Effect of starvation time on the prey capture behaviour, functional response and population growth of Asplanchna sieboldi (Rotifera)

Abstract

1. We examined the effect of different periods of prior starvation(from 30 min to 16 h) on the prey capture behaviour, and functional and numerical responses of the predatory rotifer Asplanchna sieboldi using the rotifer Brachionus calyciflorus as prey.2. Feeding activity (i.e. encounter, attack, capture and ingestion) by Asplanchna increased significantly with increasing prey densities from 2 to 16 mL−−1 and with increasing prior starvation periods from 0.5 to 8 h.3. Asplanchna sieboldi showed a type II functional response at all the prior starvation periods tested. The asymptotic prey density was highest after 8 h of starvation.4. The instantaneous population growth rate of A. sieboldi ranged from 0.089 ± 0.044 (when starved for 8 h in every 24 h and at a prey density of 2 individuals mL−−1 for the other 16 h) to 1.015 ± 0.142 in the control (no starvation and at a prey density of 16 individuals mL−−1). The effect of starvation time on the numerical response was evident only at the higher prey density.