Demographic Structure and Evolutionary History ofDrosophila ornatifrons(Diptera, Drosophilidae) from Atlantic Forest of Southern Brazil

Abstract

Drosoph1la ornatifrons of the guarani group (Diptera: Drosophilidae) is found mainly in humid areas of the Atlantic Forest biome, especially in the southern region of Brazil. Historical and contemporary fragmentation events influenced species diversity and distribution in this biome, although the role of paleoclimatic and paleogeographic events remain to be verified. The objective of the present study was to evaluate the demographic structure of D. ornatifrons from collection sites that are remnants of Atlantic Forest in southern Brazil, in order to contribute to the understanding of the processes that affected the patterns of genetic variability in this species. To achieve this goal, we sequenced 51 individuals from nine localities and 64 individuals from six localities for the mitochondrial genes Cytochrome Oxidase I and II, respectively. Our results indicate that D. ornatifrons may have experienced a demographic expansion event from the southernmost locations of its distribution, most likely from those located next to the coast and in fragments of Atlantic Forest inserted in the Pampa biome (South 2 group), towards the interior (South 1 group). This expansion probably started after the last glacial maximum, between 20,000 and 18,000 years ago, and was intensified near the Pleistocene-Holocene transition, around 12,000 years ago, when temperature started to rise. In this work we discuss how the haplotypes found barriers to gene flow and dispersal, influenced by the biogeographic pattern of Atlantic Forest.

Unveiling the Mycodrosophila projectans (Diptera, Drosophilidae) species complex: Insights into the evolution of three Neotropical cryptic and syntopic species

“…The influence of precipitation on the modelling strategies further supported the interference of the climatic oscillations of the Quaternary in the population dynamics of these species, since this period is characterized by alternating periods of dry and wet conditions in the Southern Hemisphere [ 97 , 98 ]. These results are also concordant with phylogeographic studies performed with other Brazilian drosophilids, which also showed signals of population expansion dated to the Pleistocene [ 99 – 101 ]. This general pattern suggests that several drosophilid species have been subject to demographic oscillations during the glacial–interglacial cycles of this Epoch [ 99 , 102 ].…”

Signature of climatic differentiation on mitochondrial DNA of Drosophila sturtevanti

“…The inland Western Central populations seem to diverge from the Eastern Atlantic populations nearly 4,000 ya. America (Hd = 0.554) (Manfrin & Sene, 2006;Franco & Manfrin, 2013;Cenzi de Ré et al, 2014;Gustani et al, 2015;Barrios-Leal et al, 2018a, b).…”