INTER- AND INTRA-SPECIFIC ASSOCIATIONS AS SOME POSSIBLE PREDATOR AVOIDANCE AND ENERGY CONSERVATION STRATEGIES IN PLANKTONIC ROTIFERS

Abstract

During routine analysis of zooplankton samples from Lake Midmar, a warm temperate impoundment, several associations involving rotifer species were observed. These included: 1) the linking together of individuals of Hexarthra mira and Trichocerca chattoni to form chains; 2) phoretic associations involving H. mira. T. chattoni and several cladoceran species, and 3) the second record for South Africa of the association between Ascomorphella volvocicola and Volvox sp. The possible advantages accruing to the animals involved in these associations are discussed in terms of predator avoidance and energy conservation in the limnetic zone of a lake.