Phenology Is an Important Driver of Hawkmoth–Flower Interactions in a Megadiverse Mountain Area in Brazil

Hawkmoths and flowers exhibit striking examples of morphological specialisation, yet how these interactions are structured by different processes within communities still need to be better understood. In this study, we investigated the interactions between hawkmoths and flowers in the megadiverse, open-vegetation landscape of the Brazilian Campos Rupestres. Using a zoocentric approach based on pollen loads found on hawkmoth bodies, we assessed their interactions at the community-level. Our results revealed a modular network, with both hawkmoths and flowering plants organised into modules containing species with dissimilar phenologies. This temporal segregation suggests a staggering pattern of resource use across the year. Hawkmoth proboscis length, however, did not show any pattern regarding module composition. Furthermore, phenology better predicted interaction frequencies than abundances in the network. Therefore, phenology seems to be a primary driver of interaction in this open vegetation seasonal ecosystem. This study represents the first attempt to unravel the organisation of hawkmoth-flower interactions at a community level in this ancient and megadiverse Brazilian ecosystem, and underscore the importance of phenology/seasonality as an important process determining interactions between flowers and long distance flying pollinators capable of connecting isolated plant populations across the landscape.