Diet and habitat characteristics of Pagastiella ostansa (Diptera : Chironomidae)

Winter distribution and diet of Pagastiella ostansa (Diptera: Chironomidae) were investigated in Big Brewer Lake, Kent Co., Michigan. Big Brewer Lake is a small (34.4 ha), shallow (Zmax=7.5 m), meso-to-eutrophic lake. P. osta nsa larvae were found at only two littoral zone stations characterized by s oft, organic sediments and Chara sp. beds. Larval P. ostansa gut content an alysis compared with sedimentary algal assemblages indicated selective fora ging and ingestion of large, benthic, pennate diatoms. Winter diet included the diatoms Navicula oblonga, Navicula cryptocephala, Nitzschia sp. 2, Sta uroneis anceps, Stauroneis phoenicenteron, and Pinnularia maior, whereas mo re common blue-green algae and small and colonial diatoms present, in the s ediment assemblage were not ingested.