Discrimination between exploitative and interference competition between Cladocera and Keratella cochlearis
Large cladocerans can suppress rotifers through both mechanical interference competition (IC) and exploitative competition (EC) for shared food resources. The author assessed the relative extent by which small- and large-bodied cladocerans suppressed the rotifer Keratella cochlearis. The small-bodied cladoceran Ceriodaphnia dubia suppressed Keratella exclusively through EC, while a slightly larger species (Daphnia ambigua) and subadults (Daphnia pulex) of two much larger-bodied cladocerans suppressed Keratella primarily through IC. Suppression by EC occurred in all treatments only after food was depleted below the concentration necessary to support maximal rotifer population growth, while suppression by IC occurred at both high and low food concentrations. IC should favor invulnerable rotifer speices, many of which are large-bodied, while EC should favor rotifer species with low food requirements, which tend to be small-bodied. -from Authors
Macisaac, H. J. and Gilbert, J. J., "Discrimination between exploitative and interference competition between Cladocera and Keratella cochlearis" (1991). Ecology, 72, 3, 924-937.