Biology of Alaskan Black Flies (Simuliidae, Diptera)

Sommerman, K; Sailer, R; Esselbaugh, C

There are 38 species of black flies known from Alaska, 35 of which were taken by members of the 1948 Alaska Insect Project. Life histories are given for most of these species. The local distribution of the breeding places of the various species is determined in general by the temperature requirements of the immature forms, whereas minor factors such as stream speed, depth, or substratum often account for the absence of a species at a particular location along a stream. The different habitats studied may be grouped into three major categories, dependent chiefly upon elevation as expressed in the following generalization: Base low is the lowest elevation in the area, and critical elevation is 400 feet above base low. UPLAND--The study location above the critical elevation, or without regard to elevation, the water from the major area of watershed coming from springs. SEMI-UPLAND--The study location below, but the major area of watershed above the critical elevation. LOWLAND--The study location and the major area of watershed below the critical elevation. In addition, if the water from the major area of watershed passes through impoundage the study location is automatically transferred to the next lower category. If the major area of watershed is below the critical elevation and to a large extent consists of bogs the study location is automatically transferred to the next higher category. If considerable bog drainage and impoundage are involved they may offset each other. Species of Gymnopais dichopticus, G. holopticus, and Prosimulium fulvum are typically found at upland habitats. The absence of P. alpestre and hirtipes or the presence of Simulium latipes and aureum in general is indicative of lowland habitats. The known species distribution in the three habitat categories is shown in table form. Species occurring in habitats representing one or more of the categories appear earliest and generally develop more rapidly in the warmest habitats.

Biology of Alaskan Black Flies (Simuliidae, Diptera)

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