The mermithid (Nematoda) and other endoparasites of simuliidae (Diptera) in insular Newfoundland

• Main Author: Ebsary, B. A. (Barry Alan)
• Format: Thesis
• Language: English
• Published: Memorial University of Newfoundland 1973
• Subjects: Newfoundland
• Online Access: https://research.library.mun.ca/4118/; https://research.library.mun.ca/4118/1/Ebsary_BarryAlan.pdf; https://research.library.mun.ca/4118/3/Ebsary_BarryAlan.pdf

In 1971 and 1972, 198 streams in insular Newfoundland were examined for blackfly endoparasites. Forty streams yielded one or more species of the microsporida-- Thelohania bracteata, T. fibrata, Plistophora simulii, Caudospora simulii and C. brevicauda. The fungus Coelomycidium simulii was found in 14 streams. The blackfly mermithids Gastromermis viridis, Isomermis, wisconsinensis and Neomesomermis flumenalis were recovered from 59 streams. Central Newfoundland had higher frequencies of mermithid infections (47.3-75.0%) than the more coastal areas (11.7-36.3%). The longitudinal distribution of mermithid infected blackflies within the stream showed that the upper 400 m. of the stream were devoid of mermithids, while the lower reaches of the stream harboured mermithids. Current, depth and chemical parameters of the stream water in streams with and without mermithids were examined. Mermithid parasitism did not appear to be significantly affected by these factors. Neomesomermis flumenalis was redescribed in light of the finding of eggs and pre-parasites. Adult males of G. viridis and I. wisconsinensis were also redescribed. The life cycle of N. flumenalis was described. Following emergence from the host, male and female post-parasites molt to adults in 9-15 days at 12°C., 10-13 days at 18°C., 37-40 days at 6°C., and failed to molt at 22-24°C. A double pre-adult molt and a parasitic molt were noted. Mating lasted for 12-24 hours, and usually occurred within a few hours of molting to adults. Eggs were laid 36-59 days after mating. Females laid 600-650 eggs over 3 days. The incubation period was 35-55 days at 12°C.; heaviest egg hatching occurred 4-11 days after the onset of hatching. No eggs were laid at 3°, 7°, 18°, or 22-24°C. Pre-parasites live 2-3 days. The period from emergence from the host to egg laying was 45-74 days, and from emergence to egg hatching, 80-129 days. Mixed infections involving microsporida, mermithids and coelomycidians were noted. Seasonal fluctuations of host/parasite populations in Half Moon ...