Landscape-level evaluation of the effect of winter temperatures on summer trap catches of male gypsy moths (Lymantria dispar)

The gypsy moth was introduced into the United States in 1869, and has been expanding its range ever since. This invasive species is univoltine with an obligate overwintering in the egg phase. Lack of sufficiently cold winter temperatures may limit range expansion southward in the United States, whereas lethal winter temperatures may present a climatic barrier to northward expansion. Insights into overwintering mortality, as well as associated climate change scenarios, have primarily originated from physiological models incorporating developmental responses to temperatures and field studies of egg mass mortality. Here, we attempt to find an association between annual winter temperatures and subsequent male moth trap catch from northern Minnesota, which represents a northern extreme of its current distributional range in North America. We study this dynamic in the arrowhead region of Minnesota, during the establishment and persistence phases of invasion from 2004 to 2012.