Seasonal Changes, Life Cycle, and Production of a Psychrophilic Chironomid (Propsilocerus akamusi) in a Chinese Lake

ABSTRACT

Seasonal changes, life cycle, and production of a psychrophilic Chirunomidae species, Propsilocerus akamusi (Tokunage), were studied in eutrophic Lake Donghu. The P: akamusi population was characterized by a single annual reproduction period during late November to December, and the larval growth mainly occurred in winter. Most of P. akamusi were univoltine, while some of them came to emergence in two years or more. The average density and biomass were 318.9 ind./m² and 0.57 g dry weight/m² during January 1998 to June 2000, respectively, but these values did not include any summer measurements since the larvae aestivated in the deep sediment layer and could not be sampled routinely in summer. The annual production of P. akamusi was 2.73g dry weight/m², and the corresponding production/biomass ratio was 4.60.