Datensatz

Zusammenfassung

Development times of Diamesa incallida and its numbers of generations per year were studied using in situ rearings in conjunction with continuous collection of egg masses from the field. The evidence suggested that the crenophilous D. incallida laid eggs throughout the year and produced eight to ten generations per year, depending on water temperature (7.6°C to 8.0°C). This is the first proof for a multivoltine Diamesinae as well as for continuous egg laying behaviour by a non-tropical chironomid. The comparatively large mature larvae (9.6 mm, 710 µg a.f.d. weight) and the numerous generations per year indicate that D. incallida is a highly productive component of crenal communities. The importance of rearing chironomids over a sufficient number of generations is emphasized as a basis for the reliable interpretation of field data.