Environmental Entomology (2013) 42, 957-966

Leah Flaherty, Dan Quiring, Deepa Pureswaran and Jon Sweeney (2013)
Evaluating seasonal variation in bottom-up and top-down forces and their impact on an exotic wood borer, Tetropium fuscum (Coleoptera: Cerambycidae)
Environmental Entomology 42 (5), 957-966
Abstract: It is well understood that forces from multiple trophic levels simultaneously influence herbivore performance, but how the relative strength of these forces vary over space and time is less clear. We evaluated seasonal variation in the impact of bottom-up forces (host condition), top-down forces (natural enemies), and competition on the performance of an exotic wood borer. Tetropium fuscum (F.) (Coleoptera: Cerambycidae) eggs that were either protected or exposed were placed on healthy and stressed red spruce, Picea rubens Sargent, trees at three different times during the natural T. fuscum flight period. We also measured the length of necrotic lesions (i.e., an induced hypersensitive response) that developed in response to attacking T. fuscum. As predicted, T. fuscum performance was usually greater, and induced host defenses lower, on stressed than on healthy trees, but the impact of host condition on T. fuscum performance varied seasonally. Timing of attack was critical, influencing the strength of bottom-up forces and consequently all measures of T. fuscum performance. Survival was reduced when T. fuscum attacked too early (late-May) or too late (late-June), which may result in stabilizing selection for attack time in this species. Parasitism and competition were generally negligible during this study. Our results suggest that timing of attack is critical for this wood borer and that temporal variation in the impact of top-down and bottom-up forces should be considered in other systems.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Jonathan D. Sweeney, Deepa S. Pureswaran

Research topic(s) for pests/diseases/weeds:
population dynamics/ epidemiology
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Tetropium fuscum	Spruce (Picea)