Beija-flores e recursos florais de Psittacanthus dichroos (Mart.) Mart. (Loranthaceae) em uma área da Mata Atlântica da Paraíba

Abstract

This study investigated the relationship between the guild of hummingbirds and Psittacanthus dichroos species, Loranthaceae, a fragment of Atlantic Forest Guaribas Biological Reserve Mamanguape, Paraiba, Brazil. Phenological data were collected from April 2012 to May 2013. Species of hummingbirds visitors and their foraging behavior, as well as the volume and concentration of nectar in the flowers throughout the day were recorded. Reproductions treatments were performed in the flowers to better understand the reproductive system of the plant and the role of hummingbirds as pollinators. We recorded that the Psittacanthus dichroos flower lasted for a day and your anthesis starting around 4:15 pm. This species produces buds and flowers, fresh fruits and ripe throughout the year, with the exception of April 2013 when it was not found flowers. Its flowering synchrony was low in the months of January and February 2013 and the remaining months of 2012 and 2013 were asynchronous. The average length of the corolla tube was 22.7 mm ± 1.8 (N = 41). There was no significant correlation between the total culmen of hummingbirds and corolla length (rs = 0.22, P ≥ 0.05, N = 41). Five species of hummingbirds were observed visiting the flowers of P. dichroos: Eupetomena macroura (N = 4), Chlorostilbon lucidus (N = 1), Chlorestes notatus (N = 2), Florisuga fusca (N = 1) and more frequently Amazilia fimbriata (N = 137) and Phaethornis ruber (N = 33). Coereba flaveola species (N = 17), Dacnis cayana (N = 11), Tangara cayana (N = 1) and Elaenia sp. (N = 2) were also recorded, totaling 207 visits and 28 agonistic interactions. Amazilia fimbriata was considered the dominant species of hummingbirds. Except for Eupetomena macroura and Florisuga fusca, all species of hummingbirds behaved as legitimate pollinators. The mean nectar volume was 59,40 (± 33,01) and the concentration ranged from 0 to 39%. At the peak of flowering (N = 72) are available 2,6 (± 2.3) kcal daily. The number of visits was directly related to the concentration (R² = 0.915, P <0.05) and volume (R² = 0.8835, P <0.05), since larger amounts of resources can promote greater attraction and increase abundance of hummingbirds looking for these energy requirements. The reproduction tests showed that, despite P. dichroos to be a self-compatible species (ISI> 0.9), also depends on deposition of pollen services. Its main function is to promote to Rebio Guaribas resources to its visitors throughout the year, thus maintaining the momentum and the balance of the ecosystem.