Return of the moth: rethinking the effect of climate on insect outbreaks

Abstract: The sudden interruption of recurring larch budmoth (LBM; Zeiraphera diniana or griseana Gn.) outbreaks across the European Alps after 1982 was surprising, because populations had regularly oscillated every 8–9 years for the past 1200 years or more. Although ecophysiological evidence was li...

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Bibliographic Details
Main Authors: Büntgen, Ulf, Liebhold, Andrew, Nievergelt, Daniel, Wermelinger, Beat, Roques, Alain, Reinig, Frederick, Krusic, Paul J., Piermattei, Alma, Egli, Simon, Cherubini, Paolo, Esper, Jan
Format: Text
Language:unknown
Published: Apollo - University of Cambridge Repository 2020
Subjects:
Global Change Ecology–Original Research
European Alps
Dendroecology
Insect outbreaks
North Atlantic Oscillation
Population cycles
Zeiraphera diniana or griseana
North Atlantic
North Atlantic oscillation
Online Access:https://dx.doi.org/10.17863/cam.63039
https://www.repository.cam.ac.uk/handle/1810/315928
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Summary:Abstract: The sudden interruption of recurring larch budmoth (LBM; Zeiraphera diniana or griseana Gn.) outbreaks across the European Alps after 1982 was surprising, because populations had regularly oscillated every 8–9 years for the past 1200 years or more. Although ecophysiological evidence was limited and underlying processes remained uncertain, climate change has been indicated as a possible driver of this disruption. An unexpected, recent return of LBM population peaks in 2017 and 2018 provides insight into this insect’s climate sensitivity. Here, we combine meteorological and dendrochronological data to explore the influence of temperature variation and atmospheric circulation on cyclic LBM outbreaks since the early 1950s. Anomalous cold European winters, associated with a persistent negative phase of the North Atlantic Oscillation, coincide with four consecutive epidemics between 1953 and 1982, and any of three warming-induced mechanisms could explain the system’s failure thereafter: (1) high egg mortality, (2) asynchrony between egg hatch and foliage growth, and (3) upward shifts of outbreak epicentres. In demonstrating that LBM populations continued to oscillate every 8–9 years at sub-outbreak levels, this study emphasizes the relevance of winter temperatures on trophic interactions between insects and their host trees, as well as the importance of separating natural from anthropogenic climate forcing on population behaviour.

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