A study of the relationships between the mouthparts and food habits in several species of freshwater calanoid copepods

Abstract

The mouthpart morphology of five species of freshwater calanoid copepods was examined with light microscopy and compared with their diets. Limnocalanus macrurus has sharp teeth and stout mouthparts with clawlike setae, structures that have been associated with predaceous feeding. Diaptomus sicilis and Senecella calanoides have blunt teeth and slender mouthparts which seem suited for herbivorous feeding. The mouthparts of Diaptomus shoshone and Epischura laeustris have structures intermediate between those of the other two groups, suggesting an omnivorous mode of feeding. Results of gut analyses show that L. macrurus is predominantly predaceous, D. sicilis is exclusively herbivorous, and the other three species are omnivorous. Thus the diet of S. calanoides is not correctly predicted by the structure of its mouthparts, indicating the limitation of using mouthpart morphology to predict diet.