Diversification patterns in Scotussae (Orthoptera: Acrididae) genus group

SCATTOLINI, MARÍA CELESTE; CONFALONIERI, VIVIANA; CIGLIANO, MARÍA MARTA

Agadir

Congreso; 13th International Congress of Orthopterology; 2019

IBN ZOHR University of Agadir/ National Center for Control of Desert Locust /Orthopterists? Society

The Scotussae genus group is a diverse clade that inhabits open biomes of Brazil, Bolivia, Paraguay, Uruguay and Argentina, occurring mainly in the Chacoan and Parana dominions of South America. This clade of brachypterous and macropterous species is characterized by the variation in the ovipositor morphology and by complex chromosomal rearrangements. The aim of this study is to apply an integrative biogeographic approach to study the diversification of the group, analysing simultaneously three sources of evidence: diversification time, phylogenetic relations and geographic evolution.Fifty specimens of the Dichoplini tribe were analysed representing all the genera of the Scotussae group and 4 species selected as outgroup. A total evidence phylogenetic analy-sis was performed considering three genetic regions (COI, ND2, H3) combined with mor-phological evidence. Niche similarity tests and the degree of niche overlap were estimated among the species. Ecological niche models were generated assessing the realized ecolog-ical niche and the potential distribution. Phy-logenetic signal between the phylogenetic re-latedness and the niche overlap, the geo-graphic and the environmental distances were analysed. The phylogenetic signal in the envi-ronmental variables and the ancestral range were also evaluated. Our findings suggest that ecology would have played a major role in the diversification of the Scotussae group, since phylogenetic relation-ships have a greater association with envi-ronmental variables than with geographical distances. Within the group, two main clades (Brachypterous / Macropterous) with different diversification patterns were recovered. The diversification of the Scotussae genus group would have occurred during the Pliocene in the Seasonally Dry Tropical Forests (SDTF) open vegetation biome. The geo-historical events that occurred during the last gla-cial-interglacial cycles in the SDTF could have played a predominant role in the allopatric speciation that might have suffered the Bra-chypterous clade. On the other hand, it is con-sidered that the main diversification event within the Macropterous clade could have been sympatric speciation, finding evidence of ecological speciation and cytogenetic barriers.