Location: Southern Insect Management Research Unit
Title: Analysis of the population structure of Macrolophus pygmaeus (Rambur) (Heteroptera: miridae) in the palaearctic region using microsatellite markers Authors
|Sanchez, Juan Antonio -|
|La Spina, Michelangelo -|
Submitted to: Ecology and Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 3, 2012
Publication Date: November 10, 2012
Citation: Sanchez, J., La Spina, M., Perera, O.P. 2012. Analysis of the population structure of Macrolophus pygmaeus (Rambur) (Heteroptera: miridae) in the palaearctic region using microsatellite markers. Ecology and Evolution. 2(12):3145-3159. DOI: 10.1002/ece3.420. Interpretive Summary: Nine microsatellite markers were used to study fifteen populations of predatory mirid Macrolophus pygmaeus (Rambur) from Palaearctic region. A significant correlation was found between the number of alleles and heterozygosity (Ho) and the distance of each sample to the easternmost locality (Canary Islands). High population differentiation was observed between samples and statistical analyses indicated three main clusters consisting of populations from Greece and Turkey, Italy and France, and southern Iberia and Canary Islands. The data suggest a reduction of the geographical distribution of the species to the Iberian, Italian and Balkan peninsulas during glaciations, maintenance of high diversity in Iberia and Italy during contraction periods, introgression of the Italian-French lineage in northern Spain, naturally or through trade of M. pygmaeus as a biological control agent, and population bottlenecks in the Balkans.
Technical Abstract: Macrolophus pygmaeus (Rambur) (Heteroptera: Miridae) is widely distributed throughout the Palaearctic region. This current geographical distribution may have been influenced by climate change during the last glaciations and the geographical barriers interfering with the dispersal from southern refuges. The aim of this work was to explain the current geographical distribution of M. pygmaeus by investigating the genetic population structure using nine microsatellite markers. Samples of Macrolophus pygmaeus were collected in 15 localities through its Palaearctic range. A sample from a commercial producer was also analysed. Polymorphism was high (13.9 alleles per locus) with a maximum in southern Spain (68 alleles). Istanbul (Turkey) and Nimes (France) had the lowest (0.266) and the highest (0.592) observed heterozygosity (Ho), respectively. There was an increase in Ho from the Canary Islands to Nimes, and a progressive decrease thereafter. A significant correlation was found between the number of alleles and Ho, and the distance of each sample to the easternmost locality (Canary Islands). Significant linkage disequilibrium was observed in the samples from Turkey. FST (0.004 - 0.334) indicated a high population differentiation, with isolation by distance supported by a strong correlation. Bayesian analyses, PCA and UPGMA pointed to three main clusters: (1) Greece and Turkey, (2) Italy and France and (3) southern Iberia and the Canary Islands. The recent evolutionary history of M. pygmaeus is predicted as follows: (1) the reduction of the geographical distribution of the species to the Iberian, Italian and Balkan peninsulas, and possibly southern France, during glaciations and re-colonization of northern Europe from its southern refuges ; (2) The maintenance of high diversity in Iberia and Italy (and possibly southern France) during contraction periods, and bottlenecks in the Balkans; (3) Introgression of the Italian-French lineage in northern Spain, naturally or through trade.