Latitudinal and morphological divergence among three allopatric populations of Rhagoletis cingulata in Eastern America and Northern Mexico.

Abstract

Abstract Geography is often a key factor facilitating population divergence and speciation. Determining the underlying causes of this radiation is fundamental to understanding the emergence of new species as a result of evolutionary processes or reproductive barriers to gene flow between populations, which are caused by the availability of resources and prevailing environmental conditions in different habitats. The objective of this work was to analyse the morphological variations present in three geographically isolated and latitudinally distant populations of flies of the cingulata group. The results provide evidence of a clinal pattern of geographic variation among these populations, as shown by morphometric changes, variations in femur pigmentation and the presence of an apical band or point in the wing patterns among individuals from different populations. These phenotypic differences could be closely related to the phenotypic differences found within the cingulata group and even show a different pattern of adaptive radiation than that of R. pomonella that gave rise to the incipient apple and hawthorn-associated species in the USA.