It´s autumn in the southern hemisphere, but it feels like spring with the appearance of flowers and suddenly quite a few butterflies ("borboletas"), the most common of which seems to be this one...
I managed to identify it as the Mangrove Buckeye (Junonia evarete) thanks to the excellent field guides from fieldmuseum org (http://fm2.fieldmuseum.org/plantguides/guide_pdfs/X016-Iracambi-Butterflies.pdf ). As its name suggests, the Mangrove Buckeye rather likes mangroves, in fact from Florida to southern Brazil it is a bane of attempts to reforest coasts with these trees, the caterpillars stripping young seedlings. It's not just mangroves though, caterpillars eat Gervao (Stachytarpheta cayennensis), also know as "Brazil tea", and Sempre viva (Paepalanthus polyanthus) as well as others.
With this diverse food range it can be found far from the coast and mangroves, from Belo Horizonte in the inland mountainous state of Minas Gerais, to Brasilia, over 700 miles from the sea.
Adult females and males can be easily told apart as the males have blue patches (top) whilst the females are more discrete (above). Both have a fast and fairly erratic flight and reportedly prefer the small flowers found in grassland by roads or recently neglected land, certainly I saw these on flowers amongst long grass.