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EFFECTS OF SOME ENVIRONMENTAL FACTORS ON THE OCCURRENCE OF SECOND DIAPAUSE IN LABORATORY-REARED CHORISTONEURA FUMIFERANA (LEPIDOPTERA: TORTRICIDAE)1

Published online by Cambridge University Press:  31 May 2012

Arlene McMorran
Arlene McMorran
Affiliation:
Insect Pathology Research Institute, Environment Canada, Sault Ste. Marie, Ontario
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Abstract

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Environmental factors can significantly affect the occurrence of a second diapause in laboratory-reared Choristoneura fumiferana. Each of the following conditions resulted in significantly fewer larvae entering second diapause: incubating the eggs at a high relative humidity (95%); a pre-diapause period at 20 °C rather than 28 °C; a diapause period of 7 or 8 months rather than 4 months; and holding the feeding larvae at higher temperatures (24 °C and 28 °C as opposed to 20 °C). Late-emerging larvae had a greater tendency to enter second diapause.

Résumé

Les facteurs écologiques peuvent affecter considérablement la survenance d’une seconde diapause chez la Tordeuse des bourgeons de l’Epinette (Choristoneura fumiferana (Clem.)) élevée en laboratoire. Chacune des conditions suivantes avait pour effet la réduction importante du nombre de larves entrant en seconde diapause : incubation des oeufs à une haute humidité relative (95%); période de prédiapause à 20 °C plutôt que 28 °C; période de diapause de 7 ou 8 mois plutôt au lieu de 4 mois; maintien des larves en train de se nourir à des températures plus élevées (24 °C et 28 °C au lieu de 20 °C). Les larves émergeant tardivement tendaient davantage à entrer en seconde diapause.

Type
Articles
Information
The Canadian Entomologist , Volume 104 , Issue 10 , October 1972 , pp. 1649 - 1653
Copyright
Copyright © Entomological Society of Canada 1972

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