Size Restrictions on the Passage of Overwintering Halyomorpha halys (Hemiptera: Pentatomidae) Through Openings

Abstract

Intentional and unintentional openings in a building's envelope provide opportunities for unwanted pests to enter buildings. The brown marmorated stink bug, Halyomorpha halys (Stål), is one such pest, causing a significant domestic winter nuisance in many locations. One important means of pest control is exclusion, or blocking openings through which they can enter, although some openings are intentional and cannot be completely blocked without putting a building at risk. To help understand what size openings are relevant to entry, adult H. halys ready for overwintering were driven out of heated boxes through openings designed to limit passage by their lateral pronotal and dorsoventral dimensions. Pronotally limited holes of 8 mm wide were passed by only one female (3.3% of those tested), and no females and only one male (3.3%) passed through 7-mm-wide holes. For dorsoventrally limited slits, few (13%) of females passed through 4-mm-high slits, and no individuals passed through 3-mm-high slits. Dorsoventral heights and pronotal widths of 930 individuals collected in Virginia were measured. Females were consistently larger, with pronota averaging 8.33 mm wide to the males' 7.47 mm and heights at the point of leg movement restriction averaging 4.03 mm to the males' 3.50 mm. Based on experimental data and size data, we conclude that most H. halys individuals will be excluded by slits smaller than 3 mm and holes smaller than 7 mm.

Cavity Tightness Preferences of Overwintering Halyomorpha halys (Hemiptera: Pentatomidae)

“…In the sloped lid cavities, H. halys moved back into spaces not much larger than dorsoventrally limiting dimensions (Chambers et al 2019a). Therefore, we conclude that H. halys exhibits dorso-ventral thigmotaxis during winter shelter seeking.…”

“…However, most commonly available kinds of corrugated cardboard are 4 mm thick or less (Twede et al 2014), and the cardboard used in previous experiments was 3 mm thick (Bergh et al 2017). This material is less rigid than the hardboard in our laboratory experiments and prone to warping with moisture, but the 3-mm spacing it creates is less than the preferred tightness found in the laboratory experiment, and less than the exclusionary rigid dimensions (Chambers et al 2019a). We conclude that shelters with a single-spaced cardboard substrate of 3 mm are sufficient for capturing H. halys, and may be preferable to males.…”

“…Observations of overwintering aggregations suggest that H. halys prefer tight spaces (Lee et al 2014). However, rigid openings exclude most females at 4 mm and most males at 3 mm (Chambers et al 2019a ). The cloth, tarps, and wood piles from which they can be collected have varying and/or flexible opening and cavity sizes.…”

“…This inexpensive and easily built wooden box design has been used by researchers in the mid-Atlantic United States for several years, including the relatively flexible cardboard substrate. However, if this 3-mm spacing were rigid, it would exclude most males and all females (Chambers et al 2019a), which suggests questions about the tightness preferences of these insects, and optimal substrate spacing.…”

Influence of Landscape Factors and Abiotic Conditions on Dispersal Behavior and Overwintering Site Selection by Halyomorpha halys (Hemiptera: Pentatomidae)

“…Halyomorpha halys can enter potential overwintering structures through slits ≥3 mm and holes ≥ 7mm (Chambers et al 2019a), making physical exclusion challenging particularly for older homes (Inkley 2012). We were able to demonstrate that adult H. halys settle in significantly greater numbers in dry locations (χ 2 = 239; df = 1; P < 0.001) compared with those with increased moisture by a 2.7fold difference (Fig.…”