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Does relaxed predation drive phenotypic divergence among insular populations?

Runemark, Anna LU ; Brydegaard, Mikkel LU and Svensson, Erik LU (2014) In Journal of Evolutionary Biology 27(8). p.1676-1690
Abstract
The evolution of striking phenotypes on islands is a well-known phenomenon, and there has been a long-standing debate on the patterns of body size evolution on islands. The ecological causes driving divergence in insular populations are, however, poorly understood. Reduced predator fauna is expected to lower escape propensity, increase body size and relax selection for crypsis in small-bodied, insular prey species. Here, we investigated whether escape behaviour, body size and dorsal coloration have diverged as predicted under predation release in spatially replicated islet and mainland populations of the lizard species Podarcis gaigeae. We show that islet lizards escape approaching observers at shorter distances and are larger than... (More)
The evolution of striking phenotypes on islands is a well-known phenomenon, and there has been a long-standing debate on the patterns of body size evolution on islands. The ecological causes driving divergence in insular populations are, however, poorly understood. Reduced predator fauna is expected to lower escape propensity, increase body size and relax selection for crypsis in small-bodied, insular prey species. Here, we investigated whether escape behaviour, body size and dorsal coloration have diverged as predicted under predation release in spatially replicated islet and mainland populations of the lizard species Podarcis gaigeae. We show that islet lizards escape approaching observers at shorter distances and are larger than mainland lizards. Additionally, we found evidence for larger between-population variation in body size among the islet populations than mainland populations. Moreover, islet populations are significantly more divergent in dorsal coloration and match their respective habitats poorer than mainland lizards. These results strongly suggest that predation release on islets has driven population divergence in phenotypic and behavioural traits and that selective release has affected both trait means and variances. Relaxed predation pressure is therefore likely to be one of the major ecological factors driving body size divergence on these islands. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Evolutionary Biology
volume
27
issue
8
pages
1676 - 1690
publisher
John Wiley & Sons
external identifiers
  • pmid:24890841
  • wos:000339713100017
  • scopus:84904413388
ISSN
1420-9101
DOI
10.1111/jeb.12421
project
BECC
language
English
LU publication?
yes
id
f0a8fd50-4a85-443c-a22e-f41e9a9c32ae (old id 4529357)
date added to LUP
2014-08-12 11:29:21
date last changed
2017-04-09 03:14:12
@article{f0a8fd50-4a85-443c-a22e-f41e9a9c32ae,
  abstract     = {The evolution of striking phenotypes on islands is a well-known phenomenon, and there has been a long-standing debate on the patterns of body size evolution on islands. The ecological causes driving divergence in insular populations are, however, poorly understood. Reduced predator fauna is expected to lower escape propensity, increase body size and relax selection for crypsis in small-bodied, insular prey species. Here, we investigated whether escape behaviour, body size and dorsal coloration have diverged as predicted under predation release in spatially replicated islet and mainland populations of the lizard species Podarcis gaigeae. We show that islet lizards escape approaching observers at shorter distances and are larger than mainland lizards. Additionally, we found evidence for larger between-population variation in body size among the islet populations than mainland populations. Moreover, islet populations are significantly more divergent in dorsal coloration and match their respective habitats poorer than mainland lizards. These results strongly suggest that predation release on islets has driven population divergence in phenotypic and behavioural traits and that selective release has affected both trait means and variances. Relaxed predation pressure is therefore likely to be one of the major ecological factors driving body size divergence on these islands.},
  author       = {Runemark, Anna and Brydegaard, Mikkel and Svensson, Erik},
  issn         = {1420-9101},
  language     = {eng},
  number       = {8},
  pages        = {1676--1690},
  publisher    = {John Wiley & Sons},
  series       = {Journal of Evolutionary Biology},
  title        = {Does relaxed predation drive phenotypic divergence among insular populations?},
  url          = {http://dx.doi.org/10.1111/jeb.12421},
  volume       = {27},
  year         = {2014},
}