DIVERSIFICATION PATTERNS IN SCOTUSSAE (ORTHOPTERA: ACRIDIDAE) GENUS GROUP

SCATTOLINI M. CELESTE; CONFALONIERI V. A.; CIGLIANO MARÍA M.

Agadir

Congreso; 13th International Congress of orthopterology; 2019

Orthopterist´s Society

The Scotussae genus group is a diverse clade thatinhabits open biomes of Brazil, Bolivia, Paraguay,Uruguay and Argentina, occurring mainly in theChacoan and Parana dominions of South America.This clade of brachypterous and macropterousspecies is characterized by the variation inthe ovipositor morphology and by complexchromosomal rearrangements. The aim of thisstudy is to apply an integrative biogeographicapproach to study the diversification of thegroup, analysing simultaneously three sourcesof evidence: diversification time, phylogeneticrelations and geographic evolution.Fifty specimens of the Dichoplini tribe wereanalysed representing all the genera of theScotussae group and 4 species selected asoutgroup. A total evidence phylogenetic analysiswas performed considering three genetic regions(COI, ND2, H3) combined with morphologicalevidence. Niche similarity tests and the degreeof niche overlap were estimated among thespecies. Ecological niche models were generatedassessing the realized ecological niche andthe potential distribution. Phylogenetic signalbetween the phylogenetic relatedness andthe niche overlap, the geographic and theenvironmental distanceswere analysed. The phylogenetic signal in theenvironmental variables and the ancestral rangewere also evaluated.Our findings suggest that ecology would haveplayed a major role in the diversification of theScotussae group, since phylogenetic relationshipshave a greater association withenvironmental variables than with geographicaldistances. Within the group, two main clades(Brachypterous / Macropterous) with differentdiversification patterns were recovered. Thediversification of the Scotussae genus groupwould have occurred during the Pliocene in theSeasonally Dry Tropical Forests (SDTF) openvegetation biome. The geo-historical events thatoccurred during the last glacial-interglacialcycles in the SDTF could have played apredominant role in the allopatric speciation thatmight have suffered the Brachypterous clade. Onthe other hand, it is considered that the maindiversification event within the Macropterousclade could have been sympatric speciation,finding evidence of ecological speciation andcytogenetic barriers.