Diversity and composition of tiger moths (Lepidoptera: Arctiidae) in an area of Atlantic Forest in southern Brazil: is the fauna more diverse in the grassland or in the forest?

The Atlantic Forest is considered a biodiversity hotspot for conservation, because its fauna and flora are highly endemic and suffer from loss of natural habitats. This study assessed the composition and diversity of tiger moths (Lepidoptera: Arctiidae) in two floristic formations of the southern Atlantic Forest (grassland and Araucaria forest) and in a transition zone (forest edge). The moths were attracted to UV light reflected onto a white sheet. A total of 3,574 tiger moths were collected, representing 121 species. The rarefaction curves showed that the tiger-moth assemblage collected in the grassland was more diverse than the assemblages from the Araucaria forest and the transition zone. The assemblages in the forest and forest edge resembled each other, whereas the grassland assemblage was distinct. The composition of the tiger-moth assemblages was related to the environmental characteristics [habitat type (grassland, edge, or forest), altitude, temperature, air relative humidity] and the location of the sites. The faunal similarity decreased in response to increasing environmental and geographical distances between the sites. The responsiveness of tiger moths to small-scale variation in environmental and geographical parameters indicates their good potential as environmental indicators.