Demography and population growth ofAsplanchna girodi(Rotifera) as a function of prey (Anuraeopsis fissa) density

摘要

Laboratory studies on population growth and life table demography ofAsplanchna girodiwere conducted at 25±1 °c usingAnuraeopsis fissaas prey at four (250, 500, 1000 and 2000 ind ml−1) densities. A prey density of 100 ind ml−1per predator per day did not supportA. girodi, while at the highest prey concentration,A. girodireached a peak of 115±7 ind ml−1. The age distribution ofA. girodiindicated that non-adults constituted about 2/3rd of the population at all prey concentrations. A decrease in prey availability resulted in increased mortality of non-adults. At the highest prey density, the rate of population increase (r) was 1.51 d−1. The significance of estimating mortality in population growth studies is