Spatial Genetic Structure and Mitochondrial DNA Phylogeography of Argentinean Populations of the Grasshopper Dichroplus elongatus

Abstract

Many grasshopper species are considered of agronomical importance because they cause damage to pastures and crops. Comprehension of pest population dynamics requires a clear understanding of the genetic diversity and spatial structure of populations. In this study we report on patterns of genetic variation in the South American grasshopper Dichroplus elongatus which is an agricultural pest of crops and forage grasses of great economic significance in Argentina. We use Direct Amplification of Minisatellite Regions (DAMD) and partial sequences of the cytochrome oxydase 1 (COI) mitochondrial gene to investigate intraspecific structure, demographic history and gene flow patterns in twenty Argentinean populations of this species belonging to different geographic and biogeographic regions. DAMD data suggest that, although genetic drift and migration occur within and between populations, measurable relatedness among neighbouring populations declines with distance and dispersal over distances greater than 200 km is not typical, whereas effective gene flow may occur for populations separated by less than 100 km. Landscape analysis was useful to detect genetic discontinuities associated with environmental heterogeneity reflecting the changing agroecosystem. The COI results indicate the existence of strong genetic differentiation between two groups of populations located at both margins of the Paraná River which became separated during climate oscillations of the Middle Pleistocene, suggesting a significant restriction in effective dispersion mediated by females and large scale geographic differentiation. The number of migrants between populations estimated through mitochondrial and DAMD markers suggest that gene flow is low prompting a non-homogeneous spatial structure and justifying the variation through space. Moreover, the genetic analysis of both markers allows us to conclude that males appear to disperse more than females, reducing the chance of the genetic loss associated with recent anthropogenic fragmentation of the D. elongatus studied range.

Genetic diversity of mango leafhopper, Amritodus atkinsoni (Hemiptera: Cicadellidae) based on mtCOI gene sequences from India

“…Most of the populations shared one or both of the most frequent haplotypes (H2 and H5). When values of haplotype (Hd > 0.5) and nucleotide (p > 0.5%) diversity are high, the population appears to be stable with a relatively long evolutionary history (Rosetti and Remis 2012).…”

“…Except R, this situation is observed for all the populations studied, where haplotype diversity is relatively high and nucleotide diversity relatively low. When both p and Hd values are low, the population has probably undergone a reduction in population size or a recent colonization event (Rosetti and Remis 2012). RJ is characterized by low values in both indices, reflecting recent population colonization.…”

Research Article Genetic assessment of a breeding population of black rhinoceros in Kenya using mitochondrial DNA D-loop sequencing

“…This segment is the most variable part of the mtDNA and evolves five times faster than the rest of the mitochondrial genome. As a result, the mtDNA D-Loop has been used effectively in phylogenetic evaluations (Yacoub and Fathi, 2013), genetic diversity studies (Kawabe et al, 2014;Ashley, Melnick et al, 1990;Zhang et al, 2017) and population structure analysis (Rosetti and Remis, 2012). The results from this study will be helpful in the formulation of genetically driven translocation and supplementation programs.…”

A history of invasion: COI phylogeny of Manila clam Ruditapes philippinarum in Europe

“…Spatial or demographic expansion was estimated through Tajima's D neutrality test (Tajima, 1989) performed using DNAsp 5.0, assessing significance with 1000 permutations (Rossetti and Remis, 2012) and testing data for 4 different subsets: at large scale for the entire R. philippinarum pool, for the European pool, and separately for the Atlantic and for the Adriatic pools.…”