Wasps in cold climates don’t fly south. The colony you watched all summer dies out by winter, and only a small number of young queens survive the cold by hiding and staying still until spring. Every new nest you see next year is started from scratch by one of those survivors, not by the old colony returning.
Who Dies and Who Survives When Winter Comes
A yellowjacket or paper wasp colony in a temperate region normally lives for one season only.1Nature. Viral load, not food availability or temperature, predicts colony longevity in an invasive eusocial wasp with plastic life history Winter cuts off food and foraging, so these wasps put everything into one round of raising new queens before the cold arrives. At the end of summer the colony produces young queens and males, and the males mate with the queens.2Annals of the Entomological Society of America. The Behavior of Hibernating Polistes Wasps. As the cold sets in, the workers, the males and the old founding queen die, while the mated young queens leave to find shelter.3Annals of the Entomological Society of America. The Behavior of Hibernating Polistes Wasps. The few survivors stay local, often within the same yard or building.
Workers are females that don’t reproduce; they hunt, feed the young and build the nest. Young queens look much like workers but are often a bit larger, and in autumn they leave the nest instead of staying to work. The young queens don’t return to the old nest, so every nest is a fresh start.
In early autumn the nest may still look busy, but fewer workers come and go as the colony weakens. The dead or sluggish wasps on windowsills and the ground are mostly workers and males at the end of their natural life, not victims of one cold night. The young queens leave quietly, one at a time, so they are rarely noticed.
The details differ among species, so timing and hiding spots vary a little from one kind to another.4Annals of the Entomological Society of America. The Behavior of Hibernating Polistes Wasps.5Annals of the Entomological Society of America. The Behavior of Hibernating Polistes Wasps.
How Queens Make It Through Winter
Before sheltering, a young queen feeds up on sugary food such as nectar and fruit juices, building the body reserves she will live on. After mating she leaves the nest on her own and looks for a protected spot instead of staying with her sisters.
Overwintering queens hide in protected nooks and crannies.6Annals of the Entomological Society of America. The Behavior of Hibernating Polistes Wasps. They don’t seem to hunt for warmer places; the shelter mainly keeps off rain, hail, snow and predators.7PubMed Central. The Impact of Climate on the Energetics of Overwintering Paper Wasp Gynes (Polistes dominula and Polistes gallicus) So they end up under bark, in log piles, sheds, wall gaps and attics.
During winter a queen stays in a slowed-down resting state where she doesn’t feed or fly. She grips a surface or tucks into a crack and waits. Cold itself isn’t the main danger; wet and predators are. She wakes when spring warmth returns.
All of this runs on reserves she built up in autumn, mostly fat.8PubMed Central. The costs of overwintering in paper wasps (Polistes dominula and Polistes gallicus): the use of energy stores These stores are small, but a resting paper wasp queen uses only about 2 to 2.6 joules of energy a day, a tiny amount.9PubMed Central. The costs of overwintering in paper wasps (Polistes dominula and Polistes gallicus): the use of energy stores By spring her fat is usually still sufficient, but her sugar stores are nearly used up.10PubMed Central. The costs of overwintering in paper wasps (Polistes dominula and Polistes gallicus): the use of energy stores That means she needs to find sugary food like flower nectar soon after waking.
Disturbing a queen can kill her: waking burns energy faster than resting, and a queen roused early in a warm room may have nothing to eat. A mild spell in winter carries the same risk. A queen in a protected, steadily cool spot tends to do better than one in a spot that warms and cools often.
Why Wasps Get Pushy in Late Summer
Through summer, workers hunt insects to feed the larvae and get a sugary drop from the larvae in return.11Wasps Removal. Why Are Wasps Aggressive in September? Workers can’t digest that protein themselves, so the larvae’s sugar is their main food.12Wasps Removal. Why Are Wasps Aggressive in September? By late August or early September the queen stops laying and the last larvae finish growing.13Wasps Removal. Why Are Wasps Aggressive in September? Thousands of workers lose their sugar source and go looking for jam, fruit, soda and beer.14Wasps Removal. Why Are Wasps Aggressive in September? The wasp at your picnic is hungry, not defending anything.15Wasps Removal. Why Are Wasps Aggressive in September? Earlier in summer these same workers were busy hunting insects and caterpillars, so they showed little interest in your food, apart from the odd protein snack such as meat at a barbecue.
A wasp feeding at your drink away from its nest isn’t guarding it, so it usually leaves you alone if you stay still. Stings are more likely when a wasp is trapped, squeezed or swatted, for example one hiding in a can or cup. Checking a drink before you sip, especially from an open can or bottle outdoors, avoids swallowing one by accident.
To keep them away, cover drinks and use cups with lids or straws. Pick up fallen fruit under trees, keep bins sealed and rinse sweet containers. If one lands on you, stay calm and avoid swatting.
The problem peaks as colonies wind down in late summer and early autumn, and the first hard frosts end it as the workers die. Removing a nest now often isn’t needed, since it will soon empty. A nest close to doors or play areas may still be worth removing safely.
