring or once they do hatch, the baby spiderlings huddle together in the egg sac until spring arrives. Many will die, but enough make it through to create the next generation. Outdoor spiders also tend to overwinter under the snow. It acts as an insulating blanket and the spider can survive in a semi-dormant state until the spring thaw and warmer weather. House spiders go about their business in attics and basements regardless of the weather, so they aren't affected much by the seasons.
Many beetles overwinter as adults. The Colorado Potato beetle simply digs a deep burrow in the agricultural field and hibernates with the slower metabolism and the antifreeze that its body produces. They purge their bodies of food and waste before doing so because those substances can freeze and harm the insect. Many other beetles follow a similar pattern.
Our insect population has adapted to every condition that climate can throw at it and there are very few places on Earth where there aren't any. Winter is not the end and no matter how many times you hear that a cold winter will kill the insects, it just isn't true. There may be some that don't prepare properly or choose a safe shelter, but the vast majority of these creatures will survive and thrive the next season.