1. Daphnia pulex and Daphnia middendorffiana are commonly found in the Toolik Lake region of arctic Alaska. These two species are very similar morphologically, although their natural distributions differ markedly: D. pulex is restricted to shallow ponds, while D. middendorffiana is widely distributed and found in a variety of ponds and lakes. We compared the reproductive capabilities of D. pule...

Changing environmental calcium (Ca) and rising cyanobacterial blooms in lake habitats could strongly reduce Daphnia growth and survival. Here, we assessed the effects of maternal Ca in Daphnia on transfer of resistance to their offspring against Microcystis aeruginosa PCC7806 (M. aeruginosa). Laboratory microcosm experiments were performed to examine effects in Daphnia carinata (D. carinata) an...

The cladoceran crustacean Daphnia pulex has served as a standard organism for aquatic toxicity testing for decades. The model organism status of D. pulex rests largely on its remarkable ability to rapidly adapt morphologically, physiologically and behaviorally to a wide range of environmental challenges, as well as on its parthenogenetic reproduction and ease of laboratory culture. As in all mu...

The genetic background of inducible morphological defences in Daphnia is still largely unknown. Dissolved infochemicals from the aquatic larvae of the phantom midge Chaoborus induce so-called 'neck-teeth' in the first three post-embryonic stages of Daphnia pulex This defence has become a textbook example of inducible defences. In a target gene approach, by using three Daphnia genotypes which sh...

In shallow subarctic ponds Daphnia and their algal food are often exposed to solar ultraviolet radiation (UVR). It was previously demonstrated that direct exposure of Daphnia to UVR may result in sublethal damage to Daphnia‘s intestinal system. This led to the hypothesis that, as consequences of such exposures, Daphnia may be experiencing a situation similar to starvation. We examined, in contr...

It is known that cyanobacteria negatively affect herbivores due to their production of toxins such as protease inhibitors. In the present study we investigated potential interspecific differences between two major herbivores, Daphnia magna and Daphnia pulex, in terms of their tolerance to cyanobacteria with protease inhibitors. Seven clones each of D. magna and of D. pulex were isolated from di...

Ecotoxicological endpoints based on behavioral traits (e.g., predator avoidance, feeding, and locomotion) may be more sensitive and give more insights into patterns of sublethal toxicity than survivorship tests. In this study, the density-dependent grazing rate of Daphnia pulex pre-exposed to p,p'-dichlorodiphenyldichloroethylene (DDE) (insecticide metabolite) and glyphosate (herbicide), via wa...

The fourth Daphnia Genomics Consortium Meeting was held from July 7th through July 9th, 2007 at Indiana University (Bloomington, IN, USA). This year’s meeting was entitled The Genome Biology of the Model Crustacean Daphnia and was highlighted by the initial public release of the draft version of the Daphnia pulex genome. In collaboration with the US Department of Energy Joint Genome Institute (...

When individuals from multiple populations colonize a new habitat patch, intraspecific trait variation can make the arrival order of colonists an important factor for subsequent population and community dynamics. In particular, intraspecific priority effects (IPEs) allow early arrivers to limit the growth or establishment of later arrivers, even when competitively inferior on a per-capita basis...

Paland and Lynch (Reports, 17 February 2006, p. 990) showed that in Daphnia pulex, the ratio of amino acid replacement to silent substitution in mitochondrial genes is higher in asexual lineages than in sexual lineages. If this base-composition bias is maintained by selection, it too should alter following transitions in reproductive mode. Analysis reveals no such change in the genomes of D. pu...