Mechanism, kinematic performance, and fitness consequences of jumping behavior in entomopathogenic nematodes (Steinernema spp.)

The mechanism enabling entomopathogenic nematodes (Steinernema spp.) to jump is described. Jumping performance is measured and the contribution of jumping to host finding is estimated. We used the entomopathogenic nematode Steinernema carpocapsae as a model species for the genus. Nematodes jump using a two-step process of forming and contracting a loop. During loop formation, the nematode bends the anterior half of its body until the head region makes contact with the side of the body. The two body regions are held fast by the surface tension of the water film covering the nematode. When the loop is contracted, the body becomes contorted so that the cuticle kinks. This extreme bending generates and stores sufficient energy that when the surface-tension force is broken the nematode is propelled through the air. The nematode (0.558 mm in length) can jump a distance of 4.8 +/- 0.8 mm (mean +/- SEM) and a height of 3.9 +/- 0.1 mm. The contribution of jumping to host finding varies among species and is related to the foraging strategy used by each species.