ABSTRACT
Soil nematodes possess a rich variety of intriguing behaviors, including chemotaxis, thermotaxis, osmotic avoidance, and dauer formation and recovery. Mutants defective in each of these behaviors have been isolated for the free-living nematode Caenorhabditis elegans, permitting detailed behavioral analyses. Infective juveniles of entomopathogenic nematodes are more motile than the respective third-stage juveniles of the normal developmental cycle. The soil is the natural reservoir for entomopathogenic nematodes, and these organisms have evolved at least three major behavioral strategies for persistence in this buffered environment: aggregation, inactivity, and anhydrobiosis. Active movement has advantages to entomopathogenic nematodes, because it increases chances for encountering a susceptible host and for survival by permitting escape from unfavorable habitats. Dispersal is a behavioral mechanism entomopathogenic nematodes use to locate habitats for survival and infection. There are two major behavioral components to infection: host-finding and penetration. Studies of infective stage behavior in the natural habitat, soil, are formidable, restricting present research to consequences rather than processes.
