The current disjunction between South American rainforests was caused by changes on the vegetation which were guided by changes on the Earth´s climate since middle Tertiary (23 Mybp). This disjunction was expedited during glacial events in Pleistocene (1.6 Mybp) which resulted on the increase of the aridity in the tropical portion of South America. These events led to the modification of the biota located in the interior of Brazil, which culminated on the recurring establishment of refuges during these ice ages and a wide fragmentation inside populations adapted to the rainforests. This change created a huge geographical barrier possibly responsible for the variation found in many groups and the effects of these alterations might be estimated through phylogeographic analyses. Using the social wasps Angiopolybia pallens (rainforest dependent) and Synoeca surinama (rainforest not dependent) as models, we intend to estimate the genetic effects of the Cenozoic climatic-vegetational reversions in populations living in dry and wet tropical forests of South America. Through sequencing of specific nuclear and mitochondrial genes from specimens obtained in many populations of the two species, we will estimate the genetic diversity and the relation of this diversity with the geographical area. This will allow us to infer which period of history these changes appeared to correlate them with both known historical events and processes which could be involved on the current pattern of geographic distribution of genetic variability of these species.
News published in Agência FAPESP Newsletter about the scholarship: