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Comment by cowpig | Hacker News Reader

In a related question, I've always wondered how Mosquitoes survive winters. Where I live the winters are very cold, with entire months deep in the negatives. All water freezes.

Would entering a state of torpor be a sufficient explanation for surviving winter? Would they need some other mechanism for surviving frost?

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A very common adaptation among insects is producing large amounts of polyhydroxy alcohols like glycerol in the hemolymph that acts as anti-freeze or cryoprotectant depending on the species.

Doesn’t that question apply to pretty much all insects? I thought the answer is they are buried deep or preserved in small amounts of water that doesn’t freeze (water never freezes all the way through).

Certain amphibians (i.e. tree frogs) have a "natural anti-freeze" compound in their blood. This allows them to hibernate through 20°F freezes - without any cell walls rupturing due to ice spikes - and just thaw back out in the spring. Perhaps parent comment was wondering if a special subspecies of mosquito or mutation was capable of the same?

Not only do they survive, it seems like the worst mosquitoes I experience are in areas with spring snowmelt in progress, even when there is no obvious standing water anywhere nearby.

The latest Frozen Planet series shows a queen bee surviving winter in Siberian forest by digging down into earth and awakening in the spring thaw so other insects can do something like this or use eggs to do it.

I think eggs can survive below zero temperature, but not longer than 6 months.

In regions that are too cold, mosquitoes will just not thrive.

Increase the average temperature of one degrees and a lot of regions will welcome mosquitoes.

This can't be true. I lived on the Canadian Prairies, where it was normally below freezing for 6 months every single year, and below minus 40 for several weeks at a time, and yet there were tons of mosquitoes every summer.

Below freezing air, but it's not freezing just few centimeters underground or underwater.

You would have to go far more than a few cm underwater. We use ice bridges in the winter. A few cm of ice is not enough to support a giant truck.

frost line is like 6 feet underground in these places. There is permafrost in mosquito land!

this gives enough time for the eggs to hibernate and hatch.

for the eggs to die, there must be a lukewarm summer, and a long winter.

beyond that, it's also about averages.

I remember having snow on the ground every October, and it never leaving before April. I also remember having snow on the ground one year on my first day of school in August. They get hot summers though. Contrast that with the coast, when it's lukewarm summers, and barely a day with snow each year (lots of rain) but there are barely any mosquitoes.

> In regions that are too cold, mosquitoes will just not thrive.

Anyone who has visited canada's northern territories or alaska can assure you that mosquitos thrive in the far north.

Yeah there way fewer mosquitoes in Van than at the arctic circle.

It’s like the cold preserves them like a deep freeze.

And you can’t get much more standing water than in Vancouver.

I would expect the mosquitoes to die but their eggs to survive until warm enough

Who says they survive cold winter climates? They die out in colder climates and migrate back from temperate climates. Mosquitos may not be killed by frost, but frost is a layered phenomenon, a hard freeze definitely kills them.

I’m pretty sure that the mosquitos that show up almost instantly when things thaw in Alaska and Canada aren’t migrating from warmer climates. That would be pretty impressive, but no way do they move that fast.

Not impossible - things in Alaska and Canada thaw as the last, so the mosquitos could be already on their way long before the thawing there began.

However what I think is happening is that their eggs are what survives of them, and they hatch out quickly.

They can be very easy to miss as most of them piggyback on the great swarms of flying spiders, centipedes, and trees migrating north each year to repopulate the barren wastelands after the great freeze has killed all but the warm-blooded lifeforms.

I have to imagine a non-trivial number of them survive in areas with human settlements. Maybe they start getting more active when it warms up.

Probably not - they’re far worse where there aren’t humans for hundreds of miles.

Mosquitos in the tundra are insane [https://www.nationalgeographic.com/animals/article/150915-Ar...]

Interesting. I had heard caribou herds basically choose migration routes to avoid them so that makes sense.

> Who says they survive cold winter climates?

Anyone who put even a minute of effort into looking up the well-researched and publicly available information on the topic rather than defaulting to ignorance could have told you this.

Insects have numerous different strategies to make it through cold winters, either as eggs, larvae, or adults. Some can tolerate partial freezing, some lower the freezing temperature of their bodies in order not to freeze at subzero temperatures. These are combined with finding shelter inside tree stumps or bark, under leaves or rocks, or even underwater, granting them a layer of insulation and protection from the wind and the worst cold.

Here's a good starting point for those interested https://en.wikipedia.org/wiki/Insect_winter_ecology#Cold_tol...

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