Submitted to: Journal of Invertebrate Pathology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/4/2008
Publication Date: 2/2/2009
Citation: Shapiro Ilan, D.I., Campbell, J.F., Lewis, E.E., Elkon, J.M., Kim-Shapiro, D.B. 2009. Directional movement of parasitic nematodes in response to electrical current. Journal of Invertebrate Pathology. 100:134-137. Interpretive Summary: Steinernematid nematodes are small round worms that are used as environmentally friendly natural insecticides. It is important to understand what kinds of stimuli the nematodes respond to in order to find and infect insect pests. In this study we discovered that these insect-killing nematodes respond to electrical fields. We observed that one species that usually likes to ambush its prey moves toward the electrical source, whereas another nematode species that is a more active seeker of its prey tends to move away from the electrical source. We hypothesize that these nematodes use electrical stimuli to find suitable insects to parasitize.
Technical Abstract: Steinernematid nematodes are parasites that are important natural regulating agents of insect populations. The infective juvenile nematodes respond to a variety of stimuli that aid in survival and host finding. Host finding strategies among steinernematids differ along a continuum from ambush (sit & wait) to cruiser (search & destroy). In this paper we describe directional movement in response to an electrical current, which was generated on agar plates. Specifically, Steinernema glaseri (a cruiser) moved to a higher electric potential, whereas S. carpocapsae, an ambusher, moved to a lower electric potential. Thus, we hypothesize that steinernematids may detect electrical currents or electromagnetic fields in nature, and these stimuli may be used differentially among species for host finding or enhancing other fitness characters.