Inter-Annual Patterns of Butterfly Abundance Are Synchronized in Seasonal Neotropical Forest

Evidence for significant declines in insects makes understanding the temporal dynamics of tropical communities a high priority. Here, we address the role of weather in influencing patterns of variation in butterflies across a steep rainfall gradient in western Ecuador. We address three questions: (1) How do climatic factors, driving seasonal patterns in butterfly communities, change across the climatic gradient? (2) Is weather more important in influencing abundance and richness in more seasonal sites than more aseasonal sites? (3) Do wet versus dry-adapted species show similar patterns of seasonality regardless of the ecosystem? We sampled bait-attracted butterflies at three forest sites for three consecutive years, in total, 7046 individuals of 212 species were recorded. Butterfly communities exhibited conspicuous intra- and inter-annual variation in temporal dynamics of abundance and species richness, with overall abundance likely synchronized across study sites and years in seasonal forests but not in the aseasonal forest. The highest numbers of species and individuals occurred during the wet season across all study sites and years, and indeed, rainfall was significantly positively associated with abundance. In addition, the highest abundance of dry and wet forest species occurred in both seasonal sites during 2012, the year with highest rainfall, whereas wet forest species peaked a year later in the aseasonal forest, following the pattern of the entire community at this site. These results show how temporal patterns of butterflies depend on the ecosystem type and rainfall regime and underline the significance of weather, as a driver of population trends in seasonal forests.