Source/Fonte: ARKive
The results was published August 4 in the Proceedings of the Royal Society B biological research journal.
Field research revealed that field voles (Microtus agrestis) in the outer archipelago of Stockholm are larger and have longer feet than those living on the mainland. The field voles included in the study were of the same descent, for their habitats emerged from the sea approximately 500 to 1000 years ago as a result of land elevation following the melting of the last glaciers. The islands were colonised by field voles that swam there from the mainland.
The researchers measured and weighed field voles in two mainland and six outer archipelago locations between 1983 and 1987. Then they reared descendants of field voles originating from the mainland and from the archipelago in a laboratory for three years. This was to ensure that the phenotypic differences (body size, foot length) were genetically determined and not caused by, for example, variability in food availability or other environmental conditions. The laboratory-reared descendants of insular voles also had large bodies and long feet. The rate of evolutionary change, measured in darwins, was remarkably rapid.
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Read more here/Leia mais aqui: Science Daily
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Phenotypic evolution of dispersal-enhancing traits in insular voles
Anders Forsman1,*, Juha Merilä2 and Torbjörn Ebenhard3
-Author Affiliations
1School of Natural Sciences, Linnaeus University, 391 82 Kalmar, Sweden
2Ecological Genetics Research Unit, Department of Biosciences, University of Helsinki, PO Box 65, Helsinki 00014, Finland
3Swedish Biodiversity Centre, Box 7007, 750 07 Uppsala, Sweden
*Author for correspondence (anders.forsman@lnu.se).
Abstract
Evolutionary theory predicts that in metapopulations subject to rapid extinction–recolonization dynamics, natural selection should favour evolution of traits that enhance dispersal and recolonization ability. Metapopulations of field voles (Microtus agrestis) on islands in the Stockholm archipelago, Sweden, are characterized by frequent local extinction and recolonization of subpopulations. Here, we show that voles on the islands were larger and had longer feet than expected for their body size, compared with voles from the mainland; that body size and size-specific foot length increased with increasing geographical isolation and distance from mainland; and that the differences in body size and size-specific foot length were genetically based. These findings provide rare evidence for relatively recent (less than 1000 years) and rapid (corresponding to 100–250 darwins) evolution of traits facilitating dispersal and recolonization in island metapopulations.
biodiversity dispersal island populations evolution Microtus agrestis
Footnotes
© 2010 The Royal Society
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