A simple method to estimate percentage parasitism when the host and parasitoid phenologies are unknown: A statistical approach

Abstract

When host and parasitoid phenologies areunknown the estimation of the generationalpercentage parasitism poses severalmethodological problems. We developed a simplemethod, based on a statistical approach, tosolve that problem. An unbiased estimator wasfound, named μCR, of thegenerational percentage parasitism, and itsperformance was tested through the analysis ofdata from two host-parasitoid systems: Phyllonorycter crataegella (Clemens)(Lepidoptera: Gracillariidae) and Sympiesis marylandensis (Girault)(Hymenoptera: Eulophidae), and Pierisrapae L. (Lepidoptera: Pieridae) and Cotesia (Apanteles) glomerata (L)(Hymenoptera: Braconidae). The μCR estimator proved to be a goodapproximation of the generational percentageparasitism, but its 95% confidence intervalwas very wide. The performance of the μCR estimator was improved and the95% confidence interval was smaller when someinformation on host and parasitoid phenologieswas added. The results suggested that thesmaller interval μCR ± onestandard deviation would contain with a greatprobability the generational percentageparasitism.

DOI: 10.1023/A:1021258000572

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Cite this paper

@article{RuizNarvez2004ASM, title={A simple method to estimate percentage parasitism when the host and parasitoid phenologies are unknown: A statistical approach}, author={Edward A Ruiz-Narv{\'a}ez and Nelsy Castro-Webb}, journal={BioControl}, year={2004}, volume={48}, pages={87-100} }