Influence of inter-tree variation in time of budburst of white spruce on herbivory and the behaviour and survivorship of Zeiraphera canadensis

Abstract.

• 1 Field studies were carried out during 4 years to determine the effects of inter-tree variability in the time of budburst of white spruce, Picea glauca Moench (Voss.), on the distribution, behaviour and survivorship of, and herbivory by, the spruce bud moth, Zeiraphera canadensis Mutt. & Free.
• 2 Differences between trees in herbivory, bud moth density and survivorship were inversely related to the mean date of budburst. The most and least susceptible half-sib‘families’evaluated were the first and last to flush, respectively. Differences in herbivory for trees in two families with similar phenologies were partially due to oviposition preference.
• 3 Oviposition and larval survivorship were highest on trees in the most susceptible families. Although egg hatch was more closely synchronized with budburst in warm than in cool springs, between tree differences in the time of budburst were consistent over years.