Are there Host Strains within the Species of Syngamus trachea?

Abstract

In 1928 Taylor put forward the theory that “…Syngamus trachea is a species within which there may be found a number of strains showing a peculiar physiological adaptation to the host in which they occur.” He had not had much success in a number of experiments in which he had tried to infect chickens with S. trachea from starlings. The first experimental feedings resulted in only light infections though control experiments with the chicken “strain” resulted in much heavier ones. After the first passage through the chicken however, the gapeworms had become more adapted to the new host, and could produce much more serious infections in the next generation.