Comparative ecology of conifer-feeding spruce budworms (Lepidoptera: Tortricidae)

The comparative ecology of conifer-feeding budworms in the genus Choristoneura Lederer (Lepidoptera: Tortricidae) in Canada is reviewed with emphasis on publications since 1980. Systematics and life history are updated and historical outbreak patterns and their current interpretation summarised. Recent evidence is analysed in the context of ecological interactions among three trophic levels; host plant, budworm herbivore, and natural enemies. The influence of weather and climate are viewed as modulating factors. The population behaviour of budworms is interpreted as the result of tri-trophic interactions that vary at different scales. The result of these multi-scale interactions is that despite shared phylogenetic constraints and common adaptations, different budworm species display different population behaviour because of specific ecological relationships with their respective hosts and natural enemies.