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Pyrrharctia isabella
The Isabella Tiger Moth can be found in many cold regions, including the Arctic. The banded Woolly Bear larva emerges from the egg in the fall and overwinters in its caterpillar form, when it literally freezes solid. First its heart stops beating, then its gut freezes, then its blood, followed by the rest of the body. It survives being frozen by producing a cryoprotectant in its tissues. In the spring it thaws out and emerges to pupate. Once it emerges from its pupa as a moth it has only days to find a mate. In most temperate climates, caterpillars become moths within months of hatching, but in the Arctic the summer period for vegetative growth - and hence feeding - is so short that the Woolly Bear must feed for several summers, freezing again each winter before finally pupating. Some are known to live through as many as 14 winters.
Recent research has shown that the larvae of a related moth Grammia incorrupta (whose larvae are also called “woollybears”) consume alkaloid-laden leaves that help fight off internal parasitic fly larvae. This phenomenon is said to be "the first clear demonstration of self-medication among insects".
2 Comments
Thank-you Annvan. Self medication and cryoprotectants are not typically something I think about in moths. It is truly amazing to think that this species has these abilities! :-)
Nice shots and fascinating info!