Ecology of Simuliidae, Mermithidae, and Microsporida in Newfoundland freshwaters.

Abstract

Prosimulium mixtum/fuscum S. &D., Cnephia mutata (Malloch), C. dacotensis D. &S., Simulium aureum Fries, and S. gouldingi Stone are univoltine. S. venustum Say, S. vittatum Zett., S. tuberosum (Lundstrom), S. corbis Twinn, S. latipes (Mg.), and S. decorum Walker are multivoltine. Neomesomermis flumenalis (Welch), Gastromermis viridis Welch, and Isomermis wisconsinensis Welch are univoltine. The eggs of Prosimulium and Cnephia species hatched synchronously with a batch of the eggs of N. flumenalis. The eggs of the first generation of Simulium species hatched synchronously with the eggs of G. viridis and I. wisconsinensis, and the overwintered batch of eggs of N. flumenalis. The larvae of subsequent generations of Simulium species were not infected by mermithids. Mermithid infections occur during the hatching and buildup of blackfly larval population.Caudospora simulii Weiser and C. brevicauda Jamn. occur in Prosimulium and Cnephia species during the cold seasons. Thelohania bracteata (Strickland, 1913), Pleistophora simulii (Lutz and Splendor, 1904), P. multispora (Strickland, 1913), and Coelomycidium simulii Debaisieux occur in Simulium species during the warm seasons. G. viridis and I. wisconsinensis overwinters in the egg stage, and N. flumenalis overwinters partly in the egg stage and partly as parasites in P. mixtum/fuscum. S. venustum and P. mixtum/fuscum are the most prevalent and abundant of the simuliids. N. flumenalis is the most prevalent and abundant of the mermithids and P. multispora is the most abundant of the microsporidans. Aeshna interrupta Walker and Rhyacophila fuscula (Walker) prey on S. venustum larvae.