Flat on its back: the impact of substrate on righting methods of the brown marmorated stink bug, Halyomorpha halys.

Many animals, including insects, need to solve the problem of self-righting if inverted and substrate is one understudied factor that could affect righting ability. In this study we ask the questions, how does Halyomorpha halys self-right and does variation in substrate affect self-righting? To address our questions we used four substrates with different features and filmed H. halys righting response on each substrate (n = 22 individuals). We also used two synced cameras to film the most common righting method and quantified its kinematics. Self-righting metrics did vary depending on substrate in terms of diversity of righting methods used, duration of the successful righting event, number of fails per attempt, and stance width. We also determined that the symmetrical forward flip is the most common method used by H. halys. In the forward flip H. halys creates a tripod of support using the hindlegs and the tip of the abdomen to elevate the anterior portion of the body off the substrate and pitch forward onto its feet. In addition to demonstrating that substrate can impact self-righting and quantifying the symmetrical forward flip, we also provide a foundation for future explorations of sensory feedback and adaptive motor control using H. halys.