Phylogeography, population structure and phenotypic variation in the wing dimorphic grasshopper Dichroplus vittatus (Orthoptera: Acrididae)

NATALIA ROSETTI; MARIA ISABEL REMIS

Lausanne

Congreso; XVth ESEB Meeting; 2015

European Society for Evolutionary Biology

Dichroplus vittatus is a South American grasshopper that can display fully-winged (macropterous) or more frequently small-winged (brachypterous) morphs. In order to analyse the genetic and phenotypic differentiation, a fragment of 543 bp of the mitochondrial COI gene was studied and 5 body size related traits were measured in 7 populations from La Pampa and San Luis Provinces. We demonstrated a variable frequency in the percentage of brachypterous individuals, ranging from 100% to 25%. The MANOVA showed significant differences in body size among populations, between sexes with female-biased size and between wing morphs being the brachypterous morph the larger. Molecular studies detected 10 haplotypes from 5 polymorphic sites. Diversity indices were relatively low, particularly in La Pampa populations with higher frequency of macropterous. The AMOVAs using FST showed significant heterogeneity among provinces, between populations and within populations. Haplotype network indicated a moderate component of geographical variation. Demographic indices and mismatch distribution revealed that only one San Luis population fits a recent expansion model. Genetic and phenotypic analysis of studied populations would indicate a relatively short evolutionary history. Consistent with a trade-off between flight capability and reproduction hypothesis, our results suggest that La Pampa Province may be an unstable or less favourable environment for this specie.