Synchronous phenology of hawkmoths (Sphingidae) and Inga species (Fabaceae–Mimosoideae): implications for the restoration of the Atlantic forest of northeastern Brazil

Biotic and abiotic factors such as resource availability and rainfall may exert influence on the life cycle of several organisms. In this study, we investigated correlations between the phenology of hawkmoths, flowering phenology of Inga Mill. species (Fabaceae–Mimosoideae–Ingeae) and rainfall in one of the largest remnants of Atlantic forest in northeastern Brazil (Coimbra forest with ca. 3500 ha). We carried out monthly hawkmoth inventories and phenological observations of the five most abundant Inga species in Coimbra forest from October 2005 to August 2007. Altogether 39 hawkmoth individuals were collected with light trap or butterfly net, which were ascribed to nine genera and 14 species. With the present study Pachygonidia caliginosa Boisduval (Bombycoidea–Sphingidae–Dilophonotina) is registered for the second time in Brazil, since the species had been previously collected only in the Amazon. The tribe Dilophonotina was the most represented with five species. Animals with short proboscises (14.7–35.0 mm) represented over 69.7% of the sample. Most individuals were collected during the months of low rainfall, the same period of the highest flower abundance of five Inga species. The flowering of Inga vera, I. striata and I. ingoides was positively correlated with hawkmoth abundance. The synchrony of the activity period of these animals in adult phase with certain nectar sources, and the relationship between morphological parameters of hawkmoths and Inga flowers suggest a narrow pollination mutualistic relationship at the study site. Considering the hotspot status of the Atlantic forest due to high fragmentation and habitat loss, as well as the previous local extinction of hawkmoth species in smaller fragments of the studied landscape, our results are relevant for restoration plans not only for the Brazilian Atlantic forest, but for neotropical forests in general, where Inga is native.