Distribution of genetic variability in populations of two chromosomal races of Dichroplus pratensis (Melanoplinae, Acrididae) and their hybrid zone

MARINA. B. CHIAPPERO, CHRISTIAN PARISE, DARDO A. MARTI , CLAUDIO J. BIDAU & CRISTINA NOEMI GARDENAL

Journal of Evolutionary Biology

Blackwell Publishing

Lugar: Oxford, UK; Año: 2004 vol. 17 p. 76 - 82

We examined, through allozyme electrophoresis, the genetic structure ofpopulations of the acridid grasshopper Dichroplus pratensis from two chromosomalraces (Northern and Southern) and their hybrid zone in Argentina.No fixed alleles for any particular race were found, although geneticdifferentiation among parental races was significant (h ¼ 0.044, 95% CI:0.004–0.068). Hybrid populations are genetically more similar to the Southernrace (h ¼ 0.008, 95% CI: )0.005–0.018) than to Northern ones (h ¼ 0.018,95% CI: 0.002–0.030). Differential viability or fertility of hybrids, or asymmetryin mating preferences in favour of one particular cross would cause ahigher proportion of matings between hybrid individuals and those from theSouthern race. This would explain the high genetic similarity between thosegroups, in spite of their geographical vicinity with northern race populations.