Horizontal transmission of Parathelohania anophelis to the copepod, Microcyclops varicans, and the mosquito, Anopheles quadrimaculatus

Abstract

The copepod Microcyclops varicans was infected with Parathelohania anophelis by uninucleate meiospores from a field-collected fourth instar Anopheles quadrimaculatus larva. Large numbers of uninucleate, pyriform spores developed in the copepod. These spores were fed to early instar A. quadrimaculatus larvae, infecting both males and females, resulting in the production of cylindrical, binucleate spores in the adult. These spores were responsible for vertical transmission, through the eggs, to the larvae. The original spore type collected from the field was found in the male progeny from the infected females. Another P. anophelis-infected mosquito colony was established by feeding spores from a single, field-collected, infected copepod to A. quadrimaculatus larvae. The microsporidium was continuously maintained by vertical transmission in newly established, infected colonies.