Changes in the density and species composition of planktonic rotifers as well as their relationship to several environmental variables were studied at Dadian Lake, a shallow subtropical lake, which was completely dredged and reconstructed. Samples were taken monthly (2006-2009) at five stations. The total rotifer abundance exponentially declined and reached a relatively stable stage in 2009. Po...

Brachionus calyciflorus typically develops long, defensive spines only in response to a kairomone from the predatory rotifer, Asplanchna. However, in the absence of any environmental induction, females of some clones produce daughters with increasingly long spines as they age; late-born individuals can have posterolateral spines as long as those induced by Asplanchna: up to 50% or more of body ...

Since the advent of molecular phylogenetics, there is increasing evidence that many small aquatic and marine invertebrates--once believed to be single, cosmopolitan species--are in fact cryptic species complexes. Although the application of the biological species concept is central to the identification of species boundaries in these cryptic complexes, tests of reproductive isolation do not fre...

Most population models assume that individuals within a given population are identical, that is, the fundamental role of variation is ignored. Here we develop a general approach to modeling heterogeneous populations with discrete evolutionary time step. The theory is applied to population dynamics of natural rotifer populations. We show that under particular conditions the behavior of the inhom...

In order to address the dearth of information on Rotifera in Vietnam, and especially on rotifers inhabiting freshwater psammon in Southeast Asia, we collected and examined twenty-five hygropsammon samples from Bau Thiem Lake, Thua Thien Hue Province, central Vietnam. A total of eighty-nine species-level rotifer taxa were identified, belonging to 21 genera and 13 families. Of these, 48 taxa (54%...

The planktonic food web in extremely acidic mining lakes is restricted to a few species that are either acidophilic or acidotolerant. Common metazoans inhabiting acidic mining lakes with a pH below 3 include rotifers in the genera Cephalodella and Elosa. The life history response of Cephalodella acidophila to three environmental key factors, pH (2, 3.5, 5.0 and 7.0), temperature (10, 17.5 and 2...

Members of the ciliate group of protozoans are often observed in mass cultures of rotifers. In particular, Euplotes and Vorticella are common contaminating species. In this study, I examined the effect of the ciliates Euplotes sp. and Vorticella sp. on the growth of the rotifer Brachionus rotundiformis by conducting inter-specific and tripartite-specific mixed-culture experiments. The growth of...

Local adaptation is an important principle in a world of environmental change and might be critical for species persistence. We tested the hypothesis that replicated populations can attain rapid local adaptation under two varying laboratory environments. Clonal subpopulations of the cyclically parthenogenetic rotifer Brachionus calyciflorus were allowed to adapt to two varying harsh and a benig...