The nature of the adhesion of Corynebacterium rathayi to the cuticle of the infective larva of Anguina agrostis

The relationship between Corynebacterium rathayi and the infective second stage ‘dauer” larva (DL₂) of Anguina agrostis has been studied with particular regard to the nature and extent of bacterial adhesion to the nematode. Viability of the 1-year-old DL₂ was high, the number of dead specimens per gall only ranging from 5.1% to 8.3%. The DL₂ were exposed to C. rathayi either from cultures or galls and the numbers with and without adhering bacteria were counted. A total of 22,917 DL₂ from 15 galls were examined, the mean number of DL₂ per gall being 1,528. The mean percentage per gall of DL₂ with bacteria adhering was 42%. However there was much variability (from 0 to 98%). The significance of galls with DL₂ that did not succumb to bacterial adhesion is discussed. The sequence of events associated with the process of bacterial adhesion to the nematode cuticle was examined with the aid of the electron microscope. The process involves fusion of the glycocalyx with the bacterial capsule followed by thickening and, at times, displacement of the epicuticle together with changes in the main body of the cuticle. The possible nature of the process of adhesion is discussed.