Some Arctic caterpillars can’t eat enough during summer to sustain transformation so they winter over frozen solid, protected by their blood’s antifreeze properties. It may take 14yrs before they build enough reserve to transform.
The Isabella Tiger Moth (Pyrrharctia isabella) 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. 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.