CONICET | Buscador de Institutos y Recursos Humanos

Geneticvariability within and between populations is crucial for the evolutionarypotential of the species and is determinate by a dynamic interaction amongevolutionary and demographic processes, such as genetic drift, naturalselection and range expansion. Mitochondrial DNA is the most used molecularmarker to perform intraspecific analyses in several taxa. Within neotropical Melanoplinae,some species displays intraspecific chromosomal variation. Despite several cytogeneticstudies in acridids, there is a lack of information concerning intraspecificmolecular variation. Scotussa cliens is an extensively distributed SouthAmerican Melanoplinae. Recently, we detected a polymorphic centric fusion intheir populations. However, the study of molecular variation has never beenaddressed in this species. Here, we study the variability of mtDNA cytochromeoxidase subunit I (COI) to understand evolutionary and demographic processesthat affected their populations. A total of 82 individuals of S. cliens werecollected from 11 populations spanning Argentina, Uruguay and Paraguay. Weamplified a fragment of 554 base pairs of COI using specific primers. Thisresulted in 35 polymorphic sites which were analyzed at populational andphylogenetic levels. We found 21 haplotypes. The overall haplotype andnucleotide diversity were high: Hd=0.8970, Pi=0.01173. Privatehaplotypes were found in different biogeographic regions. The network showed animportant genetic variation in the northern populations and expansion in the southernones. The northern populations presented the higher frequency of chromosomefusions and were basal in the phylogenetic analyses. Our data suggest that bothhistorical and demographic factors affected the pattern of genetic variabilityin this grasshopper.