Bugs are all around us during summer and spring, but where do they go in the winter season? And if they die off, how do they come back every year? Let us learn the intriguing answer to this question
You might have noticed that while insects, butterflies, moths, spiders, and other creepy crawlies are abundantly present during summer and spring, but seem to vanish as soon as winter comes around.
Most arthropods are exothermic; they cannot produce their own body heat, so they are dependent on the temperature of their surroundings.
If the temperatures are too cold, they cannot move around. Moreover, some species simply do not survive cold winters and die away quickly as the weather turns chilly.
But the ones that do survive have found unique and interesting ways to survive the winter. In this article, we will talk about some of the survival strategies adopted by bugs in the winter.
How Insects Survive: A Brief Overview
There are three basic ways in which bugs save themselves when the icy chill turns on: Migration, Overwintering, and Hibernation.
|Overwintering||Larval stage: Most insectsNymph stage: Dragonflies, mayfliesEgg stage: Praying MantisPupa stage: Silkworm moths|
|Hibernation||Ladybird beetles and wasps|
Most butterflies spend their winters either as caterpillars or as pupa, and some overwinter in their self spun cocoon such as the swallowtail butterflies.
For the adult butterflies, the only option is to find a safe place like a crevice in a tree log or holes in trees.
Some butterflies might even spend the winter in places like attics and cellars, where they can find warmth.
The mourning cloak butterfly has evolved a unique mechanism that lets it remain warm and cozy in colder weather.
It has a compound similar to antifreeze in its blood, which helps prevent its innards from freezing over when the time comes.
It usually spends its time in this state, hiding away under rocks in the cracks between trees.
Perhaps the most winter survival strategy among arthropods is the migration of monarch butterflies.
Flying a massive 3,000 miles in one direction, Monarchs move from the northern United States to the warm and sunny SoCal and Mexico during winter. These magnificent flyers will travel as far as 100 miles a day.
They make the reverse journey back in the spring, coming back to enliven us with their beautiful colors. The whole journey takes them upwards of two months.
Adult monarchs feed on the milkweed plant, sucking nectar from its flower. During winter, their favorite food’s quality drops, and so does the length of the daytime during which they do their foraging.
The ones born just before the arrival of winter are born in reproductive diapause, a survival strategy that reduces their hormonal activity and helps them get ready for winter migration.
Before summer arrives, the monarchs come back and lay their eggs in North America.
Most moths adapt to one of the overwintering methods we described at the beginning, either doing this as larvae, pupae, or adults.
Isabell tiger moths
The Isabell tiger moths spend their winter in their larval stage, as the wooly bear caterpillar. They find small spaces, such as nooks and crevices, where they can survive the harsh cold.
These caterpillars have the unique ability to thaw and freeze many times over without any major damage to their internal organs.
Dark sword-grass moths
These moths also use the same strategy as monarchs in the winter. Their caterpillar form is known as the black cutworm, and it also migrates south.
However, the caterpillar does not have wings, so you might be wondering how they are able to travel such great distances.
The answer is simple: they use jet streams formed due to a southerly wind that blows during the winter.
When a cool, dry, and low-pressure center in the west meets a high-pressure system in the east, it creates a southward-bound stream of air.
These caterpillars hitch a ride on this jet stream and can quickly travel from states like Minnesota to Texas in under two days in this way.
Luna moths use a completely different way to spend the winter – they pupate and then hide under the hard shell of their outer skin.
They spin a cocoon around themselves and lie under leaf litter until the spring months come, and they can finally emerge as moths.
These moths also pupate, but they add an extra layer of security. As caterpillars, these little guys burrow a small nest for themselves under the ground.
When the time comes, they pupate inside and then emerge as moths during the summer and spring months.
Another curious case of winter activity is the springtails. These tiny little insects are also known as “snow fleas” because they are easy to recognize as black insects gathered on white snow.
Springtails are jumpers, just like fleas, but have no relation to them and are totally harmless to humans. They use a different mechanism for jumping – they have an abdominal appendage called the furculum that can wind up like a spring and propel them to (relatively) long distances.
Springtails can live in the harshest of circumstances. They have been found in the deepest caves on earth and also in the snowiest of weather. They live and breed throughout the year and are quick breeders.
Some species of these insects have a chemical called ethylene glycol in their bodies (it is basically the same thing as antifreeze) which allows their inner fluids to remain liquid even at very low temperatures.
We have all read the story of the grasshopper and the ants, and in a sense, they are not wrong. While ants may not hibernate, they do stock up for the winter.
They eat as much as they can (somewhat like polar bears), dig as deep as they can, and then huddle together to wait out the winter.
But within the species, there are several variations of this behavior.
Red Imported Fire Ant
The red imported fire ants tunnel deep underground and go as far away from the surface as possible to avoid the cold. Unfortunately, most of these ant nests do not survive the winter, despite their best efforts.
