MODE OF EXISTENCE AND SEASONALITY OF MIDGE LARVAE (DIPTERA, CHIRONOMIDAE) IN MAN-MADE LAKES IN THE COACHELLA VALLEY, SOUTHERN CALIFORNIA

Over the past 2 decades, numerous man-made ponds and lakes constructed in country clubs and on golf courses in the Coachella Valley have bec ome ideal habitats for various chironomid species. Large numbers of ad ult midges emerging from these water bodies pose nuisance and economic problems. During 1992 and 1993 we initiated comprehensive studies on the nature and scope of the nuisance midge problem in the valley. We s ampled on a biweekly basis 2 lakes supplied with well water, 2 supplie d with tertiary effluent water, and one supplied with a mixture of the se 2 sources, to determine the midge larval fauna and the mode of exis tence, seasonal abundance, and population trends of these midges. Clim bers, clingers, portable sand tube builders, and tube builders on plan ts predominated in well-water habitats with submerged vegetation and d etritus bottoms. Tube builders and burrowers predominated in the terti ary water, which characteristically had a detritus bottom, devoid of v egetation. Habitats holding a mixture of the 2 water types with sandy bottoms supported midge larvae known to be sprawlers.