Pollination of rapeseed (Brassica napus) by Africanized honeybees (Hymenoptera: Apidae) on two sowing dates.

In this study, performed in the western part of the state of Paraná, Brazil, two self-fertile hybrid commercial rapeseed genotypes were evaluated for yield components and physiological quality using three pollination tests and spanning two sowing dates. The treatments consisted of combinations of two rapeseed genotypes (Hyola 61 and Hyola 433), three pollination tests (uncovered area, covered area without insects and covered area containing a single colony of Africanized Apis mellifera honeybees) and two sowing dates (May 25th, 2011 and June 25th, 2011). The presence of Africanized honeybees during flowering time increased the productivity of the rapeseed. Losses in the productivity of the hybrids caused by weather conditions unfavorable for rapeseed development were mitigated through cross-pollination performed by the Africanized honeybees. Weather conditions may limit the foraging activity of Africanized honeybees, causing decreased cross-pollination by potential pollinators, especially the Africanized A. mellifera honeybee. The rapeseed hybrids respond differently depending on the sowing date, and the short-cycle Hyola 433 hybrid is the most suitable hybrid for sowing under less favorable weather conditions.

Melliferous flora and pollen characterization of honey samples of Apis mellifera L., 1758 in apiaries in the counties of Ubiratã and Nova Aurora, PR.

The aim of this study was to carry out a survey of the flora with potential for beekeeping in the counties of Ubiratã and Nova Aurora-PR through the collection of plants and pollen analyses in honey samples collected monthly. 208 species of plants were recorded, distributed in 66 families. The families that showed the major richness of pollen types were: Asteraceae, Myrtaceae and Solanaceae. Approximately 80 pollen types were found in honey samples, most of them were characterized as heterofloral. Cultivated plants, such as Glycine max (soybean) and Eucalyptus spp., were representative in some months of the year. Exotic species, such as Ricinus communis and Melia azedarach, were also frequent. However, over than 50% of the pollen types belong to native species of the region, such as Schinus terebinthifolius, Baccharis spp. Alchornea triplinervia, Parapiptadenia rigida, Hexaclamys edulis, Zanthoxylum sp. and Serjania spp., indicating the importance of the native vegetation for the survival of the colonies.

Physicochemical characteristics and pollen spectra of organic and non-organic honey samples of Apis mellifera L.

The aim of this research was to analyze and compare 17 honey samples, 11 organic and six non-organic Apis mellifera honey. The samples were analyzed concerning moisture, hydroxymethylfurfural, diastase index, water activity, color, total sugar, reducing sugar, sucrose, ash, viscosity, electrical conductivity, pH, acidity, and formol index. With the exception of acidity, reducing sugar and diastase index, the averages of other parameters were different between the two groups. All samples of organic honey presented moisture values between 23.50 and 24.40%. Among the nonorganic honey samples, two presented apparent sucrose amount upper the maximum limit established by the Brazilian Legislation. According to the quantitative analysis of pollen sediments in the honey samples and frequency of pollen types in 17 honey samples, 41.20% were classified as unifioral, and the remainder as polifioral.