Below 41F, the Argentine ants simply cannot remain active. They have a unique place to nest in order to survive such harsh weather – they build their nests near loblolly pines.
These large trees have sunlight-absorbent barks that keep the temperature near the base of the tree warm enough to let the ants survive. They are able to look around for food even during the winter months.
Bees live in a strict hierarchy all their lives. Each bee nest has a queen, some workers, and some soldiers.
However, when the winter months come, queen bees produce a number of eggs that are destined to take up none of these roles.
This set of young bees will go on to become the queens of the next generation. Their only job is to survive the winter, along with the main queen of the nest.
Most of the other bees in the nest die off by the time winter arrives. But these new female would-be queens live on.
They find pollen to feed up and fatten out so that they can survive the winter without having to eat. They find nooks and corners under plant debris or in small burrows in the soil, where they can sleep.
These bees can also produce anti-freeze in their bodies, just like springtails. They use it to survive when the temperature drops below a certain point.
When the winter subsides and the time for summer is nigh, the would-be queens come out to make their own nests, start families and create a thriving colony once again.
We mentioned dragonflies and mayflies in the beginning. Astonished as you might be with this fact, these creatures are actually aquatic and not ground ones.
These flies spend most of their lives in water as wingless nymphs (eggs in some cases). They find a good spot in a pond or other water body where the temperature does not go as low as its surrounding.
Many of these insects have a lot of tolerance towards cold temperatures, just as long as it is not a sudden change. Fortunately, the temperature of the water is quite stable and does not drop suddenly, unlike the ground.
Most ticks do not die in the winter, despite popular opinion. Studies indicate that less than 20% of ticks die in the winter and that too when the temperatures fall below 0F.
It is true that most ticks go dormant when the temperature falls, but that does not mean that they cannot become active once again if it is a warm sunny day.
Some species, such as s the black-legged ticks, need to feed even during the winter, especially the females. They need their blood meals in order to lay eggs.
On the other hand, the Lone star tick and the American Dog tick become inactive during winter and do not come out of hiding till summer.
Ticks also adopt various strategies to ward off the cold winter. They may seek to hibernate or else reduce their activity levels very severely. They do this in order to reduce the expenditure of water from their bodies.
Ticks also gather glycerol around themselves to keep their insides from freezing when temperatures go below freezing point.
Just like other insects and arthropods, ticks react to the severity of the weather outside. In fact, they prefer to live in places where the temperatures stay high all through the year.
Most people believe that there is no need to check for ticks after a trip during the winter months, but that’s entirely wrong.
Since these tiny bugs can become active the moment the weather improves even slightly, it is best to check yourself thoroughly after every trip out in nature.
Ticks are carriers of many deadly diseases, such as Lyme disease and Rocky Mountain spotted fever, so it is best to always check for their presence.
Flies and Ladybugs
During winter, you will often find some bugs, such as stink bugs, ladybugs, and some types of spiders, inside your house.
These insects like the warmth in your home and tend to crawl in through any available crack or crevice.
The best way to avoid these pests is to use caulk and close up every little crack in your windows and doors. This also helps to improve the heating efficiency of your HVAC.
Once inside, many of these bugs enter into a diapause stage and find a corner to go into hibernation. They remain there and wait for the warm and sunny days to come back so that they can go outside and live their lives again.
Cockroaches have a reputation for being one of the hardiest insects in the world, and most of them can survive freezing temperatures upto 15F.
But what they are exceptionally well at doing is finding warmer places when the winter gets brutally cold. And one of the easiest targets is your home.
These roaches will find any crevice or dark corners, such as your crawl space or basement, to stay safely ensconced as the winter passes them by.
There are a few roaches, like the Yamato cockroach, who can do even more – these Japanese cockroaches can survive even below 15F temperatures.
Cockroaches can also lower their metabolism to meet the cold challenge, which means they will produce babies far slower in the winter (which is why you don’t see so many in those months).
For humans, it is easier to get rid of cockroaches in the winter month precisely because they get together in a few chosen spots and stay hidden there – for a professional, its pretty easy to find where these bugs are hiding in your house.
Spiders are another one of those species who love to inhibit dark corners of human homes to live out the winter season. They will make their homes in attics and cellars and weave rich webs for themselves in these spaces.
Many spiders, like the black widow, can overwinter as adults, and some, such as the brown recluse spiders, become inactive at very low temps.
Most spiders can sense that winter is coming and start their preparations early. They start finding spaces to lay their eggs (such as under trees and rocks).
Their activity levels reduce drastically during the winters, and many of them leave behind their egg sacs in these places and simply die.
During winters, the prey that these spiders feed on are also few and far between, so it is hard for them to survive.
