CAUSES OF VARIATION IN BIOTIC INTERACTION STRENGTH AND PHENOTYPIC SELECTION ALONG AN ALTITUDINAL GRADIENT
Understanding the causes of variation in biotic interaction strength and phenotypic selection remains one of the outstanding goals of evolutionary ecology. Here we examine the variation in strength of interactions between two seed predators, common crossbills (Loxia curvirostra) and European red squ...
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Published in | Evolution Vol. 68; no. 6; pp. 1710 - 1721 |
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Main Authors | , |
Format | Journal Article |
Language | English |
Published |
United States
Blackwell Publishing Ltd
01.06.2014
Wiley Subscription Services, Inc Oxford University Press |
Subjects | |
Online Access | Get full text |
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Summary: | Understanding the causes of variation in biotic interaction strength and phenotypic selection remains one of the outstanding goals of evolutionary ecology. Here we examine the variation in strength of interactions between two seed predators, common crossbills (Loxia curvirostra) and European red squirrels (Sciurus vulgaris), and mountain pine (Pinus uncinata) at and below tree limit in the Pyrenees, and how this translates into phenotypic selection. Seed predation by crossbills increased whereas seed predation by squirrels decreased with increasing elevation and as the canopy became more open. Overall, seed predation by crossbills averaged about twice that by squirrels, and the intensity of selection exerted by crossbills averaged between 2.6 and 7.5 times greater than by squirrels. The higher levels of seed predation by crossbills than squirrels were related to the relatively open nature of most of the forests, and the higher intensity of selection exerted by crossbills resulted from their higher levels of seed predation. However, most of the differences in selection intensity between crossbills and squirrels were the result of habitat features having a greater effect on the foraging behavior of squirrels than of crossbills, causing selection to be much lower for squirrels than for crossbills. |
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Bibliography: | Robert Berry Chair Endowment ArticleID:EVO12394 istex:2A02B8FC64D737BA9CB922D3259563585CD66F58 ark:/67375/WNG-S6C4WRJ2-V ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0014-3820 1558-5646 |
DOI: | 10.1111/evo.12394 |