Backyard Biodiversity October 2020 Woolly Bears...not actually bears...but cuter
The woolly bears are out and about this time of year. Those cute fuzzy black and rusty brown,orangish caterpillars found traipsing across the lawns and sidewalks.
All moths and butterflies belong to the insect order Lepidoptera, meaning scale wing, because when you look up close at the wings you will see they are covered in tiny, flattened hairs or scales (check out this neat close up pic of a butterfly wing https://www.sciencelearn.org.nz/images/543-butterfly-wings-are-covered-with-scales “Science Learning Hub – Pokapū Akoranga Pūtaiao, University of Waikato, www.sciencelearn.org.nz). But back to the caterpillars.
Why do these guys always seem to appear in the fall? And where are they going?
Woolly bears are the caterpillar (or larval) form of the Isabella tiger moth (Pyrrharctia Isabella) which is found from northern Mexico into southern Canada (bugguide.net/node/view/154649) . The caterpillars themselves are covered in short bristles or hairs, unlike some caterpillars, these hairs do sting or hurt when touched. They usually have a black front and back end with a band or rusty orange in the middle.
In the fall they are out searching for more food or perhaps a nice, cozy spot under some fallen leaves or under a decaying log to overwinter.
Unlike the monarch butterflies which migrate during winter, the caterpillars of the Isabella tiger moth will overwinter in northern regions. This species can be found all the way up into the Arctic. The caterpillars of this species can literally remain frozen over winter, using cryoprotectant to help protect its tissue and organs from the effects of freezing. Cryoprotectants are sugars, proteins and other chemical compounds that can help protect organs and tissue from freezing. Different compounds act in different ways to accomplish this. One way is to the lower the actual freezing temperature so that the cells and tissue never actually freeze and maintain their integrity. Many insects, amphibians and fish can produce these anti-freeze compounds when the temperatures get chilly, so as to survive in cold weather and habitats. The woolly bear caterpillars can thus safely overwinter, and in the spring time they will spin a fuzzy cocoon before emerging as an adult tiger moth.
Legend has it the woolly bear caterpillar can predict the severity of a winter.
The wider the rusty, orange band of hairs in the middle, the milder the winter. However, researchers believe that the amount of black versus orange depends more on the age of the caterpillar. The caterpillars molt several times before reaching adulthood and with each molt they shed their skin and bristles and change color.
Regardless, they are a pretty cute and always a treat to see.
According to legend we should have a mild winter, but I do not know, maybe he is just old. I moved him away from a busy street and placed in some nice leaf litter in our backyard, good luck little dude.
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