Changing the main course: strong bat visitation to the ornithophilous mistletoe Psittacanthus robustus (Loranthaceae) in a Neotropical savanna

"The Neotropical genus Psittacanthus comprises mostly specialized ornithophilous mistletoes, with rare exceptions. Psittacanthus robustus is a common ornithophilous species from the South American savannas whose bright yellow flowers secrete copious diluted nectar. Due to a three-day-long anthesis and a short, non-restrictive floral tube, we suggest that the species also serves as a resource for flower-visiting bats. In a Cerrado area in central Brazil, we investigated the usage of the species by bats through systematic bat captures for pollen sampling, its nocturnal nectar secretion dynamics, mating system, and the relative dependence on diurnal and nocturnal pollinators for reproduction. Nine phyllostomid bat species visited P. robustus. Up to 50% of pollen samples from bats contained the species during peak flowering, equating or surpassing the prevalence of chiropterophilous species and representing roughly a third of the floral resources consumed by specialized nectarivores Glossophaga soricina and Anoura caudifer. Flowers actively produced nectar at night with volume and concentration values in the ideal ranges for bat consumption. Nectar is continuously secreted after sunset and accumulates in the absence of visitors. Psittacanthus robustus is self-compatible but seeds are set mostly by diurnal visitors. Nocturnal animals had a low and secondary contribution to plant fitness. This is the second report of bat pollination for the genus Psittacanthus, and the largest assemblage of bat visitors for the family Loranthaceae. Although ornithophilous, P. robustus is an important resource for bats in the Brazilian savanna, potentially representing a mixed or early transitional state toward bat pollination."