Updated on September 19th, 2025
When the cold winds of winter arrive, we bundle up and turn on the heat. But what about insects? How do insects survive winter when they can’t regulate body temperature like we do? The answer lies in remarkable adaptations—from dormancy periods to natural antifreeze proteins—that let them outlast freezing conditions.
Understanding what happens to insects in the winter isn’t just fascinating science—it’s also practical. Many household pests don’t disappear; they slow down, hide in sheltered spots or pause development until spring.
These strategies are proof of insect resilience. While insects may seem fragile, their winter survival skills are finely tuned—and understanding them helps us better anticipate the pests we’ll face when warm weather returns.
Are insects cold-blooded?
Yes — insects are cold-blooded animals (ectotherms). That means they don’t generate their own heat the way we do. Instead, their bodies match the temperature around them. On warm days, they’re active; when the air cools, they slow down or slip into dormancy. It’s why summer feels alive with buzzing, while winter goes quiet.
For us, this explains why pests never truly disappear. Ants in the soil, moths in the closet, even flies tucked into wall voids — they’re simply waiting for spring to flip the switch back on. Understanding that insects are cold-blooded gives us a clearer picture of what happens to insects in the winter and why they always reappear when the weather changes.
How do insects survive winter?
Once the temperatures drop, cold-blooded insects need a plan. Some species migrate to warmer regions, but most stay put and rely on built-in survival strategies. Two of the most important are diapause and cryoprotectants.
What is diapause in insects?
Diapause is a kind of life-on-pause mode. Triggered by changes in day length or temperature, it halts growth, drops metabolic rates and lets insects wait out the season with minimal energy use. Unlike hibernation in mammals, diapause is deeper and more precisely timed—synchronized with the environment so insects re-emerge right when conditions improve.
Heat shock proteins – Molecular bodyguards
When insects enter diapause, the cold can wreak havoc on their bodies. Ice crystals forming inside cells act like tiny knives, cutting through delicate structures. Here’s where heat shock proteins (Hsps) step in. Acting like molecular bodyguards, they "chaperone" the cell's proteins, ensuring they don’t misfold or break apart when the cold strikes.
According to Insect Heat Shock Proteins During Stress and Diapause, insects boost Hsps during diapause, giving them the resilience to survive long freezes.
Nature’s antifreeze
For some insects, survival isn’t about shutting down — it’s about adjusting their chemistry. As winter approaches, they build up sugars like glycerol and trehalose, which act as natural antifreeze. These compounds lower the freezing point of their fluids and stop ice crystals from forming inside cells.
Think of it like a car radiator: antifreeze keeps liquid from turning solid in the cold, and these sugars do the same for insects — keeping their cells from turning into ice blocks.
According to Michigan State University Extension, these antifreeze compounds give insects a better shot at making it through long, harsh winters.
Examples of insects that survive winter cold
Some of the best lessons in cold survival come from insects themselves. These aren’t just textbook explanations of diapause or antifreeze — they’re real species showing how evolution has shaped survival in extreme conditions. Below are four examples of insects that survive winter, each with a unique strategy for making it through the cold.
European corn borer – Natural antifreeze at -40°F
The European corn borer (Ostrinia nubilalis) might look ordinary, but it’s a master of cold survival. As winter approaches, its larvae settle deep into corn stalks and switch to “low power mode,” cutting energy use and slowing development.
What sets it apart is just how far its antifreeze trick can go. European corn borers have been recorded surviving temperatures as low as -40°F — a feat made possible by the chemical defenses you read about earlier. By producing these compounds at high levels, the larvae stay alive through even the harshest northern winters.
According to Purdue Extension, the European corn borer’s ability to survive cold winters has helped it spread successfully in northern farming regions. It’s one of the clearest examples of how insects survive winter by leaning on biology instead of behavior.
Antarctic Midge – Diapause in Extreme Environments
The Antarctic midge (Eretmoptera murphyi) might be smaller than a pea, but it’s tough enough to survive one of the harshest places on Earth. Instead of fleeing the cold, its larvae hunker down in the soil and endure months of subzero temperatures — even surviving short stints trapped in ice.
According to a study in Frontiers in Physiology, larvae rely on true freeze tolerance, while eggs lean freeze-avoidant and adults are far less hardy. In simple terms: the larval stage carries the winter load, and each life stage uses a different tactic to make it through.
It’s a reminder that in Antarctica, even the smallest creatures have survival strategies that would be fatal challenges for almost anything else.
Arctic woolly bear moth – Frozen for 7 years
The Arctic woolly bear moth (Gynaephora groenlandica) looks ordinary at first glance, but it’s one of the most extreme survivors in the insect world. This caterpillar spends up to 90% of its life frozen solid, thawing for only a few weeks each summer to nibble plants before freezing again.
Its life cycle can stretch to seven years, one of the longest of any moth. Across that span, it’s active for just a handful of short summers. In the final year, it thaws long enough to transform into an adult, mate, and lay eggs — all in the space of a single week.
By stockpiling natural antifreeze molecules like glycerol, the woolly bear moth endures winter lows near -70°F.
