The arctic woolly bear moth's caterpillar life cycle may extend up to how many years?

Gynaephora groenlandica, the arctic woolly bear moth, is an erebid moth endemic to the high Arctic, specifically the Canadian archipelago and Greenland. It is best known for its slow rate of development, as its full caterpillar life cycle may extend up to 15 years, and 4 years may elapse between molts. This species remains in a larval state for the vast majority of its life. Unique among Lepidoptera, it undergoes an annual period of diapause that lasts for much of the calendar year, as G. groenlandica is subject to some of the longest, most extreme winters on Earth. In this dormant state, it can withstand temperatures as low as −70 °C.

This species has an alpine subspecies which is notable for its geographic distribution south of the High Arctic. Females generally do not fly, while males are much more active in this capacity. The arctic woolly bear moth also exhibits the behavior of basking, which aids in temperature regulation and digestion and affects both metabolism and oxygen consumption. G. groenlandica may also represent a useful indicator species for the effects of global warming in the High Arctic due to temperature-based feeding tendencies.