Abstract
The predatory effectiveness of the planarian, Dugesia dorotocephala , against populations of chironomid midges and mosquitoes in earthen experimental ponds was studied during the summers of 1975, 1976 and 1977. In 1975, inoculation levels of 10 and 25 planaria/m super(2) of pond surface area produced reductions of 28.5% and 52.3%, respectively, in populations of Dicrotendipes) sp., Tanytarsus spp., Procladius spp. and Cricotopus spp. midges. In 1976, the midge larvae were reduced by 36.5%, 51.0% and 58.3% at levels of 25, 50 and 100 planaria/m super(2), respectively. In 1977, levels of 25 and 50 planaria/m super(2) produced 37.8% and 47.5% midge control, respectively. The planaria in inoculated ponds persisted throughout each evaluation period, and showed slight population increases, but these increases were inconsistent and nonproportional to their initial inoculation densities.