The Female to Male Ratio (FMR) in Hookworm

Female to male ratio (FMR) in hookworms of different species has been found almost in- variably, in the literature consulted, to be higher than unity. In 57 mongrel dogs, infected artificially by the oral route with A. caninum, this was also found to be the case, and there was a rough but statistically significant correlation between FMR and length of the infection. FMR's closer to unity are usually found in the lower reaches of the intestine. It is suggested that these findings are due principally to a faster overall displacement of males down the intestinal canal with resulting greater rate of loss.