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

Abstract

Brown marmorated stink bug (Halyomorpha halys) (Stål) is a household nuisance pest that seeks shelter in buildings during the winter months. It has been found in a variety of cavities and spaces between building elements, as well as in the objects stored within buildings. This experiment examined the cavity tightness preferences for these insects as they settled in winter refugia. Adult overwintering H. halys were placed in two types of simulated refugia made from rigid material. Each type had a cavity of constant width, while one had a flat lid and constant tightness, and the other had a sloped lid that became tighter as insects moved inside. Adults were allowed to enter and settle, then their locations were recorded. In sloped lid cavities, H. halys tended to settle where the cavity tightness was between 4.5 and 5.5 mm. In the flat lid cavity boxes, H. halys tended to move all the way back. In both configurations, H. halys had a significant tendency to orient their heads towards the cavity entrance. A field comparison of cavity tightness in refugia with less rigid cardboard substrates was also performed, with spacers consisting of one or two layers of 3-mm cardboard. This comparison found differences in cavity selection by sex, with males more likely to pick single-spaced layers, and females more likely to select double-spaced layers. Understanding these preferences could be useful for collection, pest management, trap design, and study of impacts on structures.

Formation of overwintering aggregation of Halyomorpha halys (Hemiptera: Pentatomidae) in laboratory conditions

“…However, three times as many females as males were found settling in the experimental arena. This result is also not consistent with those from field experiments, in which more males were caught than female from wild populations during their dispersal to overwintering sites (Bergh et al 2017;Chambers et al 2020). This discrepancy may result from differences in the experiment duration between the studies: our experiments were conducted only for 24 hours, whereas traps were deployed for two months in the previous studies.…”

“…Overall, less than 30% of the released individuals exhibited overwintering behaviors, by which they crawled and settled in the experimental arena. Interestingly, this percentage is substantially lower compared to those from previous studies (Chambers et al 2020;Toyama et al 2006): previous experiments could induce around 50% or 85% of the released individuals to show the intended overwintering behaviors. The lower percentage of H. halys observed in this study may result from longer exposure of the insects to light during the experiment.…”

“…First, many insect species are known to prefer specific micro-structures that can provide a suitable environment for overwintering. H. halys search for micro-structures such as dry and tight crevices, after alighting on either artificial or natural larger structures (Chambers et al 2020;Cullum et al 2020;Inkley 2012;Lee et al 2014). Cullum et al (2020) found that more overwintering H. halys settled in dry traps than in wet ones.…”

“…Cullum et al (2020) found that more overwintering H. halys settled in dry traps than in wet ones. In addition, Chambers et al (2020) overwintering H. halys and found that they tended to settle where the cavity was between 4.5 and 5.5 mm wide. Overwintering individuals also moved away from the cavity entrance when settling in the cavity (Chambers et al 2020).…”

“…H. halys search for micro‐structures such as dry and tight crevices, after alighting on either artificial or natural larger structures (Chambers et al . 2020; Cullum et al . 2020; Inkley 2012; Lee et al .…”