Regional climate modulates the canopy mosaic of favourable and risky microclimates for insects

Authors

  • SYLVAIN PINCEBOURDE,

    1. Institut de Recherche sur la Biologie de l’Insecte (IRBI, CNRS UMR 6035), Université François Rabelais, Faculté des Sciences et Techniques, 37200 Tours, France; *UMR PIAF INRA-Université Blaise Pascal, Site de Crouelle, 234 avenue du Brézet, 63100 Clermont-Ferrand, France; and †INRA Unité d’Ecophysiologie des Plantes Fourragères, 86600 Lusignan, France
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  • HERVE SINOQUET,

    1. Institut de Recherche sur la Biologie de l’Insecte (IRBI, CNRS UMR 6035), Université François Rabelais, Faculté des Sciences et Techniques, 37200 Tours, France; *UMR PIAF INRA-Université Blaise Pascal, Site de Crouelle, 234 avenue du Brézet, 63100 Clermont-Ferrand, France; and †INRA Unité d’Ecophysiologie des Plantes Fourragères, 86600 Lusignan, France
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  • * DIDIER COMBES,

    1. Institut de Recherche sur la Biologie de l’Insecte (IRBI, CNRS UMR 6035), Université François Rabelais, Faculté des Sciences et Techniques, 37200 Tours, France; *UMR PIAF INRA-Université Blaise Pascal, Site de Crouelle, 234 avenue du Brézet, 63100 Clermont-Ferrand, France; and †INRA Unité d’Ecophysiologie des Plantes Fourragères, 86600 Lusignan, France
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  • JEROME CASAS

    1. Institut de Recherche sur la Biologie de l’Insecte (IRBI, CNRS UMR 6035), Université François Rabelais, Faculté des Sciences et Techniques, 37200 Tours, France; *UMR PIAF INRA-Université Blaise Pascal, Site de Crouelle, 234 avenue du Brézet, 63100 Clermont-Ferrand, France; and †INRA Unité d’Ecophysiologie des Plantes Fourragères, 86600 Lusignan, France
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Errata

This article is corrected by:

  1. Errata: Editors’ Note: Young Author of the Year Award – Elton Prize Nomination Volume 77, Issue 3, 634, Article first published online: 14 April 2008

and present address: Sylvain Pincebourde. University of South Carolina, Department of Biological Sciences, Columbia, SC 29208, USA. E-mail: sylvainp@biol.sc.edu

Summary

  • 1 One major gap in our ability to predict the impacts of climate change is a quantitative analysis of temperatures experienced by organisms under natural conditions. We developed a framework to describe and quantify the impacts of local climate on the mosaic of microclimates and physiological states of insects within tree canopies. This approach was applied to a leaf mining moth feeding on apple leaf tissues.
  • 2 Canopy geometry was explicitly considered by mapping the 3D position and orientation of more than 26 000 leaves in an apple tree. Four published models for canopy radiation interception, energy budget of leaves and mines, body temperature and developmental rate of the leaf miner were integrated. Model predictions were compared with actual microclimate temperatures. The biophysical model accurately predicted temperature within mines at different positions within the tree crown.
  • 3 Field temperature measurements indicated that leaf and mine temperature patterns differ according to the regional climatic conditions (cloudy or sunny) and depending on their location within the canopy. Mines in the sun can be warmer than those in the shade by several degrees and the heterogeneity of mine temperature was incremented by 120%, compared with that of leaf temperature.
  • 4. The integrated model was used to explore the impact of both warm and exceptionally hot climatic conditions recorded during a heat wave on the microclimate heterogeneity at canopy scale. During warm conditions, larvae in sunlight-exposed mines experienced nearly optimal growth conditions compared with those within shaded mines. The developmental rate was increased by almost 50% in the sunny microhabitat compared with the shaded location. Larvae, however, experienced optimal temperatures for their development inside shaded mines during extreme climatic conditions, whereas larvae in exposed mines were overheating, leading to major risks of mortality.
  • 5 Tree canopies act as both magnifiers and reducers of the climatic regime experienced in open air outside canopies. Favourable and risky spots within the canopy do change as a function of the climatic conditions at the regional scale. The shifting nature of the mosaic of suitable and risky habitats may explain the observed uniform distribution of leaf miners within tree canopies.

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