Spatial distribution of Tabanidae (adults and larvae) in two bogs of southern Quebec

In studies on the spatial distribution of tabanids in a bog and a fen in southern Quebec, 21 species of Chrysops, 13 of Hybomitra, 5 of Tabanus and 1 of Atylotus were recorded from adults collected in Malaise traps; 7 of these were found only in the bog and 4 only in the fen. Of the total number of species, 11 were also found as larvae during a simultaneous sampling survey of the peat moss substrate of these bogs (2 Chrysops, 8 Hybomitra and 1 Atylotus). Mean larval density was 1.49/0.1 m2, randomly distributed (Poisson distribution). The potential productivity was estimated to be about 146 000 larvae/ha. There was a significant difference in larval distribution between open sites and forested areas. The results of adult trapping and larval sampling are compared and discussed.