Helminths in Rana pipiens Schreber, and Bufo hemiophrys Cope, from the Delta Marshes, Manitoba

Abstract

Nine species of helminths were found in speciments of Rana pipiens (5 of trematodes, 3 of nematodes, and 1 of cestodes), and nine is speciments of Bufo hemiophrys (5 of trematodes, 3 of nematodes, and 1 of acanthocepahalans) from Delta. Four helminth species occurred in both hosts. Evidence suggested that the separation of Rhabdias bufonis and R. ranae is doubtful. Nine new host records and one new Canadian record were established. Anurans living mainly in a semi-aquatic environment were parasitized by higher numbers and more kinds of helminths than anurans living mainly in a terrestrial environment. Larger anurans had more kinds of helminths than smaller anurans. No significant difference was found in the intensity of helminthic infections between males and females of a particular host species. A statistical comparison of the expected and observed cases of juveniles and adult helminths in lungs suggested an antagonism between trematodes and nematodes. Changes in the extensity and intensity of infections were related to the habits of the definitive hosts and the lifecycles of the helminths.