Submitted to: Entomologia Experimentalis et Applicata
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/14/2016
Publication Date: 1/21/2017
Citation: Bergh, J.C., Morrison III, W.R., Leskey, T.C. 2017. Characterizing spring emergence of adult Halyomorpha halys (Hemiptera: Pentatomidae) using overwintering shelters and pheromone traps. Entomologia Experimentalis et Applicata. 162:336-345.
Interpretive Summary: Factors that trigger spring emergence of adult brown marmorated stink bugs (BMSB) from overwintering sites were investigated. Studies were conducted in 2013 and 2014 using experimental wooden and cardboard overwintering shelters. Pyramid traps (baited with BMSB pheromone plus synergist or unbaited) were used to establish if BMSB exiting shelters in the spring immediately responded to the pheromone. We checked the shelters and traps on a weekly basis counting the number of BMSBs that emerged or were caught, respectively. We found that BMSB emergence in the early spring was associated with warmer temperatures, while a much larger peak occurred as day length stabilized closer to the summer solstice. Because captures in the pyramid traps and overwintering shelters were not correlated with each other, it is likely that BMSB must make a dispersal flight in the spring before becoming responsive to their pheromone. These results will contribute to our understanding BMSB biology and ecology and to interpretting trapping data.
Technical Abstract: We investigated the spring emergence of overwintering Halyomorpha halys (Stal) and the environmental cues that triggered emergence. Adults were collected from overwintering sites, marked, and re-settled in experimental shelters deployed in screened cages in six woodlots across three Mid-Atlantic states during winter 2013 and 2014. At each site, one shelter was placed in a closed cage and a second was placed in a cage with the top removed, enabling emerged adults to be counted or to disperse, respectively. At each site, eight pyramid traps encircled the shelters (four pheromone-baited, four unbaited). Weekly or twice weekly counts of adults emerging into the closed cage and of marked and “wild” (unmarked) H. halys adults in traps were conducted from mid-winter through early July. In both years, a small peak of emergence occurred in mid-April, a larger and more prolonged peak was observed between mid-May and early June, and emergence ended by early July. In early spring, emergence was positively correlated with weekly degree day accumulations, while in late spring emergence was positively correlated with the rate of photoperiod change. The majority of adults were captured in pheromone-baited traps and of the greater than 440 adults captured, only three marked individuals were recaptured. There was no correlation between weekly numbers of adults that emerged and captures in traps. These results suggest that degree days and photoperiod cues trigger emergence of overwintering H. halys and that adults may require a dispersal flight before responding to traps baited with its aggregation pheromone and pheromone synergist.