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Laboratory experiments with flavored and untreated polystyrene spheres revealed major differences in taste discrimination among diverse taxa of freshwater zooplankton. Copepods showed the strongest responses to flavor treatments. Both nauplii and copepodites of calanoid (Diaptomus) and cyclopoid (Cyclops) copepods selected flavored spheres over untreated(More)
Acute toxicity experiments with purified toxins show that four species of zooplankton differ markedly in their physiological sensitivity to cyclic peptide hepatotoxins from Microcystis ueru-ginosu (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(More)
We used laboratory experiments with ten Daphnia taxa to test for links between Daphnia P-content, growth rate and habitat preference. The taxa represent a wide range of body sizes and most show distinct preferences for one of three habitats: shallow lakes, deep, stratified lakes or fishless ponds. Previous studies show that taxa from shallow lakes and(More)
It has recently been shown that Daphnia can vary in the phosphorus (P)-content of their body tissues, but the relative importance of genetic versus environmental causes for this variation is unexplored. We measured variation in P-content (as % body mass) of Daphnia from eight lakes and conducted experiments to contrast three sources of variation:(More)
Models of feeding and digestion predict that increased body size should result in longer gut passage time and improved assimilation efficiency. We examined the implications of digestion theory for size-structured interactions in a generalist zooplankton herbivore by studying the relationships between body size, ingestion rate, gut passage time (GPT),(More)
Daily measurements of mass and phosphorus (P) were made for Daphnia magna feeding on a high concentration (1 mg C l−1) of P-sufficient (molar C:P = 70–80, `P+') or P-deficient (C:P = 1000, `P−') green algae (Scenedesmus obliquus or Ankistrodesmus falcatus). Animals feeding on P+ algae for 12 d showed a sharp decline in growth during the last juvenile instar(More)
Two comparable methods were used to study the feeding of four species of Daphnia on large spherical particles which differed in size and hardness. The first method used gut analysis to estimate the selectivities of daphnids feeding in a broad size range of a single particle type, including polystyrene beads (4–60 µm diameter) in the laboratory and Eudorina(More)
Laboratory radioisotope experiments were used to investigate the effects of phytoplankton seasonal succession on the selectivity and clearance rates of a suspension-feeding copepod in two Indiana lakes. Responses to particle size and quality were tested by allowing adult female Diaptomus birgei feeding in natural seston to select between a small (6×7 μm)(More)
The dynamic interactions among nutrients, algae and grazers were tested in a 2 × 3 factorial microcosm experiment that manipulated grazers (Daphnia present or absent) and algal composition (single species cultures and mixtures of an undefended and a digestion-resistant green alga). The experiment was run for 25 days in 10-L carboys under mesotrophic(More)
Hunnicutt, Rachel E. M.S., Purdue University, December 2013. Emerald Ash Borer Adult Feeding Behavior and Ash Tree Management Decision Modeling: Relationships Between Pest and Host Tolerance Gradients. Major Professor: Jordan M. Marshall. Emerald ash borer (Agrilus planipennis Fairmaire, Buprestidae) is an invasive pest, introduced from Asia that attacks(More)