HYDROMERMIS CHURCHILLENSIS N. SP. (NEMATODA: MERMITHIDAE) A PARASITE OF AEDES COMMUNIS (DeG.) FROM CHURCHILL, MANITOBA, WITH OBSERVATIONS OF ITS INCIDENCE AND BIONOMICS

Abstract

Hydromermis churchillensis n. sp. is described. It is distinguished from other species of Hydromermis mainly by the fused spicules and pointed termini of both sexes. One to six larval nematodes may be found in a larva of Aedes communis (DeG.). They emerge to become free-living, molt, mature, mate, and oviposit in 2 months. Host activity is hindered, pupation prevented, and the host usually killed upon emergence of the worm. Worms are found occasionally in adult mosquitoes. Host reaction as encapsulation sometimes occurs. Ectocommensal protozoa are more common on uninfected than on parasitized mosquito larvae. At Churchill, Manitoba, approximately 10% of the mosquito larvae were killed, but in individual pools the percentage reached 80%. Nematodes were irregularly distributed in the forest and transition zones, but no correlation was found between the physical features of the pools and this distribution.