Ref ID : 1575
M.J. McElhone; A comparison the gut contents of two coexisting lake-dwelling Naididae (Oligochaeta): Nais pseudobtusa and Chaetogaster diastrophus. Freshwater Biology 9:199-204, 1979
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The gut contents of Nais pseudobtusa and Chaetogaster diastrophus, two co-existing littoral-dwelling Naididae (Oligochaeta), differed over a period of one and a half years due to strong selection by C. diastrophus for specific diatom genera, Cymbella spp. and Navicula spp. In contrast, N. pseudobtusa showed less selection and the gut contents consisted mainly of detritus, diatoms and mineral particles. These differences in the food niche are likely to contribute to the co-existence of the two species in this habitat. Seasonal changes in the relative abundance of diatom genera in the habitat greatly influenced the gut contents of N. pseudobtusa; however, these changes had less influence on those of C. diastrophus. This and the highly selective nature of the gut contents of C. diastrophus suggests that the two species have different feeding strategies. It is suggested that C. diastrophus actively seeks out certain diatom genera in preference to other food items, while the unselective gut contents of N. pseudobtusa are more typical of an opportunist feeder.