Foliar-phenolics
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Epirrita autumnata
Autumnal Moth
Epirrita autumnata, the autumnal moth, is a geometrid moth native to northern Fennoscandia and the Palearctic region. Its larvae feed primarily on mountain birch (Betula pubescens ssp. tortuosa and ssp. czerepanovii) foliage, with outbreaks capable of defoliating extensive birch forests. The species exhibits cyclic population dynamics with outbreak and non-outbreak phases. Eggs overwinter in diapause, showing exceptional cold hardiness with supercooling points reaching −36.5 °C. Adult females suffer substantial predation pressure from invertebrate predators, particularly harvestmen.