Insect Survival In The Cold

We have definitely had a cold winter. It’s been colder than we are used to, anyway. At first, I was celebrating.” The cold will kill the bugs,” became my survival strategy. But the madman sure squashed that celebration. “A couple of cold nights will kill the plants in my greenhouse, but it won’t kill all your bugs.” Turns out he’s right: insect survival happens in spite of the cold.

Unfortunately, insects have evolved with cold temperatures. This isn’t the first time they faced cold weather. So, they have developed their own strategy to survive. Actually, they have several – all based on avoidance or acceptance.

Avoidance

Let’s talk about avoidance because that’s easier to understand. The easiest avoidance strategy is migration; head south with the birds. But there is a big difference with most insects. Because of relatively short life spans, insects who migrate don’t return – their offspring do.

We all know about the Monarch butterfly. Their migration habits are well documented. But the Monarchs aren’t alone in this avoidance technique. Other common butterflies such as the Painted Lady and Common Buckeye also fly south. As do the madman’s Skippers and a bunch of others. Some Hawkmoths, some Dragonflies and the Large Milkweed bug join the migrating hordes.

The reasons for flying south are specific to the species. For some, they fly thousands of miles to escape winter weather. Others look for a more hospitable environment for breeding. And some are just looking for more food.

Limited Mobility

Not all insects have the ability to travel far distances. For them, it’s much easier to just move into your warm house. Stink Bugs and Asian Lady Beetles are notorious for this. If you bring plants into your house for overwintering, be aware there may be hitchhikers. The madman has been known to move colonies of ants into the house hidden in the roots of plants.

Insects that live in colonies like Bees and Ants work together to protect each other, and especially the Queen. They huddle together, and this mass generates heat. Don’t worry about the ones on the edge because they are smart enough to keep changing places. Like birds, these insects sometimes shiver to generate more heat.

All Ages

Here it’s worth mentioning that not all insects are adults when cold weather hits. Beetles and Chaffers overwinter as larvae in the ground – we call them grubs. After their feeding frenzy of late summer, they burrow deep into the ground to overwinter as large grubs. As the ground warms, they will come close to the surface.

Underground isn’t the only place that harbors overwintering insects. Leaf litter, brush piles and even crevices in tree bark can protect insects, larvae and eggs. Many aquatic insects don’t have to work as hard as the beetle grubs. Their larvae can conduct business as usual under water unless thicker layers of ice begin to lower oxygen levels. If that happens, the larvae become inactive.

Accepting The Cold

Sometimes all the cover in the world can’t protect from extended freezing temperatures. Of course, bugs have a remedy for that. Some insects make it through the winter by entering a state of diapause. It is basically a period of suspended development during an insect’s life cycle. Although insects can go into diapause at any time, remember, we are talking about the winter season here.

Since Mother Nature likes to keep things complicated, different insects enter diapause at different stages of development. Some enter as eggs, some as larvae and others as adults. All you really need to know about this is that chemical changes occur within each insect that allows it to survive. Some insects reduce their water content to keep individual cells from freezing. Other insects actually manufacture an antifreeze to prevent cellular damage. The stage at which they enter diapause is genetically determined by species.

Just realize that when warm weather returns, the insects will be back. It’s interesting to note that most insects enter winter diapause as the days begin to shorten in the fall. But they don’t come out of diapause at the same time. Factors that trigger the end of diapause include length of day, temperature and available food and water. Each species has its own trigger. And each one comes out of diapause at a different growth stage. Remember, all the bugs in the area won’t appear on the same afternoon. We told you this was complicated.

Lots Of Bugs

I realize that we are using the terms “some” and “many” a lot but understand that there are around 2 million known species of insects in our world. The madman refuses to cover them all. And not all species are bad. Some prey on the bad bugs. Many pollinate our flowers, vegetables and fruits. They are essential to our survival. And I can’t imagine a world without the Monarch Butterfly. So, it’s not good to wish for winter kill.

Unless of course you are talking about ticks. But the madman says ticks are not insects; they are actually arachnids (8 legs, not 6), and they don’t enter diapause, so we never get a full winter without these things. They go dormant during cold snaps, but during a winter thaw they can be found out and about looking for their next meal.

Thinking of this gives me the heebie-jeebies. And the best remedy for that is hot cocoa.