Laboratory rearing of Halyomorpha halys: methods to optimize survival and fitness of adults during and after diapause.
Laboratory colonies are necessary to conduct year-round research on the invasive brown marmorated stink bug, Halyomorpha halys (Stål), a severe agricultural and nuisance pest in the USA. When adults are collected in the fall to either start or supplement colonies, they require a period of cold storage before they resume sexual development and egg production. There is a lack of understanding of how to collect and store diapause-triggered adults in the laboratory. A series of experiments in 2013-2015 assessed survival and fecundity of stink bugs collected from different locations and stored under different temperatures and durations. We found that a minimum of 7 weeks is necessary to break diapause and that a substantial proportion of adults can survive when stored at constant 9°C, even for periods longer than needed to terminate diapause. Adults survived significantly better at 6 and 9°C than at 3°C in storage for 7 weeks. Longer durations up to 34 weeks in storage reduced adult survival and significantly affected survival rates, timing of first egg laying, and overall fecundity. Location where adults were collected at overwintering sites in the fall had a significant impact on survival in cold storage and colony performance. Adults collected from soybean fields in mid-September and fed in the laboratory for 2 weeks before storage had lower survival than adults collected in October at aggregation sites and stored immediately. The food sources available to H. halys adults at collection locations for nutrition and sequestration of sufficient energy reserves going into diapause are discussed.