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Prey Depletion By Odonate Larvae: Combining Evidence From Multiple Field Experiments, Clay L. Pierce, Dan M. Johnson, Thomas H. Martin, Charles N. Watson, Robert E. Bohanan, Philip H. Crowley Oct 1987

Prey Depletion By Odonate Larvae: Combining Evidence From Multiple Field Experiments, Clay L. Pierce, Dan M. Johnson, Thomas H. Martin, Charles N. Watson, Robert E. Bohanan, Philip H. Crowley

Clay L. Pierce

In this paper we re-analyze previously published data regarding the response of several prey populations to manipulation of predaceous larval dragonfly (Insecta: Odonata) densities in four separate field enclosure experiments. Using a computer-intensive "rerandomization" approach to testing hypotheses, we show that the individual experiments were not sufficiently powerful to consistently reject false null hypotheses. Combining the data from three comparable experiments, we can enhance the power associated with such tests. Three prey categories (Trichoptera, Oligochaeta, and large Cladocera), constituting less than one-third of the typical odonate diet, were found to be consistently depleted in enclosures with odonate larvae; but the …


Physiological Response Of Rainbow Trout (Salmo Gairdneri) To Acute Fenvalerate Lntoxication, Steven P. Bradbury, James M. Mckim, Joel R. Coats Jan 1987

Physiological Response Of Rainbow Trout (Salmo Gairdneri) To Acute Fenvalerate Lntoxication, Steven P. Bradbury, James M. Mckim, Joel R. Coats

Steven P. Bradbury

The physiological responses of rainbow trout (Salmo gairdneri) to fenvalerate intoxication during aqueous exposure were examined to provide information about the pyrethroid mode of action in fish. Trout (n = 4) were exposed to 412 ± 50 μg/liter fenvalerate and died in 10.9 ± 1.5 hr. Brain, liver, and carcass fenvalerate concentrations associated with mortality were 0.16 ± 0.05, 3.62 ± 0.57, and 0.25 ± 0.05 mg/kg, respectively. Visible signs of intoxication included elevated cough rate, tremors, and seizures. Histopathological examination of gill tissue showed damage consistent with irritation. An evaluation of respiratory-cardiovascular and blood chemistry responses indicated an elevated …