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Data from: Morphological, genetic and chromosomal variation at a small spatial scale within a mosaic hybrid zone of the grasshopper Dichroplus pratensis Bruner (Acrididae)

Citation

Miño, Carolina Isabel; Gardenal, Cristina Noemí; Bidau, Claudio Juan (2010), Data from: Morphological, genetic and chromosomal variation at a small spatial scale within a mosaic hybrid zone of the grasshopper Dichroplus pratensis Bruner (Acrididae), Dryad, Dataset, https://doi.org/10.5061/dryad.7951

Abstract

Hybrid zones are regions where genetically different populations meet and mate, resulting in offspring of mixed characteristics. In organisms with limited dispersal, such as melanopline grasshoppers, hybrid zones can occur at small spatial scales (i. e., < 500 m). We assessed levels of morphological, chromosomal and molecular variability in adult males of the grasshopper Dichroplus pratensis Bruner (N = 137) collected at 12 sites within a mosaic hybrid zone in a heterogeneous environment in Sierra de la Ventana, Argentina. In this hybrid zone, two Robertsonian chromosomal races, polymorphic for different centric fusions, meet (the Northern race at low altitudes and the Southern race at higher altitudes), forming hybrids that show monobrachial homologies during meiosis. High morphometric variation in six traits was revealed among grasshoppers of both sexes, with male body size positively and significantly correlated with increasing altitude. Frequency of Robertsonian fusions characteristic of the Southern race increased significantly with altitude. Moreover, fusion frequencies covaried between samples. Considerable genetic variation was revealed by RAPD markers, with heterozygosity ranging from 0.3477 to 0.3745. Insects from low-altitude and high-altitude populations showed significant genetic differentiation, as indicated by FST values. The proposed model for D. pratensis, involving the generation and maintenance by chromosomal fusions, of gene complexes adaptive in different environments, could explain the observed clinal patterns within the contact zone.

Usage Notes

Location

Argentina
Buenos Aires Province