Estruturação temporal de assembleias de borboletas frugívoras no extremo sul do Brasil: uma avaliação em longo prazo

Abstract

Ecological interactions and geographical gradients are among the most important factors that shape communities structure, determinig their diversity patterns and spatio-temporal distribution. Changes in the latitudinal gradient determines variations in climatic variables, like temperature and precipitation rates, and these variables are important to several organisms, changing their seasonal patterns in activity. Research involving temporal distribution patterns and insect seasonality is still scarce, especially related to long-term assessments in subtropical regions. The aim of this study was to verify seasonality patterns in the structuring of fruit-feeding butterfly assemblages through five years of samples in Restinga forests in the extreme south of Brazil. It is expected that the seasonality, given to temperature changes among seasons, will influences the temporal distribution patterns of fruit-feeding butterfly assemblages, and that the diversity parameters are positively correlated to this variable, registering: (i) greater richness, abundance and diversity of fruit-feeding butterflies in the hottest seasons (summer and spring) and smaller on the coldest ones (autumn and winter); (ii) and that a different species composition be recorded for each season. Data were collected monthly between December 2014 and November 2019. Summer was the season that registered the greatest abundance (N) and richness (S), with N = 1,057 and S = 24, followed by spring (N = 400; S = 20), autumn (N = 376; S = 20) and winter (N = 72; S = 12). Peaks of both parameters occur mainly in January and February, with the lowest values recorded in winter. Surprisingly, spring and winter were the least diverse seasons in the extreme south of Brazil, due to its high dominance. Spring and winter had the same species composition, and the other seasons were different to each other. The patterns of alpha diversity were drive by means of temperature; whereas to the beta diversity, high temperatures and less accumulated precipitation had a positive association with the summer composition; but the interaction between both high rainfall rates and humidity has a negative influence on spring and winter abundance variations. Most indicator species were associated with summer. In the present study, new patterns were presented on the understanding of the temporal distribution and seasonality of the fruit-feeding butterfly assemblages for the subtropical region. The studied region is the southernmost portion studied in South America and presents a more pronounced seasonality than other locations studied in Brazil. Studying and understanding the patterns of temporal distribution of fruit-feeding butterflies is important because it serves as a basis for many other studies. By performing long time series work, we are able to understand more deeply what is going on in the communities, understanding processes that may be generating the observed patterns, in addition to observing fluctuations in these patterns over time and being able to make associations with climatic events, as well as emerging climate change.