PMCCPMCCPMCC

Search tips
Search criteria 

Advanced

 
Logo of procbhomepageaboutsubmitalertseditorial board
 
Proc Biol Sci. May 7, 2004; 271(1542): 893–901.
PMCID: PMC1691675
The herring gull complex is not a ring species.
Dorit Liebers, Peter de Knijff, and Andreas J. Helbig
Institute of Zoology, University of Greifswald, Vogelwarte Hiddensee, 18565 Kloster, Germany.
Under what circumstances speciation in sexually reproducing animals can occur without geographical disjunction is still controversial. According to the ring-species model, a reproductive barrier may arise through 'isolation by distance' when peripheral populations of a species meet after expanding around some uninhabitable barrier. The classical example of this kind of speciation is the herring gull (Larus argentatus) complex, with a circumpolar distribution in the Northern Hemisphere. Based on mitochondrial DNA variation among 21 gull taxa, we show that members of this complex differentiated largely in allopatry following multiple vicariance and long-distance-colonization events, not primarily through isolation by distance. Reproductive isolation evolved more rapidly between some lineages than between others, irrespective of their genetic distance. Extant taxa are the result of divergent as well as reticulate evolution between two ancestral lineages originally separated in a North Atlantic refugium and a continental Eurasian refugium, respectively. Continental birds expanded along the entire north Eurasian coast and via Beringia into North America. Contrary to the ring-species model, we find no genetic evidence for a closure of the circumpolar ring through colonization of Europe by North American herring gulls. However, closure of the ring in the opposite direction may be imminent, with lesser black-backed gulls about to colonize North America.
Supplementary Material
Supplementary data file
Articles from Proceedings of the Royal Society B: Biological Sciences are provided here courtesy of
The Royal Society