Insetos visitantes florais associados a um guaranazal (Paullinia cupana var. sorbilis (Mart.) Ducke), com notas sobre sua polinização

Abstract

Among the pollinating agents, such as bees stands out through present morphological and behavioral modifications being responsible for the pollination of the most natural and cultivated plant species such as guarana. It is a culture with nocturnal anthesis, but the real pollinators are not defined yet. In this work a community of insect floral visitors and the plants visited by them was studied in an area associated with guaraná cultivation, contributing with information to maintain the pollinators in the area of cultivation in a sustainable way and to elucidate gaps of the pollination of guaraná. The collection of floral visitors was carried out monthly for a year, between June 2016 and May 2017, in a transect of approximately 3.5 Km around guaraná crops. The experiments and tests of floral, reproductive biology and efficiency of the pollinators were carried out on BRS-Maués clones at Embrapa Amazônia Occidental. 3,269 insects were collected from 47 from 59 fertile plant species evaluated along the transect. The collected floral insects belong to 271 species distributed in 38 families of three megadiverse orders, Lepidoptera, Diptera, and Hymenoptera. A total of 2,691 bees were collected from 115 species, with Apidae being the most abundant family (92.6%), followed by Halictidae (5,7%), Megachilidae (0.6%) and Colletidae (1,1%). Spemacoce alata was the species of the plant most used by bees, is an important resource for the community of bees visitors floral over a year. The presence of nectar guides and odor producing glands in pistillate and staminate flowers were evaluated. The guaraná reproductive system was evaluated through hand cross-pollination, natural cross-pollination, and spontaneous self-pollination treatments as well as the efficiency of floral visitors. The period with greater stigmatic receptivity and pollen viability occurs around 9:00 am and period of greater activity of day visitors of guarana. Guaraná plant depends entirely on pollinators, the highest quality and heavier fruits and seeds were formed from pollinations carried out around 5:00 am and 09:00 am. This period corresponds to the greater activity of nocturnal bees, Megalopta spp., and diurnal as Melipona spp. and Apis mellifera scutellata.