Guarana (Paullinia cupana var. sorbilis (Mart.) Ducke, Sapindaceae family) is an important and traditional crop of significant economic and social importance in the Amazon region. It is a Brazilian native plant, cultivated by largeand small-scale producers (Embrapa 2005). Its fruits are dehiscent capsules that contain one or three dark brown seeds, with 2.3 to 5 % caffeine. The seeds need to be processed to obtain the powder, syrup, or extract (Angelo et al. 2008), which is used in food, beverage, and pharmaceutical products worldwide. The guarana plant is a monoecious species, with male and female flowers opening at different times (dichogamy) on the same plant (see Supplementary Material ESM1). Several studies have been conducted since the 1970s on the pollinators and floral biology of the guarana plant (Schultz and Valois 1974; Gondim 1978; Carranza et al. 1981; Erickson et al. 1984; Escobar et al. 1984; Ferreira 2003). The flowering period of P. cupana var. sorbilis varies yearly and appears to be related to rainfall patterns (Erickson et al. 1984; Escobar et al. 1984). Generally, the flowering period in the Amazon region begins in late July and ends in November when there is less rainfall. There is a gap in observations on floral visitors between 2 a.m. (at the beginning of anthesis) and 6 a.m., the time when observations began in previous studies by Schultz and Valois (1974), Gondim (1978), Escobar et al. (1984), and Ferreira (2003). According to these authors, the most effective pollinator species, based on flower observations, are the stingless bees of the genus Melipona. This preliminary study aims to answer two fundamental questions regarding the pollination ecology of P. cupana var. sorbilis as follows: (1) are there nocturnal/crepuscular flower visitors? and, if there are, (2) who are these visitors/pollinators? To evaluate the occurrence of floral visitors from the beginning of anthesis, which begins at 2 a.m., surveys were conducted between 2 and 9 a.m. for 8 days, totaling 64 h of sampling. All the censuses/surveys were conducted on clear nights during all moon phases, on nonconsecutive days. Preliminary surveys to collect and identify nocturnal and crepuscular species were made in experimental and commercial fields of flowering guarana in the counties of Manaus (21 and 29/08/2011) and Maues (28 and 29/10/2011), respectively. Additional samples, to quantify (census) the nocturnal, crepuscular, and diurnal visitors, were collected in Manaus (04, 12, 19, and 26/09/2012). Sunrise occurred from 5:37 to 6:07 a.m. during the study. Surveys were made every 30 min and each lasted 10 min. During each survey, the researcher walked slowly along the rows of guarana plants, counting the number of each type of bee (nocturnal, crepuscular, and diurnal) on the flowers in an area of 1 ha, which was surrounded by native vegetation. Due to easy recognition, the bee types were only counted as nocturnal (Megalopta spp.), crepuscular (Ptiloglossa sp.), or diurnal (all the other bees). Sampling was done using entomological nets. The flower visitors were observed and voucher specimens of the insects/bees were collected (authorization number 32357-1 MMA/ICMBio) and Electronic supplementary material The online version of this article (doi:10.1007/s13592-014-0304-3) contains supplementary material, which is available to authorized users.
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Dec 8, 2020
Juan D Urdampilleta + 2
Open Access