Crude protein content of pollen from the main botanical species used by honeybees in Uruguay

Abstract

Nutritional value of pollen from floral resources utilized by honeybees is very important for beekeeping, fundamentally in areas were modern agriculture causes reduction in biodiversity. Crude protein content of pollen was determined for 25 floral species frequently visited by honeybees. The values found ranged from 14,5 to 41,5%, and most species had pollen with more than 20% protein, minimum accepted value for proper nutrition of bees. In 10 of the 12 species in which more than one sample was examined it was found that the amount of protein does not vary significantly between regions and periods of the year. In species widely exploited by honeybees such as lotus, red clover, white clover, borage and radish, pollen presented more than 30% crude protein. Pollen of Eucalyptus grandis in a plantations had between 28 and 32% protein throughout the flowering period, although in the end it fell to just 18%. The value found for Eucalyptus spp. pollen in the fall was approximately 28%. Only in pollen of «carqueja» and willows it was found less than 20% crude protein. These results indicate that in Uruguay honeybees should not have protein deficiency in their diet when there is a supply of pollen from different botanical species.