Orientation of Tylenchorhynchus martini Swarmers to Chemical Stimuli

The use of swarming Tylenchorhynchus martini nematodes provided a rapid and efficient in vitro method for the study of nematode orientation mechanisms as affected by chemical stimuli. Orientation of the nematodes occurred in concentration gradients diffusing from agar discs containing 0.05, 0.1, 0.25 M of both AlCln and CdCL>, and 0.25 M of NH..C1. Attraction of the nematodes did not occur at the other concentrations tested: 0, 0.5, or 1.0 M, or with the other chemicals: MgCL, MgSOi, NaaSzOi^HsO, or ascorbic acid. There was no repulsion in any of these tests to nematodes. Swarming nematodes of Tylenchorhynchus martini (Fielding, 1956) have continual and rapid jerky movements which result apparently from attempts of individuals to break free from the sticky cuticle of swarmers (Hollis, 1958, 1960, 1962; McBride and Hollis, 1966). Hollis suggested that swarming may be conditioned by the state of polysaccharide, lipid, or protein substances of the cuticle and that it is characterized by innate morphological modifications of the cuticle. The use of the electron microscope revealed morphological modifications in the cuticle of swarming T. martini (Ibrahim, 1967). These modifications must be related to the sticky condition of the cuticle. Thus, the use of swarming T. martini provided a rapid and efficient in vitro method for the study of orientation mechanisms of