Publications

phenotypic plasticity of daphnia pulex in the presence of invertebrate predators: morphological and life history responses.	morphological and life history traits of two clones of the cladoceran daphnia pulex were measured in the presence and absence of size-selective insect predators, the midge larva chaoborus flavicans, which preys on small daphnia, and the water bug notonecta glauca, which preys on large daphnia. the aim was to detect predator-induced phenotypic changes, particularly the effect of simultaneous exposure to both types of predators. other work has shown that in the presence of chaoborus americanus, da ...	1992	28312604
demographic costs of chaoborus-induced phenotypic plasticity in daphnia pulex.	it has been proposed that morphological defenses against predation have demographic costs. we measured the cost of a predator-induced morphological defense, using predaceous phantom midge larvae chaoborus americanus (insecta, diptera) and the prey species daphnia pulex (crustacea, cladocera). the induced defense is a neck tooth (and other pleiotropic structures) developed in juvenile d. pulex in the presence of c. americanus. laboratory life table experiments, in the absence of predation, indica ...	1990	28313251
seasonal patterns of total and energy reserve lipids of dominant zooplanktonic crustaceans from a hyper-eutrophic lake.	seasonal patterns of lipid reserves and lipid classes of dominant zooplankton in a hyper-eutrophic lake were examined in relation to algal food resources. triacylglycerol was the principle lipid energy reserve in all five species examined. during the height of the yearlyaphanizomenon flos-aquae bloom, lipid levels of the principle herbivores (daphnia pulex andleptodiaptomus sicilis) and an omnivore (diacyclops bicuspidatus thomasi), were at their lowest concentration, suggesting that this cyanob ...	1992	28313577
grazing resistance in nutrient-stressed phytoplankton.	grazing experiments were performed with the zooplankters daphnia pulex and daphnia magna, feeding on phosphorus-saturated and phosphorus-limited cells of two green algae (scenedesmus subspicatus and selenastrum capricornutum). p-limited algal cells passed largely intact through the gut and were thus spared from heavy grazing pressure. p-saturated algal cells, in contrast, were efficiently assimilated. structural and morphological changes in the p-limited cells most probably reduced their digesti ...	1993	28313818
chaoborus predation and life-history evolution in daphnia pulex: temporal pattern of population diversity, fitness, and mean life history.	the effect of predation by the aquatic dipteran larva chaoborus americanus on genetic diversity and life-history evolution in the cladoceran daphnia pulex was investigated in large replicate laboratory populations. instantaneous daily loss rates of clonal diversity and genetic variance for fitness indicate that 93-99% of initial genetic diversity can be removed from populations during the 8-12 generations of clonal reproduction that occur each year in natural populations. in the absence of preda ...	1991	28564082
the evolutionary ecology of an antipredator reaction norm: daphnia pulex and chaoborus americanus.	ponds containing the parthenogenetic zooplankter daphnia pulex with and without chaoborid predators were sampled over the course of a season. a significant (p < 0.05) spearman rank correlation was found between predator density and the expression of an antipredator defense (neckteeth) by the daphnia. the reaction norms (percent induction of a single genotype versus predator density) of clones isolated from predator-free and predator-rich habitats were determined in a laboratory setting. there wa ...	1991	28564128
the genetics of phenotypic plasticity. viii. the cost of plasticity in daphnia pulex.	in a heterogeneous world, the optimal strategy for an individual is to continually change its phenotype to match the optimal type. however, in the real world, organisms do not behave in this fashion. one potential reason why is that phenotypic plasticity is costly. we measured production and maintenance costs of plasticity in the freshwater crustacean daphnia pulex (cladocera: crustacea) in response to the presence of chemical signals from a predator, the insect chaoborus americanus. we looked a ...	1998	28568340
evolution of a predator-induced, nonlinear reaction norm.	inducible, anti-predator traits are a classic example of phenotypic plasticity. their evolutionary dynamics depend on their genetic basis, the historical pattern of predation risk that populations have experienced and current selection gradients. when populations experience predators with contrasting hunting strategies and size preferences, theory suggests contrasting micro-evolutionary responses to selection. daphnia pulex is an ideal species to explore the micro-evolutionary response of anti-p ...	2017	28835554
interaction of the red pigment-concentrating hormone of the crustacean daphnia pulex, with its cognate receptor, dappu-rpchr: a nuclear magnetic resonance and modeling study.	the primary sequence of the red pigment-concentrating hormone (rpch) receptor of the water flea, daphnia pulex, was used in homology modeling to construct the first 3d model of a crustacean g-protein coupled receptor, dappu-rpchr. this receptor was found to belong to the class a subfamily of gpcrs with a disulfide bridge between cys72 and cys150 and an ionic lock between arg97 and thr224 and thr220. nmr restrained molecular dynamics was used to determine the structure of an agonist, dappu-rpch, ...	2018	28837848
conservation of the notch antagonist hairless in arthropods: functional analysis of the crustacean daphnia pulex hairless gene.	the notch signaling pathway is highly conserved in all animal metazoa: upon notch receptor activation, transcription of notch target genes is turned on by an activator complex that centers on the transcription factor csl. in the absence of signal, csl assembles transcriptional repression complexes that display remarkable evolutionary diversity. the major antagonist of notch signaling in insects named hairless was originally identified in drosophila melanogaster. it binds to the drosophila csl ho ...	2017	28861687
pulsed light reduces the toxicity of the algal toxin okadaic acid to freshwater crustacean daphnia pulex.	this constitutes the first study to report on the reduction in toxicity of the dinoflagellate algal toxin okadaic acid after novel pulsed light (pl) treatments where ecotoxicological assessment was performed using a miniaturised format of the conventional in vivo freshwater crustacean daphnia sp. acute toxicity test. bivalves accumulate this toxin, which can then enter the human food chain causing deleterious health effects such as diarrhetic shellfish poisoning. this miniaturised toxicological ...	2018	29052147