, Volume 112, Issue 1, pp 245–256

Microevolution in island rodents

  • Oliver R.W. Pergams
  • Mary V. Ashley

DOI: 10.1023/A:1013343923155

Cite this article as:
Pergams, O.R. & Ashley, M.V. Genetica (2001) 112: 245. doi:10.1023/A:1013343923155


We perform a meta-analysis on morphological data from four island rodent populations exhibiting microevolution (>≈ 100 years). Data consisting of incidences of skeletal variants, cranial, and external measurements are from house mice (Mus musculus) on one Welsh and one Scottish island, black rats (Rattus rattus) on two Galapagos islands, and deer mice (Peromyscus maniculatus) on three California Channel islands. We report extremely high rates of microevolution for many traits; 60% of all mensural traits measured changed at a rate of 600 d or greater (max. 2682 d). The proportion of all mensural traits evolving at 600–800 d (23%) was idiosyncratic and departed from an expected negative exponential distribution. We argue that selection, rather than founder events, is largely responsible for the substantial shifts in morphology seen among insular rodents. Examining individual traits, there is a trend towards the nose becoming longer and wider, while the skull becomes shallower, shown by both rats and mice on five different islands. We found a significant correlation between island size and degree of skeletal variant evolution and between island distance from the mainland (or nearest island) and degree of cranial and external character evolution. Thus, microevolution of rodents is greater on smaller and more remote islands.

evolution islands mensural traits microevolution Mus musculus Peromyscus maniculatus Rattus rattus rodents skeletal variants 

Copyright information

© Kluwer Academic Publishers 2001

Authors and Affiliations

  • Oliver R.W. Pergams
    • 1
  • Mary V. Ashley
    • 2
  1. 1.Department of Biological Sciences (M/C 066)University of Illinois at ChicagoChicagoUSA
  2. 2.Department of Biological Sciences (M/C 066)University of Illinois at ChicagoChicagoUSA

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