High-altitude South American grasshoppers: defining biological units when genes, chromosomes and morphology tell different stories.

CONFALONIERI, V.A.; GUZMÁN, N.V.; MINUTOLO, C.; POCCO, M.E.; CIGLIANO, M.M.

Kunming

Congreso; 11th International Congress of Orthopterology; 2013

The Orthopterists' Society

The diversification of high-altitude grasshoppers in South America is a complex process, most probably related to tectonic and orogenic activities, and also to climatic factors. Many new biological units emerged during the late Pliocene and Pleistocene in the Andes Mountain range, and, in some cases, divergence may have occurred toorecentlyto be detected by taxonomic or traditional molecular phylogenetic methods. Orotettix (Melanoplinae) and Trimerotropis (Oedipodinae) are two genera of Acrididae inhabiting high-altitude areas under arid and semiarid conditions in South America. Orotetix is represented by five morphologically differentiated species in Peru, while Trimerotropis is probably composed of at least two South American chromosomally differentiated genetic lineages, which are inconsistentwiththe existing taxonomicclassification. Traditional molecular phylogenetic analyses and multilocus coalescent approaches, combined with the study of morphological and chromosomal characters have revealed a complex scenario of species differentiation for these two genera. Molecular clock inferences suggest that the second Andean uplift and climatic fluctuations during glacial and interglacial periods mainly accounted for the diversification of Orottetix and Trimerotropis, respectively. In the latter, chromosomal rearrangement has undoubtedly played a major role in triggering both speciation processes and adaptation to altitudinal clines along the hillsides. In these studies, the use of multiple sources of variation (genes, chromosomes, morphology) in several individuals and populations has helped to elucidate the complex biogeographic scenario of diversification of both Andean genera.