Where Do Mosquitoes Spend the Winter?

Female mosquitoes hunker down

Where do mosquitoes go in winter?
Where do mosquitoes go in winter?. Susan Ellis, Bugwood.org (CC license)

The mosquito is nothing if not resilient. Based on fossil evidence, scientists say the current mosquito we have today is practically unchanged from 46 million years ago. That means it lived through the ice age of 2.5 million years ago—unscathed.

It stands to reason that a few months of winter hardly phases a cold-blooded mosquito. So, what happens to the mosquito during the winter?

The life span of a male mosquito is up to 10 days, and then it dies after mating.

The males never make it past the fall. The female mosquitoes spend the colder months inactive in protected places, such as hollow logs or animal burrows. It is fair to say the mosquito enters a period of dormancy, similar to a bear or squirrel hibernating for the winter. She can hibernate for up to six months.

Mosquito Eggs in the Fall

The first three stages—egg, larva, and pupa—are largely aquatic. In the fall, the female mosquito lays her eggs in areas where the ground is moist. Female mosquitoes can lay up to 300 eggs at a time. The eggs may lie dormant in the soil until spring. The eggs hatch when conditions become favorable again when temperatures begin to rise and sufficient rain falls.

These first three stages typically last 5 to 14 days, depending on the species and the ambient temperature, but there are important exceptions. Mosquitoes living in regions where some seasons are freezing or waterless spend part of the year in diapause; they delay their development, typically for months, and carry on with life only when there is enough water or warmth for their needs.

Larval and Pupal Stage

Certain mosquitoes can survive the winter in the larval and pupal stage. All mosquito larvae and pupae require water, even in winter. As the water temperature drops, the mosquito larvae enter a state of diapause, suspending further development and slowing metabolism. Development resumes when the water warms again.

Female Mosquitoes After Winter

When the warm weather returns, if the female mosquito hibernated and has eggs to deposit, the female must find a blood meal. The female needs the protein in blood to help her eggs develop. In the spring, when people reemerge outdoors wearing short sleeves, is exactly the time when newly awakened mosquitoes are out in full force looking for blood. Once a female mosquito has fed, she will rest for a couple of days and then lay her eggs in whatever standing water she can find. Under ideal conditions, females can live about six to eight weeks. Usually, females lay eggs every three days during their adulthood.

Places Mosquitoes Do Not Call Home

Mosquitoes live in every land region except for Antarctica and a few polar or subpolar islands. Iceland is such an island, being essentially free of mosquitoes.

The absence of mosquitoes from Iceland and similar regions is probably because of quirks of their unpredictable climate. For example, in Iceland in mid-winter it frequently warms up suddenly, causing the ice to break, but then it can freeze again after a few days. By that time, the mosquitoes will have emerged from their pupae, but the new freeze sets in before they can complete their life cycle.