Evolutionary history and colonization patterns of the wing dimorphic grasshopper Dichroplus vittatus in two Argentinean biomes

Abstract

Quaternary climate oscillations and modification of the environment by humans have played an important role in shaping species distribution and genetic structure of modern species. Here, population genetic parameters were inferred from the analysis of 168 individuals belonging to 11 populations of the South American grasshopper, Dichroplus vittatus, distributed in two Argentinean Biomes (Grassland and Savanna), by sequencing a 543 bp of the mitochondrial COI gene. Overall, we detected considerable haplotype diversity and low nucleotide diversity. AMOVA analyses showed a significant degree of differentiation among Biomes and between populations. Two major mitochondrial lineages can be distinguished. The haplogroup containing the most common haplotype split 17,000 years BP while the haplogroup including the second most common haplotype has a divergence date of about 11,700 years. Approximate Bayesian Computation (ABC) analyses showed that the palaeodemographic scenario that best fitted our data is consistent with a hypothesis of divergence from an ancestral population and subsequent admixture with Grassland-Savanna (South–North) direction. Our results suggest that populations located in both Biomes would derive from a single ancestral population that colonized the region after the Last Glacial Maximum and Grassland would have a more ancestral origin than Savanna. Further, our results emphasize the importance of human-mediated dispersal in the reconfiguration of genetic diversity of species with potential pest capacity.

Geography, climate and changes in host plants distribution explain patterns of genomic variation within the cactus moth

“…Evidence for admixture was also detected between populations of East and South lineages, both distributed within the Pampean and Monte regions. This area has been reported as a landscape corridor facilitating connectivity between previously separated populations of the grasshopper species D. vittatus inhabiting grassland and savanna biomes (Rosetti et al, 2022). Our results would further emphasize the extensive habitat connectivity between these regions during the Quaternary.…”

“…Climatic changes during the Quaternary promoted complex phylogeographic patterns in many southern South American arthropods, such as the grasshopper Dichroplus vittatus Bruner (Rosetti et al, 2022), the beetle Naupactus cervinus Boheman (Rodriguero et al, 2016), mygalomorph spiders (Calatayud-Mascarell et al, 2022, among other taxa (Bonatelli, Gehara, Carstens, Colli & Moraes, 2022). Similar phylogeographic consequences of climate change over the last 21,000 years have been recently documented for O. bonaerensis , one of the host species for C. cactorum (Köhler, Esser, Font, Souza-Chies & Majure, 2020).…”

“…Evidence for evolutionary consequences of landscape changes promoted by Quaternary climatic dynamics is being increasingly documented in southern South America. The distributional shifts of open vegetation biomes, such as the Chacoan and Pampean domains, have been hypothesized to determine the diversification history of many faunal taxa intimately linked to these habitats (Rodriguero et al, 2016;Rosetti, Krohling & Remis, 2022;Turchetto-Zolet, Pinheiro, Salgueiro & Palma-Silva, 2013).…”

The Phylogeography and Demographic History of the Direct-Developing Coastal Gastropod Haustrum haustorium

“…If uplift events along the Wairarapa Fault were the cause of the phylogeographic break along the south-eastern coast of the North Island, H. haustorium was either well established before these uplifting events or was undisturbed by them. The former is supported by both the shape of the mismatch distribution (Figure 3.1) and the Bayesian Coalescent Skyline plot, which suggests a stable population (Rosetti et al, 2022). 1).…”

“…A bimodal or multimodal distribution of these pairwise differences may indicate a population that has a constant and stable population size (Slatkin and Hudson, 1991). Additionally, a multimodal distribution may suggest ancient subdivision from which stable populations have arisen (Rosetti et al, 2022). A unimodal distribution of pairwise differences suggests that a population has undergone a sudden expansion, typically in response to a bottleneck event.…”