Understanding the buckling instability in jumping nematode and inspired soft model

Nematodes are abundant in most ecosystems, playing a pivotal role in soil health and nutrient recycling. In these environments, they primarily exhibit behaviors such as swimming and crawling locomotion. A few nematode parasites of insects in the genus Steinernema possess the ability to leap toward the host. During the jumping process, these entomopathogenic nematodes (S. carpocapsae) form an alpha shape with capillary latch and upon reaching their buckling limit, a kink configuration enables them to achieve high-velocity jumps (~10 bodylength/s). In this study, we designed a soft jumping model by drawing inspiration from nematode leaping using buckling, which showed similar jumping behavior and performance. We explored various parameters such as aspect ratio, kink instability, and the effect of moduli on jumping capabilities. By combining these biological insights with engineering principles, a soft jumping mechanism is devised, holding the potential to offer opportunities for soft limbless locomotion and actuators.