Department of Physics, Chemistry and Biology (IFM)

A clear difference was found in Nymphalidae assemblages between gaps and understory. From the 82 species captured, 39% were found only in gaps, while 13.4% were restricted to the understory. Similar results have been found in Bornean rainforests (Hill & Hamer, 2004; Hamer et al., 2003)) and in Ecuador (DeVries et al., 1999; DeVries & Walla, 2001). However, an almost equal amount of individuals were found in gaps and in the understory. Estimated number of species was also higher in the gaps (119.05) compared to understory (74.2). A potential bias is that the traps sampled only the ground level but as ripe fruits fall to the ground the majority of the fruit feeding species are likely to be found at that level (Hill et al., 2001).

The number of species increased quickly during the first sampling weeks, and leveled off as the areas were more completely sampled. However, the species accumulation curve did not reach an asymptote indicating that more species would have been found with an increased sampling period. Many species are seasonal (DeVries, 1999, 2001) and show a peak of abundance during a specific period only. For example, Panacea prola appeared first at week seven, and then was the predominant species in both habitats (52.34% in gaps and 68.86% in understory) from week 11 until the end of the study. Studies in Yasuni National Park, in Ecuadorian Amazonia over 13 months showed that composition and structure of butterfly assemblages varied significant during the survey with a constant replacement of species throughout the year (Checa et al., 2009).

The clear pattern observed on the distribution of the species between the gaps and understory indicated that species were associated with different habitats. According to the PCA and pRDA scores, the species Pyrrhogyra amphiro, Archeoprepona demophon, Morpho helenor, Adelpha iphiclus, and Memphis basiles showed the strongest association with gaps, whereas, Tigridia acesta, Nessea obrinius, Catoblepia berecynthia, Ca. xantus and Pseudobedis valentina show an association with the understory. The light level was also an important factor for the butterfly assemblages and was, as expected, higher in the gaps. The species associated with the gaps were also the ones that were favored of a high amount of light, unlike the species associated with the understory. However, although gaps, understory and light are shown to be important explanatory variables, the analyses show that there are also other factors driving the repartition of the species.