Valle de Bravo reservoir supplies drinking water to 40% of Mexico City. Here we present data on the population growth and life-table demography cladoceran Daphnia pulex, cultured at temperatures 20 °C 25 with different concentrations crude extracts from blooms Microcystis aeruginosa, collected in January, Woronichinia naegeliana, September. We hypothesized that pulex would be more sensitive hig...

Improvements in sequencing technology over the past 5 years are leading to routine application of shotgun sequencing in the fields of ecology and evolution. However, the theory to estimate evolutionary parameters from these data is still being worked out. Here we present an extension and implementation of part of this theory, mlRho. This program can efficiently compute the following three maxim...

1. The growth rate hypothesis predicts positive relationships among growth rate (l), body RNA (%RNA of dry mass) and body P (%P of dry mass) contents. 2. We tested this withinand across-species by growing five species/clones of Daphnia (Daphnia magna, Daphnia pulex, Daphnia galeata and two isolates of Daphnia pulicaria) with different combinations of food quantity and stoichiometric food qualit...

Toxicity and temporal changes in toxicity of freshwater-marsh-microcosms containing South Louisiana Crude (SLC) or diesel fuel and treated with a cleaner or dispersant, were investigated using Chironomus tentans, Daphnia pulex, and Oryzias latipes. Bioassays used microcosm water (for D. pulex and O. latipes) or soil slurry (for C. tentans) taken 1,7, 31, and 186 days after treatment. SLC was le...

Mosquitofish are widely used for biological control of mosquito larvae in rice fields, but the presence of different types of vegetation or alternative arthropod prey affects the performance of the fish. Feeding experiments were conducted in 4 rice field vegetation zones. Overall, predation was maximal in young and mature rice, moderate in the submerged naiad vegetation, and minimal in areas of...

The hypothesis that a large zooplankton herbivore, Daphnia pulex, can competitively reduce the abundance of resident zooplankton when colonizing a community of small species was tested in two lakes. When introduced to enclosures in eutrophic Larimore Pond, D. pulex decreased phytoplankton abundance by an order of magnitude, resulting in drastically reduced densities of Tropocyclops prasinus and...

Acute toxicity experiments with purified toxins show that four species of zooplankton differ markedly in their physiological sensitivity to cyclic peptide hepatotoxins from Microcystis ueruginosu (microcystin-LR1 and Noduluria spumigenu (nodularin). The copepod Diaptomus birgei was most sensitive (48-h LC,, for microcystin-LR ranged from 0.45 to 1.00 pg ml-l), Daphnia pulicuriu was least sensit...

Zooplankton body size shows a strong association with temperature, competition, and predation. Global warming affects all three drivers of is thus expected to lead substantial changes in zooplankton community composition distributions. To disentangle the isolated joint effect fish predation on species biomass zooplankton, we monitored population biomasses Daphniidae that differ (Daphnia magna, ...

Hybridization plays a potentially important role in the origin of obligate parthenogenesis (OP) in many organisms. However, it remains controversial whether hybridization directly triggers the transition from sexual reproduction to obligate asexuality or a hybrid genetic background enables asexual species to persist. Furthermore, we know little about the specific genetic elements from the diver...