Dalin, P. (2011) Diapause induction and termination in a commonly univoltine leaf beetle (Phratora vulgatissima). Insect Science, 18 (4). pp. 443-450.
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Abstract
The leaf beetle Phratora vulgatissima (Linnaeus 1758) is commonly univoltine in south-central Sweden but may sometimes initiate a partial second generation. The current study was set out to investigate under what abiotic conditions the beetles initiate a second generation. Using climate chamber experiments, the beetles were shown to have a facultative reproductive diapause induced by declining day-length. The critical day-length (CDL) for diapause induction was estimated to be 18 h and 10 min. In the field, first-generation beetles developing to adulthood before August in 2009 became reproductively active and produced a second generation, but most individuals emerged later and were in reproductive diapause. P. vulgatissima overwinter as adults and diapause was shown to be maintained until mid-winter in 2008/2009. The cumulative temperature requirement for oviposition after diapause termination was estimated to be 222 day-degrees with a 5.5°C temperature threshold. Three different day-degree models that were developed to predict the phenology of female oviposition in the spring were validated by comparing model results with field data on the timing of oviposition in previous years. The study suggests that P. vulgatissima may initiate a second generation in Sweden if development of the first generation is completed before August. Warmer spring and summer temperatures due to ongoing climate change may cause advanced insect phenology and faster completion of insect life-cycles at northern latitudes, which will affect the proportion of insects that initiate a second generation.
| Item Type: | Article |
|---|---|
| Additional Information: | The study was financed by a grant from The Royal Swedish Academy of Forestry and Agriculture (KSLA). Emilia Broberg, Karin Eklund, Anders Eriksson and Anna-Sara Liman are thanked for technical support and help with maintaining beetles and plants. Comments and suggestions from Niklas Bj¨orklund, Johan A. Stenberg and three anonymous referees improved the manuscript. Karin Eklund and Christer Bj¨orkman are acknowledged for providing observational field data. |
| Uncontrolled Keywords: | climate change;diapause;insect pests;population dynamics;seasonal adaptations;voltinism |
| Author Affiliation: | Department of Ecology, Swedish University of Agricultural Sciences, P.O. Box 7044, SE-750 07 Uppsala, Sweden. Tel: +46 18 672383; fax: +46 18 672890 |
| Subjects: | Plant Protection |
| Divisions: | General |
| Depositing User: | Mr Siva Shankar |
| Date Deposited: | 21 May 2012 06:37 |
| Last Modified: | 21 May 2012 06:37 |
| Official URL: | http://dx.doi.org/10.1111/j.1744-7917.2011.01417.x |
| URI: | http://eprints.icrisat.ac.in/id/eprint/5555 |
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