Winter delicate or wild? Ask the banded woolly bear, Pyrrharctia isabella — Bug of the Week

I often consider caterpillars as fairly delicate creatures and marvel why woolly bears don’t spend winter in a extra sturdy stage like an egg or pupa, as do many different moths and butterflies. Even in Maryland polar vortices typically go to and drop temperatures beneath zero. A captivating research by Jack Layne and his colleagues revealed that woolly bear caterpillars survive winter’s chilly via a course of referred to as supercooling. As temperatures drop in autumn and early winter, woolly bears and lots of different species of bugs produce cryoprotectants, antifreeze-like compounds together with glycerol and sorbitol, that stop the formation of deadly ice crystals of their our bodies. This brew of Mom Nature’s antifreeze permits caterpillars to outlive even when ambient temperatures dip effectively beneath freezing. The flexibility to shrug off chilly allows the partially grown woolly bear caterpillar to overwinter as a larva, and with the return of heat temperatures in spring and arrival of recent leaves, the caterpillars resume feeding for some time earlier than spinning a cocoon and finishing the transformation to an grownup moth.

Think about my delight when on a current journey to the sector, I found a banded woolly bear caterpillar with nearly no black bands on its physique save for just a few darkish segments close to the pinnacle. What with wildly inflating gas costs and my historic furnace gulping gallons of gas oil, the prospect of decrease oil payments loomed massive. These hopes had been completely dashed every week later once I noticed a banded woolly bear with however just a few orange coloured segments within the center and large black bands at head and tail sanctioning the Farmer’s Almanac forecast of extreme climate forward. Has discord so rampant on the earth of people unfold to the realm of woolly bears as effectively? Let’s hope not. Maybe these seemingly disparate meteorological predictions are reconciled like this: “Woolly bears are predicting a comparatively delicate winter with intermittent intervals of extreme chilly.” Intelligent meteorologists are these woolly bears.

Acknowledgements

Bug of the Week thanks Sheri, Finn, and Iggy for uplifting this episode and Karin Burghardt for offering photos and figuring out featured caterpillars. David Wagner’s outstanding e-book, “Caterpillars of Japanese North America”, was used to arrange this story, as was the attention-grabbing article “Chilly Hardiness of the Woolly Bear Caterpillar (Pyrrharctia isabella Lepidoptera: Arctiidae)” by Jack R. Layne, Jr., Christine L. Edgar, and Rebecca E. Medwith.