The Colonization of California Rice Paddies by Chironomid Midges

Abstract

Temporal changes in the population structure of the colonist species of chironomids were determined from replicated rice plots flooded at 2 different times. These studies were conducted in 1974 and 1975 at the Rice Research Facility, University of California, Davis Farm and the Co-operative Rice Research Station, Biggs, California [USA]. The chironomid community consisted of larvae from Paratanytarsus sp. nov., Tanytarsus sp. nov., 6, Cladotanytarsus sp. nov., Cricotopus sylvestris (Fab.), C. bicinctus (Meigen), Paralauterborniella spp. and Procladius spp. Most samples were usually characterized by 1 predominant species (Davis plots) or 1-3 co-dominant species (Biggs plots). Previously reported species of economic importance, Cricotopus sylvestris, Paralauterborniella spp. and Paratanytarsus sp. nov., were usually recorded in intermediate abundance but the latter species assumed dominant status in some 1974 Biggs samples. While species richness was similar in both localities, the Davis plots supported greater numbers of larvae. Diversity (D) and rank correlation (.gamma.) patterns were usually similar between plots flooded at different times at the same locality. Dissimilar abundance-rank patterns existed between localities at comparable sampling intervals.