Does the Old Nest Come Back to Life
Even in yellowjacket populations known for long-lived colonies, few survive winter: of 76 colonies followed in one region, only one made it into a second season.16PubMed Central. Viral load, not food availability or temperature, predicts colony longevity in an invasive eusocial wasp with plastic life history None of 41 colonies found the next year lasted through the winter.17PubMed Central. Viral load, not food availability or temperature, predicts colony longevity in an invasive eusocial wasp with plastic life history A nest you saw last summer is almost certainly empty now.
Most social wasp nests are built for one season and are not repaired or reoccupied. A young queen starts her own nest from scratch, often well away from where she was born, and the old nest is simply left behind to break down over winter. Paper nests left in sheltered spots like attics can last a long time, but they hold no living colony. Nests in the open, such as on branches, may fall apart in rain and wind. Underground yellowjacket nests collapse and become part of the soil, leaving only a small hole or dip.
There are exceptions. European paper wasp queens sometimes reuse old nests in spring, likely saving energy and time, though old nests may also carry more disease.18Redia. Reuse of old nests by the European paper wasp Polistes dominula (Hymenoptera Vespidae) And in warm tropical and subtropical places, some yellowjacket colonies keep several queens and survive for years.19Georgia Southern Commons. High rates of polygyny in tropical Mexico within the native range of Vespula squamosa These multi-year colonies can grow far larger than the usual one-season nests.20Nature. Viral load, not food availability or temperature, predicts colony longevity in an invasive eusocial wasp with plastic life history This is rare in their native cooler ranges.21Georgia Southern Commons. High rates of polygyny in tropical Mexico within the native range of Vespula squamosa
A new nest in the same spot next year doesn’t mean the old one came back. Good sites, like a sheltered eave, attract new queens year after year.
An empty nest can be removed safely in winter once it’s quiet, but check first for activity on a mild day. Taking old paper nests down from eaves can discourage reuse by paper wasps. In warm regions, large nests can still be active in winter, so call a professional there.
How Mud Daubers and Other Solitary Wasps Survive
A mud dauber is a solitary wasp that builds tube-like nests of mud, often under eaves. Mud daubers may raise two generations in a summer, but no adults survive the winter.22sun-courier.com. Conservation-Mud Daubers – wasps I can live with The young spend winter in a resting stage between larva and adult, inside the mud nest.23sun-courier.com. Conservation-Mud Daubers – wasps I can live with They finish changing into adults and come out in late spring.24The Center for Northern Woodlands Education. Mud Dauber Wasps
A female builds mud tubes or cells and stocks each with paralyzed spiders as food for her young. She lays an egg in each cell and seals it with mud, then leaves the young to develop alone. The young eat the spiders, grow, and then pupate within the sealed cell.
Unlike young in a social colony, which adults feed all summer, her young don’t need her after the cell is sealed, so her death in autumn changes nothing for them.
For your house, this means a mud nest in winter may hold living young, and knocking it down removes next spring’s wasps. Mud daubers rarely sting people, and many people leave them alone since they hunt spiders.
Mud nests are hard, gray-brown tubes or lumps, while paper nests look papery and gray. In cold climates, paper nests are empty in winter; mud nests may not be.
Why You Find Wasps Indoors in Winter
Heating warms the sheltered spots queens choose, such as attics, wall gaps and window frames, and can rouse a queen weeks early. She wanders toward light and windows, often slow and clumsy. With almost no sugar left and no flowers outside, she usually dies soon.25PubMed Central. The costs of overwintering in paper wasps (Polistes dominula and Polistes gallicus): the use of energy stores
A wasp indoors in winter is normally a queen that overwintered in your house. A nest is not active inside in winter, and one would be unusual in a cold climate because the colony has died. Seeing one or two is typical and mostly not a cause for alarm.
To handle one, trap it under a glass with a card slid beneath and put it outside or dispose of it. Don’t squash it against a surface, since even a sluggish wasp can sting if pressed, and don’t spray the wall or attic with insecticide for a single wasp. Moving it outdoors on a warm day won’t save a queen woken too early, but it is a harmless choice if you prefer not to kill it.
Sealing gaps around windows, vents and eaves in autumn keeps queens out. Several wasps repeatedly in one room may point to an entry route worth checking.
When Wasps Come Back in Spring
Wasps and bees that overwinter emerge earlier when spring temperatures are warmer, and those from warmer places tend to emerge earliest.26Functional Ecology. Climatic origin and plasticity shape emergence timing and fitness in bees and wasps under experimental climate regimes But warm late winters cost them more body weight, especially wasps from cooler areas.27Functional Ecology. Climatic origin and plasticity shape emergence timing and fitness in bees and wasps under experimental climate regimes An unusually warm spell can leave them weaker when food is still scarce.
Queens of different species wake at somewhat different times, so sightings don’t all come at once. A warm spell can bring a few out early, and a following cold snap can send them back into hiding. A lone wasp on a warm early day doesn’t mean summer has started.
The first big, slow wasps in spring are queens looking for nest spots. They visit flowers for nectar and inspect eaves, sheds and fences. The first small nest is a few cells built by the queen alone. Workers appear a few weeks later, and numbers climb through summer.
That makes early spring the best time to discourage nests. They are tiny and easiest to remove, so watch sheltered spots near doors. Knocking down a starter paper nest often makes the queen move on. Large summer nests are best left to a professional.