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A positive correlation between population size and egg-content in Metastrongylus apri (Gmelin, 1790)*

Published online by Cambridge University Press:  06 April 2009

J. B. Dixon
Affiliation:
Department of Pathology, Royal Veterinary College, London, N.W.1

Summary

Observations on the egg-content of 78 counted populations of Metastrongylus apri showed that there was a positive correlation between population size and mean egg-content per female. In bilateral infections within one host, a significant tendency was shown for the larger of the two populations to outstrip the smaller in mean egg-content per female. There was no correlation between sex-ratio and mean egg-content. It is suggested that the effect of the host's defences against individual parasites is mitigated when large numbers of parasites are present.

A positive correlation was found between the sex-ratios of populations in left and right lungs, and there was a significant predilection of M. apri for the right lung.

I am indebted to Dr S. Peto, Microbiological Research Establishment, Porton, Wilts, for statistical advice, and to T. Wall and Sons Ltd., Atlas Road, London, N.W. 10, for access to abattoir material.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1971

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References

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