Evolutionary Genetics of Zaprionus. II. Mitochondrial DNA and chromosomal variation of the invasive drosophilidZaprionus indianusin Egypt

Abstract

Zaprionus indianus is an Afrotropical drosophilid species that has expanded its geographical range in the Palearctic region and the Americas during the second half of the last century. It has invaded Egypt within the past two decades from East Africa or Asia and became a dominant species in the drosophilid fauna therein, but the exact date of introduction and source of the propagule remain unknown. Here, we investigate the genetic structure of eight geographical populations within and around the Nile Delta using mitochondrial DNA sequences of the cox2 gene and chromosomal inversion polymorphism. A very low level of genetic variability was detected for both markers, mainly attributed to the introduction bottleneck. Nonetheless, both indicate a significant population structure, with a southeastern-northwestern cline. Demographic history analysis suggested northwestern populations to be younger (expanding in ca. 1992) than southeastern ones (expanding in ca. 1985). The In(II)A polymorphism was only observed in the northwestern population, but one-year interval analysis of the Alexandria population revealed the lack of seasonal fluctuation and a trend toward the loss of the polymorphism. Based on these data and faunistic records, we propose a multiple introduction scenario for Z. indianus in Egypt-according to which a first wave in the early 1980s from Sudan through normal northward range expansion or fruit trade, and a second wave in the early 1990s from Asia via fruit trade. We also suggest, from ecological observations, fruit trade data and known adaptive versatility of Z. indianus, date palm, the dominant fruit in Egypt and in the oases where Z. indianus predominates, to play a major role in the spread of the species in the Middle East.

Genetic variability among natural populations of Zaprionus indianus (Drosophilidae) in the States of São Paulo and Minas Gerais, Brazil

“…Based on our data, the two groups of flies demonstrate signs of an incipient selection process, which may subsequently lead to a cline, as Alves and Bélo (2002) described for a nearby region, when they examined Musca domestica populations. Similar results had been observed in Egypt populations, based on mitochondrial DNA and chromosomal inversion polymorphism, despite the low genetic variability that was found (Yassin et al, 2009).…”

“…In general, low variability has been detected in American populations of Z. indianus samples in comparisons of isofemale lines from African and American populations (David et al, 2006) and in studies of mitochondrial DNA (Yassin et al, 2009) from Egyptian samples. Mattos-Machado et al (2005) reported low variability in Brazilian populations compared to African and Asiatic samples, based on allozyme analyses.…”

“…In 2002 it was identified in Egypt, and it has became a dominant species in the drosophilid fauna in that country (Yassin et al, 2009). Based on studies of populations from Asia, Africa and South America, using mitochondrial DNA haplotypes of CO-I and CO-II genes, there are two phylogenetic lineages (phylads); phylad I includes some of the African populations and phylad II includes the Atlantic populations, including South and North America and also Madeira, suggesting that during its passage from endemism to cosmopolitanism, Z. indianus went through two independent radiations (Yassin et al, 2008).…”

Rapid response to abiotic and biotic factors controls population growth of two invasive drosophilids (Diptera) in the Brazilian Savanna

“…Reinforcing the arguments presented above, a higher predictability of the biology and dynamics of D. simulans, compared with Z. indianus, has been reported in worldwide studies (e.g. Karan et al 2000;Gibert et al 2004;David et al 2006;Yassin et al 2009;Commar et al 2012;van Heerwaarden et al 2012).…”

“…This study reinforces previous observations that invasion dynamics depend on the interactions between the traits of invasive species (e.g., life-history and phenotypic plasticity) and the characteristics of the invaded environment. We conclude that models built on complex hierarchical relationships involving climatic conditions, morphological traits and demography explain, to a large extent, the variation in population growth rates of two of the most successful drosophilid invaders in the world: D. simulans and Z. indianus (David and Tsacas 1981;Vilela 1999;Tidon et al 2003;van der Linde et al 2006;Brake and Bächli 2008;Chaves and Tidon 2008;Yassin et al 2009;Mata et al 2010;Commar et al 2012).…”