Genotypic variation in yellow autumn leaf colours explains aphid load in silver birch
Article first published online: 30 APR 2012
© 2012 The Authors. New Phytologist © 2012 New Phytologist Trust
Volume 195, Issue 2, pages 461–469, July 2012
How to Cite
Sinkkonen, A., Somerkoski, E., Paaso, U., Holopainen, J. K., Rousi, M. and Mikola, J. (2012), Genotypic variation in yellow autumn leaf colours explains aphid load in silver birch. New Phytologist, 195: 461–469. doi: 10.1111/j.1469-8137.2012.04156.x
- Issue published online: 15 JUN 2012
- Article first published online: 30 APR 2012
- Received: 11 January 2012, Accepted: 20 March 2012
- autumn leaf colours;
- genotypic variation;
- local population;
- plant–herbivore interaction
- •It has been suggested that autumn-migrating insects drive the evolution of autumn leaf colours. However, evidence of genetic variation in autumn leaf colours in natural tree populations and the link between the genetic variation and herbivore abundances has been lacking.
- •Here, we measured the size of the whole aphid community and the development of green–yellow leaf colours in six replicate trees of 19 silver birch (Betula pendula) genotypes at the beginning, in the middle and at the end of autumn colouration. We also calculated the difference between green leaf and leaf litter nitrogen (N) and estimated the changes in phloem sap N loading.
- •Autumn leaf colouration had significant genetic variation. During the last survey, genotypes that expressed the strongest leaf reflectance 2–4 wk earlier had an abundance of egg-laying Euceraphis betulae females. Surprisingly, the aphid community size during the first surveys explained N loss by the litter of different birch genotypes.
- •Our results are the first evidence at the tree intrapopulation genotypic level that autumn-migrating pests have the potential to drive the evolution of autumn leaf colours. They also stress the importance of recognizing the role of late-season tree–insect interactions in the evolution of herbivory resistance.