Abstract With current trends in global warming, it has been suggested that spruce budworm outbreaks may spread to northern parts of the boreal forest. However, the major constraints for a northward expansion are the availability of suitable host trees and the insect winter survival capacity.This study aimed to determine the effect of larval feeding on balsam fir, white spruce and black spruce on various spruce budworm life history traits of both the parental and the progeny generations. Results indicated that the weight of the overwintering larval progeny and their winter survival were influenced by host tree species on which larvae of the parental generation fed. White spruce was the most suitable host for the spruce budworm, producing the heaviest pupae and the heaviest overwintering larvae while black spruce was the least suitable, producing the smallest pupae and the smallest overwintering progeny. Overwintering larvae produced by parents that fed on black spruce also suffered higher winter mortality than individuals coming from parents that fed on balsam fir or white spruce.With current trends in global warming, spruce budworm is expected to expand its range to northern boreal forests where black spruce is the dominant tree species. Such northern range expansion might not result in outbreaks if low offspring winter survival on black spruce persist.

中文翻译：

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寄主树种影响云杉芽虫冬季生存

摘要 随着全球变暖的当前趋势，有人认为云杉幼虫爆发可能会蔓延到北方森林的北部。然而，向北扩张的主要限制因素是合适寄主树木的可用性和昆虫越冬生存能力。本研究旨在确定幼虫取食对香脂冷杉、白云杉和黑云杉的各种云杉芽虫生活史特征的影响。无论是父代还是后代。结果表明，越冬幼虫后代的体重及其越冬存活率受亲代幼虫所摄食的寄主树种的影响。白云杉是云杉幼虫最适宜的寄主，产生最重的蛹和最重的越冬幼虫，而黑云杉最不适宜。产生最小的蛹和最小的越冬后代。以黑云杉为食的亲本产生的越冬幼虫的冬季死亡率也高于以香脂冷杉或白云杉为食的亲本的个体。云杉是优势树种。如果黑云杉的后代冬季存活率低，这种北方范围的扩张可能不会导致爆发。预计云杉 budworm 的活动范围将扩大到以黑云杉为主要树种的北寒带森林。如果黑云杉的后代冬季存活率低，这种北方范围的扩张可能不会导致爆发。预计云杉芽虫将其活动范围扩大到以黑云杉为主要树种的北寒带森林。如果黑云杉的后代冬季存活率低，这种北方范围的扩张可能不会导致爆发。