Comparison of chironomids and other macroinvertebrates associated with Myriophyllum spicatum and Heteranthera dubia

Macroinvertebrate communities inhabiting exotic Eurasian milfoil (Myriophyllum spicatum L.) and native water stargrass (Heteranthera dubia (Jacq.) MacM.) macrophytes were studied from March 1999 to June 2000 in experimental ponds constructed to simulate reservoir wetlands. Although macrophyte architecture explained some variation in macroinvertebrate abundance between the two macrophytes, most variation was explained by the sampling months. Total. number of macroinvertebrates was positively correlated with epiphyton biomass, and epiphyton biomass was significantly different between the two plant species and among sampling months. Taxa richness did not vary between the two plant types. Chironomid larvae were the most abundant. organisms and were dominated by Apedilum elachistum on both plant species. Annual production of five chironomid species was estimated by the size-frequency method. Apedilum elachistum exhibited the highest productivity 9.9 g dry wt m(-2) yr(-1) of plant surface area on M. spicatum and 8.5 g dry wt m(-2) yr(-1) on H. dubia.