Last week I wrote about the snow fleas hopping all over my ski tracks. Turns out lots of insects have similar strategies for dealing with winter weather.
Some go dormant, entering a state called “diapause”. That’s a state of dormancy that might look like hibernation but isn’t. It’s used as a way to survive temperature extremes, drought, or other unfavorable conditions. Insects that spend the winter in diapause can withstand a temperatures as low as 94 degrees below zero Fahrenheit (-70 C).
How do they do it? Some have antifreeze compounds that supercool their body fluids and tissues – sort of like ethylene glycol used in antifreeze for cars. Other insects freeze, turning into bugsicles – like the Arctic Woolly Bear caterpillar that Amy Hansen writes about in her book,
Bugs and Bugsicles.
Bugs and Bugsicles: Insects in the Winter
By Amy Hansen; illustrated by Robert C. Kray
32 pages, ages 7-9; Boyds Mills Press
In Bugs and Bugsicles, Hansen shows the diversity of strategies insects use to survive winter. Unlike the grasshopper of Aesop’s Fables fame, many insects begin their winter preparations while the weather is still warm. In late summer Monarch butterflies get ready to fly to Mexico, honeybees cap off their cells full of pollen and nectar, and ants stockpile seeds of all sorts and sizes.
Dragonfly nymphs curl up in the mud. Not only does the mud protect nymphs from cold, but it hides the nymphs from hungry fish. Ladybugs are more gregarious – they snuggle in hidden ladybug clusters until spring returns. And some insects go to sleep or, like the Arctic Woolly Bear, freeze until spring thaw.
Bug antifreeze works because, as the temperature drops, their cells produce glycerol (or other compounds). These compounds prevent water crystals from forming within the cells – and that’s important, because water freezes and any ice crystals would rupture the cells and kill the insects.
Hansen includes some hands-on investigations for curious bug-ologists- but here’s one you can try. You’ll need 2 ice cube trays, a couple cups, a measuring cup, some sugar and a freezer (or a really cold day).
Mix 1/2 cup of sugar with 1 quart of water. Fill up an ice cube tray with this solution.
You can read more about insects in winter here - and check out more science resources at STEM Friday! Review copy provided by publisher.