Bumblebees – Why their winter survival matters
Bumblebees don’t vanish when the cold sets in — they bet everything on their queens. As winter arrives, worker bees die off and only young queens survive. These queens burrow into the soil or leaf litter, entering diapause until spring warmth wakes them.
According to USDA pollinator research, this cycle is fragile. Warmer winters and early springs can trick queens into emerging too soon, when flowers aren’t yet blooming. The result: fewer colonies take hold, and fewer pollinators are around when crops need them.
This matters far beyond the hive. Bumblebees are critical pollinators for apples, berries, tomatoes, and dozens of other crops. Their winter survival strategies directly affect the food on our tables
Bumblebees – Why their winter survival matters
Just as some insects have evolved incredible cold-weather adaptations, others—like bumblebees—face new dangers as the climate shifts.
When we think about climate change, we often picture melting ice caps or extreme weather events, but the consequences reach much deeper into the natural world—right down to the survival of insects essential for our food supply. Take the bumblebee—a vital pollinator responsible for the health of many plant species and agricultural crops. Already under threat from habitat destruction and pesticides, bumblebees now face another challenge: climate-induced shifts in seasonal timing.
In particular, queen bumblebees—who enter diapause to survive winter—are becoming confused by warming temperatures. Normally, they emerge from dormancy in spring to establish a new colony. But earlier springs and warmer winters are throwing off this natural cycle. Instead of waiting until spring, some hives are producing new queens too early, causing these young bees to attempt to found colonies before enough flowers are available to support them.
The result? The offspring struggle to find food in a landscape devoid of blooms and must endure temperatures for which they are not equipped. This leads to high mortality rates, which in turn means fewer pollinators for the next growing season.
And if you believe this only affects bees, think again. Bumblebees are prolific pollinators responsible for many of the foods we love. Picture the apple pie you enjoy, the guacamole on your taco or even your morning glass of orange juice. Without these buzzing workers, crops like apples, avocados, oranges and countless other fruits and nuts would suffer, leading to reduced availability and higher prices.
So, why should you care? The fate of bumblebees and other pollinators is intimately tied to the food we eat. When diapause timing goes wrong due to climate change, it’s not just the bees that suffer—we do too.
What happens to insects in the winter?
Climate change and insect winter survival
Insects may be small, but their survival strategies are nothing short of extraordinary. From entering diapause to producing natural antifreeze, these creatures have evolved remarkable ways to thrive in environments that would be fatal to most other organisms. Yet, as our world warms and seasonal patterns shift, these carefully tuned survival strategies are being disrupted—posing challenges not just for insects, but for entire ecosystems and the human food supply. The resilience of insects like the European corn borer, Antarctic midge and arctic woolly bear moth is a testament to nature's ingenuity, but it’s clear that the survival of these species, and many others, will increasingly depend on our efforts to combat climate change.
Notes:
But even these extraordinary adaptations aren't invincible. Climate change is throwing new hurdles at insects that depend on diapause.
Diapause may be one of nature’s most incredible survival mechanisms—and sound like the ultimate winter superpower—but even this remarkable adaptation is starting to feel the pressure. As global temperatures rise, insects that rely on diapause to outlast the cold face a challenge they never saw coming: autumns are getting warmer, and winters, while still cold, aren’t always getting cold enough.
Take Calliphora vicina, the common blowfly, for instance. Recent studies reveal a fascinating effect known as cross-generation plasticity, where the temperatures experienced by one generation can influence the cold tolerance of the next. When adult blowflies experience warmer autumns (around 68°F), their larvae end up less cold-hardy than those whose parents lived through cooler 59°F autumns. In other words, warmer falls produce offspring less resistant to freezing temperatures—an issue when winter bites.
This cross-generational inheritance of cold tolerance could spell trouble for ecosystems. If insects fail to properly enter diapause or lose their cold-hardiness, populations may struggle to survive harsh winters—leading to higher mortality rates. As a result, food chains and ecosystems could be thrown off balance.
The bigger issue? It’s not just about survival for these insects. Blowflies are just one of many species—literally and figuratively—feeling the heat. Monarch butterflies, silkworms, mosquitoes and the bean leaf beetle—to name a few—are part of at least 64 insect species that depend on diapause. When their timing or resilience goes awry, the delicate balance of food chains and nutrient cycles starts to unravel, with consequences rippling far beyond just one generation.
[Fascinating fact: Rootworms playing the long game]
Some Northern Corn Rootworm (Diabrotica barberi) populations have evolved a remarkable strategy to outsmart crop rotations by keeping their eggs dormant for up to four winters. This extended diapause allows them to emerge precisely when corn is planted, making traditional rotation strategies ineffective and presenting a challenge for farmers.
Some species, like silkworms, enter diapause as eggs, not only halting development but synchronizing their life cycle with the environment. This ensures that they hatch only when mulberry leaves—their primary food source—are available in the spring, making this a vital survival strategy during long winters.
On the other hand, insects like the flesh fly (Sarcophaga crassipalpis) undergo diapause during the pupal stage. This allows them to survive the cold with the help of stress proteins and metabolic adjustments, ensuring they emerge when conditions become favorable again.
