Procedure for mass collection of mermithid postparasites (Nematoda: Mermithidae) from larval blackflies (Diptera: Simuliidae)

A method of collecting postparasitic Neomesomermis flumenalis from larval Prosimulium mixtum/fuscum and Simulium venustum is described. The larval blackflies were collected by sweeping them with paint brushes from rocks into buckets of stream water. The larvae were obtained free of debris by placing them in battery jars into which air was bubbled a few centimetres below the surface, the larval blackflies migrated into the current and were collected from the sides of the jar. The blackfly larvae were held at 10 deg C and all emerging N. flumenalis were collected daily. Using this procedure between April and July 1973, 4,378 postparasitic N. flumenalis were obtained from about 250,000 blackfly larvae of mixed species from Newfoundland streams.ADDITIONAL ABSTRACT:Larvae that were of Prosimulium mixtum Syme & Davies or P. fuscum Syme & Davies, or both, together with those of Simulium venustum Say were collected from natural populations in Newfoundland and maintained in the laboratory for emergence of the Mermithid parasites, Neomesomermis flumenalis. Between April and July 1973, 4378 postparasitic larvae of N. flumenalis were obtained from about 250 000 Simuliid larvae. The techniques used in maintaining the Simuliids in the laboratory are described..