Many ways to stick the landing: novel righting strategies allow spotted lanternfly nymphs to land on diverse substrates

Abstract

Many small animals use aerial righting to mitigate the risks associated with falling, such as predation, starvation, and desiccation. Spotted lanternflies (Lycorma delicatula) (SLFs) are invasive insect pests that often fall from host plants in response to predators or abiotic factors (e.g., wind). We used high-speed video to study whether immature SLFs (nymphs) impact surfaces, and subsequently land upright, more often than expected by chance, and, if so, whether they do so via active or passive mechanisms. SLF nymphs were found to adopt a stereotypical falling posture proposed to promote passive righting, and similar to those assumed by falling insects, spiders, geckos, frogs and skydivers. Live SLF nymphs landed upright in more trials when releasing voluntarily (100%) or when dropped from tweezers (56%) than did dead specimens (33-35%), with differences being highly statistically significant, even when the dead specimens were posed in the falling posture. These results support a role for active aerial righting. The fraction landing upright also did not depend significantly either on orientation during release or at first impact. We found that significantly more live SLFs reoriented to upright after impacting in a non-upright orientation via bouncing in combination with adhering to the substrate with one or more feet. Videos of nymphs landing on leaves confirmed that these insects can use similar tactics to land upright on host plants. These findings indicate the important role post-impact righting plays in determining final orientation, and highlight the importance of studies that include ecologically-relevant substrates and naturalistic conditions.

Putting a new spin on insect jumping performance using 3D modeling and computer simulations of spotted lanternfly nymphs

“…(Table 2) While landing attempts were disproportionately successful for impact on the ventral surface, SLF nymphs were able to land securely for all orientations at impact. They did so by grasping the surface by one or more tarsi while rotating rapidly and bouncing, similar to the capabilities observed for falling SLF nymphs landing on leaves (Kane et al, 2021) and for frogs landing on sticks (Bijma et al, 2016). This ability is of particular importance in their natural environment, where foliage landing spots present themselves at all orientations and locations, the ground is likely covered with clutter, and many landing targets recoil on impact.…”

“…This ability is of particular importance in their natural environment, where foliage landing spots present themselves at all orientations and locations, the ground is likely covered with clutter, and many landing targets recoil on impact. Thus, landing success can be enhanced by a number of behaviors, including achieving a preferred orientation when possible, but also by negotiating the aftermath of collisions so as to cling to the target (Jayaram et al, 2018;Kane et al, 2021;Reichel et al, 2019;Siddall et al, 2021).…”

“…4C): the forelegs and midlegs are fully extended laterally, while the hindlegs are extended rearward and crossed; 4) impact and landing or failure to land: the insect assumes a variety of postures. (Kane et al, 2021).…”

“…SLFs jump as a dominant form of locomotion to disperse, find food and habitat, and evade predators (Nixon et al, 2021). Like many other insects, they also need to be able to land on complex landscapes formed by densely-clustered leaves oriented at random, unpredictable angles (Graham and Socha, 2020;Kane et al, 2021;Zeng et al, 2020). In this study, we present the first exploration of SLF jumping biomechanics using an interdisciplinary approach that utilizes both empirical data on jumping kinematics using high-speed 3D video, detailed 3D rendered models, and computer simulations of the resulting trajectories and rotational dynamics.…”

“…Second, we studied whether SLF nymphs can reorient their bodies while in the air (attitude control), to facilitate landing. Such aerial reorientation can be a passive consequence of aerodynamic drag and body posture (e.g., dragonflies (Fabian et al, 2021), pea aphids (Ribak et al, 2013), spiders (Yanoviak et al, 2015), SLF nymphs (Kane et al, 2021), and springtails . CC-BY 4.0 International license available under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity.…”