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Abstract:
Abstract
Two greenhouses were set over small brooks near Schlitz/Hessen. During a period of two years (1970-1971) the emerging aquatic insects were collected daily. Detailed informations about emergence, phenology, sex-ratio, and dependence on temperature at the time of emergence are given for 103 species (roughly 136 000 individuals) of Ephemeroptera, Plecoptera, Trichoptera, Neuropteroidea, Coleoptera, Limoniinae, and Ptychopteridae. Data are shown on Tabs. 3-28. Phenological and ecological facts about the more abundant species are demonstrated in diagrams (4-37) and discussed.
A mortality rate of the Ephemeroptera is defined as a trap-habitat-effect and separately determined and discussed. The two brooks differ significantly in their faunal composition, and in the abundance of the different groups. Whereas in the Breitenbach Trichoptera dominate with 1829 indiv./m2/yr, Ephemeroptera were the most abundant group in the Rohrwiesenbach with about 1500 indiv./m2/yr.
In 1971 an additional smaller station was erected over each of the two brooks further upstream for control. The catches given in these control-stations differ in quality as well as in quantity from those in the greenhouses. This is explained by methodological faults inherent in common emergence traps.
