Monday, March 1

How do I explain it to my child ?: How insects get over winter

Ahen Maja the bee and her friend Willi wake up one day and feel paralyzed, they get very excited. “Why can I suddenly not move my arms or legs?” Maja asks. She gets the answer from a gravedigger. The beetle is so named because it feeds its offspring with the carrion of deceased organisms. He says: “The body temperature of us insects depends on the outside temperature. This means that when it gets cold outside, our bodies get colder too. Well, and because it’s so cold today, your arms and legs are stiff. ”In science there is a technical term for such animals – they are called cold-blooded. The grave digger hides that. He prefers to assure you that you won’t be killed anytime soon, because it has to get a lot colder.

Kai Spanke

This shows that the beetle is quite well informed, but not a real researcher like Jürgen Tautz. Because he worked as a professor at the University of Würzburg and knows everything about bees. For example this: “If you put a single bee in a vessel that is slowly cooled down, it will be unable to move from ten degrees. If you keep cooling, it dies at four degrees. ”So the temperature doesn’t have to be as low as the gravedigger wants us to believe to be dangerous for Maja and Willi. Bees aren’t stupid though, well, Willi maybe a little. In any case, they like to team up in winter to display life-saving behavior: power cuddling. So they survive even the iciest nights.

Photo gallery

Snuggle up or fly away?

Insects’ survival tricks in winter

What exactly happens there? If it gets frosty outside, the bees fall back on a supply of honey that they have stored in the honeycomb of their hive as provisions for uncomfortable times. Small problem: honey, as you know from home, hardens quickly when you store it in a cool environment. Since the insects don’t have teeth to nibble on the precious fuel, they have to do something else. Therefore, they move close together and form the so-called winter cluster, in the center of which the queen is located. If it gets colder than ten degrees, the little animals tremble with their flight muscles and use it to heat – friction generates heat – the environment for a day to summery thirty degrees. Jürgen Tautz says: “The honey liquefies, the bees ingest it – and have new energy. Then the whole gang cools down again. ”After a few days, the shrewd little guys repeat the trick.

Sounds simple, but it’s an unbelievable strain. In thirty minutes, a six-legged powerhouse burns 0.03 calories – for a population of forty thousand, that makes a total of one thousand two hundred calories. A person would have to jog for about two hours to get this result. Madness! But why don’t the bees take off when they turn on their heating? Quite simply because the aircraft engine is running at full speed while the wings do not move at all. According to Jürgen Tautz, it’s like taking the car out of gear and pressing the gas – the car howls, but doesn’t move from the spot. A bee uses this technique to generate peak temperatures of forty-four degrees, with the heat being stored in its central part. Your abdomen remains cold. In this way, no energy is lost if she cuddles head first so deeply into the group of her fellow species that only her bottom is visible.

Other strategies against frost are similarly ingenious. Like us humans, three quarters of insects are made of liquid. While blood flows in our veins, they have what is known as hemolymph. If ice crystals form in it, the cells burst, which leads to immediate death. In order to prevent this, nature came up with an ingenious idea: How about equipping some insects with some kind of antifreeze? Would that help? And whether that would help! For example, ladybugs, some mosquitoes and hornets have glycerin in their hemolymph. It is sugar alcohol that lowers the freezing point of water. Thanks to this trick, a hornet does not have to get nervous even at minus fifteen degrees. If you want and have glycerine at home, you can check the effect. Put one container with just water and one with glycerin and water in the freezer. After a while the water will freeze while the mixture remains liquid.

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In contrast to bees, bumblebees, wasps and hornets do not have the whole state buzzing through the winter. Only the mated queens survive and spend the cold months in cracks, piles of leaves or in attics. Jürgen Tautz says: “You fold your wings on your stomach between your legs so that you are protected from injuries. That looks totally crazy. ”Ants do it differently again. They retreat into the depths of their burrows underground, where it is always a little warmer than on the frozen ground. Butterflies, on the other hand, can overwinter in all their stages: as an egg, as a caterpillar, as a pupa or as an adult butterfly. It depends on the species. Some take refuge in our cellars, others have glycerine in their hemolymph. The handsome admiral even goes on a wandering trip, much like migratory birds do. If it gets too cold for him here, he can fly hundreds of kilometers south.

Even more answers to curious children's questions

Even more answers to curious children’s questions

An illustrated selection of articles in our column “How do I explain it to my child?” Has been published by Reclam.

To the publisher’s website

So you can see: insects have found fascinating ways to get through the winter. If you want to support them, you should leave leaves and dead wood in the garden. There are many hiding spots in it that invite you to crawl. In addition, it makes sense to set up an insect hotel, build small piles of stones and cut back perennials only in May. Such simple measures save Maja, Willi and all their nice colleagues from being picked up too early by the gravedigger.

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