What if mosquitoes disappeared?

Mosquitoes buzz around on summer evenings. Some bite and make you itchy.

What if there were no mosquitoes at all? Would anything miss them?

There are about 3,500 kinds of mosquitoes in the world. Only the females bite: they need a meal of blood to make their eggs. The males never bite at all and live on flower nectar.

Many people would be happy to see mosquitoes go. But scientists ask a careful question: what jobs do mosquitoes do in nature, and could other animals do them instead? In this thought experiment you will look at both sides and make up your own mind.

Mosquitoes (family Culicidae) number around 3,500 species. Females of many species take blood meals to produce eggs; males depend entirely on nectar, and females also drink it. Only some species bite people at all; some wetland species feed mainly on frogs and other amphibians.

This thought experiment removes every mosquito species and asks what would follow for food webs, for flowers and for human health. It is a real debate among scientists, and the honest answer includes a good deal of uncertainty.

Baby mosquitoes live in water. Fish eat them.

Grown-up mosquitoes are eaten by dragonflies, birds and bats. Some mosquitoes visit flowers.

Mosquitoes start life in water as wriggling larvae and grow into flying adults. All kinds of animals eat mosquitoes, including fish, turtles, dragonflies, migrating songbirds and bats.

Mosquitoes also drink nectar from flowers, and some help pollinate them. Scientists in Washington State found that local mosquitoes pollinate the blunt-leaf orchid, a small wildflower of cool northern places, attracted by its scent. Male mosquitoes depend on nectar completely.

National Geographic lists fish, turtles, dragonflies, migratory songbirds and bats among the animals that eat mosquitoes. A bat biologist quoted there, Winifred Frick (UC Santa Cruz), notes that no bat species specializes in mosquitoes; most bats are generalist insect-eaters.

Mosquitoes also visit flowers. Researchers from Virginia Tech and the University of Washington (PNAS, 2020) showed that in Washington's Okanogan-Wenatchee National Forest, local mosquitoes pollinate the blunt-leaf orchid (Platanthera obtusata) but not its close relatives, drawn by a scent rich in nonanal with a little lilac aldehyde.

Without mosquitoes, some fish and birds would need other food.

Some flowers might need other visitors. And there would be no more itchy bites!

Take away every mosquito and some animals would lose part of their food. Fish, turtles, dragonflies, songbirds and bats that eat mosquitoes would have to eat other insects instead. Many scientists think most of them could switch, because there are plenty of other insects. Others are less sure.

Flowers that mosquitoes visit, like the blunt-leaf orchid, might need other pollinators. And because some kinds of mosquitoes can carry germs that make people sick, there could be fewer of those illnesses.

Ecologically, the main losses would be prey for aquatic and aerial insectivores and some pollination. Many experts expect generalist predators to switch to other insects; disease ecologist Marm Kilpatrick (UC Santa Cruz) told National Geographic that, asked whether the average person would notice, his hunch would be 'no', though 'we don't know the answer'.

The US Fish and Wildlife Service has cautioned that removing mosquitoes entirely could have consequences we can't predict, and Winifred Frick worries that heavy pesticide spraying could harm bats more than losing mosquitoes. The health side is clearer: diseases carried by mosquitoes, such as malaria, would no longer spread by mosquito bites.

Lots of animals eat many kinds of insects. They might eat other insects instead.

Scientists are not sure, so they think about it carefully.

Scientists find this question hard for three reasons. First, there are about 3,500 kinds of mosquitoes, and they live very different lives: some wetland mosquitoes feed mostly on frogs and are not interested in people at all. Second, most of the animals that eat mosquitoes also eat lots of other insects, so they might just switch. Third, the ways people might try to remove mosquitoes, like spraying chemicals, could harm other animals too.

So scientists have to weigh the good a world without mosquitoes might do against risks they cannot fully predict.

Three things make the question hard. Mosquitoes are diverse, with about 3,500 species and very different habits; some wetland species feed mainly on amphibians and are not interested in humans, and malaria is spread by some female Anopheles mosquitoes, not by mosquitoes in general. Most of their predators are generalists, so removal might be absorbed, but local exceptions are possible. And removal methods carry their own risks: Frick notes that broad pesticide use could be more harmful to bats than the loss of mosquitoes as prey.

Any real decision would therefore weigh a clear health benefit against ecological effects that are probably modest but genuinely uncertain.

Doctors and scientists work hard to stop illnesses that some mosquitoes carry.

Mosquitoes lay their eggs on or near water. Their babies grow up in the water.

Some kinds of mosquitoes can carry germs that cause illnesses, such as malaria. The World Health Organization says malaria can be prevented and cured, and it is mostly found in tropical countries.

Mosquitoes lay their eggs on or near water, or in places that may fill with water. The larvae that hatch live in the water, then turn into pupae and finally into flying adults. The whole life cycle usually takes about two weeks.

The World Health Organization estimates 282 million malaria cases and 610,000 malaria deaths in 80 countries in 2024, with 95 percent of both in the WHO African Region. Malaria spreads mostly through the bites of some infected female Anopheles mosquitoes, and it is preventable and curable (WHO fact sheet, updated December 2025).

So the case for removing mosquitoes rests mainly on human health, while the case for caution rests on uncertainty about ecosystems and the side effects of removal methods. Weighing those two is a real scientific and ethical question, which this lab leaves open.