Leaping Locomotion by an Insect-parasitic Nematode

Abstract

INVESTIGATIONS on the use of nematodes of the genus Neoaplectana for the control of pasture insects have led to studies on the behaviour of an unnamed species¹ referred to as ‘DD 136’ (ref. 2). When infective-stage juveniles of DD 136 were mixed with soil they migrated to the surface and were observed to move in either of two ways, by ‘bridging’ or by ‘leaping’. In the former the nematode assumed an erect position and waved its anterior end until it came into contact with another portion of the substrate, thus bridging the gap. The posterior end was then drawn up. If no ‘bridge’ was achieved, the waving motion eventually stopped and the nematode remained immobile in an erect position adhering to the soil by its bent ‘tail’ which lay along the soil surface (Fig. 1A). It would periodically form a loop by bending the anterior three-quarters of the body until contact was made near the posterior end, where a drop of water formed (Fig. 1B). From this position nematodes were observed to project themselves through the air for distances up to about 10 mm (Fig. 1C–F).