This genus includes many species living at high latitudes and altitudes, in tundra and taiga ecosystems. Some have two-year (semivoltine) life cycles and only occur as adults every other year; typically the caterpillar larva overwinters to pupate in spring, with the moths flying around midsummer, but some species eclose later, their moths flying from late summer into autumn. "Xestia" caterpillars are generally stout and cryptically colored; in some species they have quite prominent dark lengthwise spots, but may e.g. be entirely green or whatever else gives best camouflage.