Spiders like the tarantulas, which have a longer life, will hibernate and wake up in the summer. They have the ability to produce anti-freeze in their bodies like some of the other bugs we have talked about so far.
For the spider eggs, it is easy when they hatch in the spring. But some spider eggs also hatch in the winter, in which case all the babies huddle together in the sac to use their body heat to survive the winter.
Winters are the easiest times of the year to get rid of spiders from your home. All you need is to vacuum regularly and put some insecticide in carefully chosen places around the house.
You can essentially divide wasps into two categories – the solitary ones and the social ones. Solitary wasps usually dig their nest either underground or in cracks and crevices of rock and dead wood and in places like window frames, etc.
Most solitary wasps do not survive the winter. But they provision their nests with live insects (which they have paralyzed with their sting). They lay their eggs on these insects, and when the egg hatches and becomes a larva, it eats these insects.
Social wasps, who live in nesting colonies, behave more like bees. The queen wasps from these nests will mate and produce some females specifically for the purpose of becoming future queen wasps.
The queens will then go to hibernate in a semi-dormant state in places like attics, barns, sheds, and basements.
During the winter, if some of the queen wasps wake up, they might possibly die of hunger because they won’t be able to find the flowers to get nectar.
In the summer, these queen wasps awaken and start creating a new nest, raising the first worker wasps and slowly growing their nest over time.
Fleas become less active during the winter, but these insects are still around and can infect both you and your pets. In fact, infesting a pet that may have heavy fur on it would give them a good way to stay warm.
Female fleas lay eggs on such pets and hosts and can quickly raise as many as fifty nymphs in a day. Their survival strategy is just to find a host.
We have been saving the best for last.
The winter survival skills of mosquitos are really very diverse. There are species that can diapause, others who can stay as adults during winter, a few others who die off and leave their eggs behind, and some that hibernate like bears.
Male mosquitos usually die off. They neither have the capacity to hibernate nor the anti-freeze-like chemical in their bodies to keep them safe.
Females of the Culiseta, Culex, and Anopheles genera (the ones who spread malaria) go into a diapause state.
Their bodies reduce blood circulation and enhance fat reserves in order to survive the winter.
Moreover, they change their main food source – instead of going for blood, they start sucking on carb-rich food like nectar so that they can carry it through the winter.
Some of them can even carry eggs all through the winter!
In such a state, they also look for areas with plenty of moisture where they can hide. These could be places like storm drains, burrows, and so on.
Some mosquitoes look for trees, stems, exposed plant roots, etc. which have small burrows in them to survive the winter.
There are a few species that can brave out the winter without doing anything. These are called snow mosquitos.
Lastly, the tale of the pitcher plant mosquito is one that deserves special mention. This mosquito lets itself get frozen inside the ice, which is stored in pitcher plant leaves.
Bugs have survived millennia and evolved with their own ways of coping with the winter, harsh as it may be.
While some of them find spots to hide and brave out the winter, others can survive by going into diapause. A few die, leaving behind their eggs to brave the winter and emerge the next season.
Each arthropod has a unique lifecycle and a different way of surviving. But one thing is for sure – they all find a way to live on for the next season.
Thank you for reading!
Some of the hardiest winter survivors are the springtails, also known as snow fleas. Below are a few reader emails enquiring about how they survive in the winter.
Letter 1 – Snow Fleas
Thanks for posting the pictures and letters on Spring Tails. Similar to one of your readers we saw these little guys on Christmas day in Oregon and have been stumped for a month trying to determine what they are. Here are two more pictures we took that you can publish. The Douglas fir needle gives you a little bit of scale.
We are glad to hear our site assisted you in the identification of your Snow Fleas, a type of Springtail that can be very plentiful on warm winter days.
Letter 2 – Snow Fleas
Help! Thousands of Tiny Purple Bugs!
We live in Oregon and have recently been invaded by literally thousands of these tiny what look like purple bugs. They seem to cluster together in piles, mostly hiding out of the rain, but sometimes in the puddles themselves. At this point only outside. Here are a few photos. Any ideas? Any help would be appreciated. It’s quite the mystery. Thanks,
These are most certainly a type of Springtail known in the singular as a Snow Flea. These minute dark blue flea-like insects form large aggregations in the winter months and are sometimes found on the surface of snow on warm days. They are found in leaf litter and holes in the soil and are believed to feed on pollen.
Letter 3 – Springtails: Snow Fleas
piles of tiny insects in my driveway
What are these things???
There are several piles of millions of tiny moving insects in several places in my driveway. They are a dark grayish, brownish color. They are oblong and have visible antennae. At first, I thought they were piles of dirt.until I noticed they were moving. I can’t find anything on the Web. Help! Thanks,
Springtails in the order Collembola, are minute insects often found in large numbers. These are probably Snow Fleas, Achorutes nivicola, a type of Springtail that is found in the winter, often on top of the snow on warm sunny days.