O presente estudo tem como objetivo contribuir para o conhecimento das borboletas frugívoras em diferentes ambientes de um fragmento de Floresta Ombrófila Mista no município de São Francisco de Paula, região Nordeste do Rio Grande do Sul. As amostragens foram realizadas mensalmente entre março de 2008 e fevereiro de 2009 em duas transecções. Em cada transecção foram colocadas oito armadilhas atrativas fermentadas com banana e caldo de cana ao longo de três dias por ocasião amostral. Após um total de 5760 horas de amostragem foram registradas 30 espécies pertencentes a três subfamílias e seis tribos de borboletas frugívoras. Três espécies são novos registros para a Floresta Ombrófila Mista do Rio Grande do Sul: Prepona pylene pylene, Narope cyllastros e Opoptera sulcius, tendo esta última registro publicado para a região sudeste do estado.

Fruit‐feeding butterflies occur in tropical and subtropical forests; however, knowledge of the variations in abundance and structure at the population level under seasonal cycles in temperature is still lacking. Understanding how populations are organised is essential to unveiling the ecological factors that can influence their dynamics. We studied the population biology and natural history of the satyrine Taygetis ypthima Hübner, [1821], which occurs in the Atlantic Rainforest, using capture‐mark‐recapture and behavioural methods. From August 2014 to August 2015, 262 captures (131 males and 131 females) were recorded on 22 sampling occasions, with a sampling effort of 7620 trap‐days and 309 net‐hours. Adults were found year round. The numbers were lowest in summer and peaked in winter, which is unusual for subtropical regions. Females were larger, moved more and exhibited longer residence times compared with males; these patterns were possibly related to behavioural differences between sexes. Territory disputes between males were observed frequently in July–August. The longest‐lived butterfly was 247 days old when the study was terminated. To the best of our knowledge, this is the longest documented longevity for a butterfly in the Neotropics. The age structure of the population varied throughout the year. In winter, when the study started, the whole population was middle‐aged, and by late spring, all butterflies were old. Young individuals appeared beginning in early summer, and then, by early autumn, all were middle‐aged again, suggesting that the population has periods of higher recruitment of butterflies from pupae that came from the same generation. The data obtained here are a basis for future investigations to determine the environmental factors affecting the population dynamics of T. ypthima and to understand the role landscape heterogeneity plays in the maintenance of viable populations.