The fly that came from the west: Drosophila subobscura in Argentina

FERNÁNDEZ IRIARTE P., J. BALANYA, M. PASCUAL, F. MESTRES, E. HASSON, A. FONTDEVILA & L. SERRA

Uppsala, Sweden

Congreso; 11th Congress of the European Society for Evolutionary Biology; 2007

ESEB

The Palaearctic species Drosophila subobscura has colonized the Pacific coast of Chile since the late 70’s and of North America, from California to British Columbia, since the early 80’s. It was first detected in the Atlantic coast of Argentina in 1984, but the question remained whether the species formed established populations in the area and, if so, whether these populations represented a new colonization event from the Old World.Two samples from Maipú and Mar del Plata, respectively, collected in November 2005 were analyzed for their chromosomal polymorphism, frequency of lethal alleles and microsatellite alleles. The results show that the populations are well established in the area and that all the genetic markers examined present the same characteristics as those of the American populations analyzed previously, rejecting the hypothesis of a new introduction of the species. Moreover, a mild secondary bottleneck is detected when comparing the microsatellite data with those of the Chilean populations, suggesting that the Argentinian populations are the result of the expansion of the species from the colonized areas in the west.