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Bottom-up factors contribute to large-scale synchrony in spruce budworm populations

Summary

Published in Canadian Journal of Forest Research 48(3): 277-284. https://doi.org/10.1139/cjfr-2017-0051

Understanding the mechanisms that cause large-scale synchrony in insect population dynamics might yield key insights for predicting potential outbreak occurrence. Here, we evaluated which environmental factors best explain synchronous population fluctuations in the spruce budworm (Choristoneura fumiferana Clem.) (SBW), a major defoliator of coniferous forests in North America. SBW population levels were assessed with pheromone traps during the 1986–2014 period across a 625 000km2 territory located in the province of Québec (Canada). The populations were characterized by abundance fluctuations that were often synchronized across the whole study area. Interannual population fluctuations were correlated with host tree cone production (a source of food) and high May temperatures, suggesting that synchrony was influenced by food availability and phenological mismatch during shoot development. Cone production was itself correlated with low precipitation during the previous summer. This study indicates that bottom-up trophic factors can drive spatiotemporal synchrony in insect populations and contribute to explain important and sustained population increases during some years. We also suggest that several biological processes, all influenced by weather, are likely to interact to explain population synchrony during the different phases of the approximately 35 year SBW outbreak cycle, complicating the prediction of climate change effects on this insect.

Sector(s): 

Forests

Categorie(s): 

Scientific Article

Theme(s): 

Forest Ecology, Forestry Research, Forests, Tree insects and diseases

Departmental author(s): 

Bouchard, Mathieu

Author(s)

BOUCHARD, Mathieu, Jacques RÉGNIÈRE and Pierre THERRIEN

Year of publication :

2018

Format :

PDF available upon request

Keywords :

tordeuse des bourgeons de l’épinette, synchronisme des populations, années semencières, forêts boréales, phénologie, écologie forestière, insectes et maladies, article scientifique de recherche forestière, forest ecology, spruce budworm, population synchrony, mast years, boreal forests, phenology

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