Demographic parameters and mixis of three Brachionus angularis Gosse (Rotatoria) strains fed on different algae

Abstract

Rotifers are one of the smallest metazoans, served as perfect material for evolution theories and excellent food resources to larva in aquaculture. Population dynamics of rotifers help to optimize culture conditions, and to understand selection of asexual and sexual reproduction types. We described population dynamics of three Brachionus angularis strains using the life table method, with three types of food. The following demographic parameters were analyzed: intrinsic rate of increase (r), net reproductive rate (R 0), generation time (T), average lifespan (L), and the total percentage of mictic females in the offspring. The results showed that there were significant effects of strain on the parameters except for R 0. However, the food type significantly affected r, R 0, T, and the total percentage of mictic females in the offspring. Demographic parameters differed among strains, showing the possible adaptation to local niches. In comparison to Chlorella pyrenoidosa, Scenedesmus obliquus served more nutrition to enlarge population size, and more mixis was induced in rotifer populations fed on it. © 2007 Elsevier GmbH. All rights reserved.