Environmental Entomology (2018) 47, 1024-1029

Külli Hiiesaar, Tanel Kaart, Ingrid H. Williams, Anne Luik, Luule Metspalu, Angela Ploomi, Eha Kruus, Katrin Jõgar and Marika Mänd (2018)
Dynamics of supercooling ability and cold tolerance of the alder beetle (Coleoptera: Chrysomelidae)
Environmental Entomology 47 (4), 1024-1029
Abstract: Agelastica alni L. (Coleoptera: Chrysomelidae) is a common beetle pest of alder trees (Alnus incana L.) in forests and parks across Estonia. The supercooling ability and capacity to survive low temperature exposure changes temporally. Relatively high unimodal supercooling point (SCP) levels (with a mean value of -6 to -8°C) were characteristic of the beetles in September during their diapause induction period, in April when the beetles had terminated their diapause development and in May when they started to reproduce. During their deep diapause period the SCPs of beetles had a bimodal distribution. Some beetles decreased their SCPs to -14 to -19°C while others retained a high SCP value of -6 to -8°C. Most vulnerable to low temperature were overwintered active beetles in May; after 1 h exposure their LTemp₅₀ (median lethal temperature) was -6.3°C. In September with the onset of diapause tolerance of beetles started to increase, LTemp₅₀ = -7.7°C. Beetles were most cold tolerant during their deep diapause period with LTemp₅₀ < -12.0°C. A. alni beetles use one of two different strategies for overwintering, some are freeze-tolerant while others are freeze-avoidant. The freeze-avoidant beetles with low SCP (-12 to -15°C) acquired greater cold tolerance than those with higher SCP (-6 to -8°C), with LTemp₅₀ = -13.7°C and LTemp₅₀ = -11°C, respectively.
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Link to article at publishers website
Database assignments for author(s): Külli Hiiesaar, Eha Kruus, Luule Metspalu, Angela Ploomi, Katrin Jõgar

Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution
environment - cropping system/rotation

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Agelastica alni	Alder (Alnus)	Estonia