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EFFECTS OF DENSITY ON THE PROPORTION OF MALE AND FEMALE PUPAE IN GYPSY-MOTH POPULATIONS

Published online by Cambridge University Press:  31 May 2012

Yves Mauffette
Affiliation:
Department of Biology, McGill University, 1205 Avenue Docteur Penfield, Montreal, Quebec H3A 1B1
Luc Jobin
Affiliation:
Laurentian Forest Research Centre, PO Box 3800, Sainte-Foy, Quebec G1V 4C7

Abstract

The numbers of larvae and pupae of the gypsy moth, Lymantria dispar L., were monitored in southwestern Quebec from June through August 1980 at 13 sites. In 10 sites, the proportion of male pupae was significantly different from an expected proportion of 0.5. Linear-regression analyses of the proportion of male pupae on larval density showed a significant increase in the number of male pupae with increasing larval density. Changes in the sex ratio could be an important indicator of the dynamic state of a population, and should be considered in modeling the population dynamics of gypsy moth.

Résumé

Les populations larvaires et de chrysalides de Lymantria dispar L. dans 13 sites localisés dans le sud-ouest du Québec ont été évaluées entre le début juin et le mois d'août 1980. Le nombre de chrysalides mâles dans 10 des sites échantillonnés était significativement différents de la valeur normale de 0.5. Les régressions linéaires obtenues de l'analyse du nombre de chrysalides mâles versus la densité larvaire indiquent une augmentation significative du nombre de chrysalides mâles avec l'accroissement de la densité des populations larvaires. Ces changements dans le rapport des sexes pourraient servir d'indices sur l'état et la dynamique des populations de la spongieuse.

Type
Articles
Copyright
Copyright © Entomological Society of Canada 1985

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