When halys freezes over: Cold hardiness of brown marmorated stink bug (Halyomorpha halys)

Halyomorpha halys (Stål), the brown marmorated stink bug, is an invasive insect native to East Asia that has become a severe agricultural pest in the United States on over 33 crop host plants and has been detected in 41 states and two Canadian provinces. This invading insect is predicted to establish across the entire contiguous United States based on the geographic distribution of hosts, degree-day modeling, and ecological niche models. To date, however, we do not know how most environmental stressors, particularly cold temperature, may impact H. halys mortality.  Winter temperatures in northern states, such as Minnesota, can cause high mortality among insect pest species, often affecting the degree to which pest populations may exceed economically damaging levels in the following growing season. By using winter field acclimated and laboratory non-acclimated adult H. halys we determined that winter cold acclimation occurs in the field, ascertained the relationship between freezing and mortality, and found that it is possible to acclimate H. halys in a laboratory setting to achieve the same degree of cold tolerance as field acclimated adults. Additionally, it appears that acclimation may be concurrent with the induction of diapause. These results have implications for forecasting overwintering mortality given known winter temperatures, for determining H. halys’ cold tolerance strategy, and for using laboratory insects to study future cold hardiness and diapause questions.