Pollen resources of the Humid Chaco and its impact on brood development in honey bee colonies

Abstract

Beekeeping in northeastern Argentina has a promising development, partly due to favorable conditions of the region. Pollen is the main source of protein for bees; the nutritional quality and quantity of pollen will determine the strength of the colonies. Protein intake is necessary for larval development and adult survival, and a shortage of this nutrient significantly affects brood production, reducing the number of larvae to maintain the quality of the offspring. The objective of this study is to identify the floral resources of an apiary located in the Humid Chaco, recognize monthly variations, estimate the protein quality of corbicular pollen loads, and establish relationships between pollen collection and the brood chamber dynamics. Sampling was carried out in an apiary in Corrientes during the 2020–2021 beekeeping period. Conventional pollen and chemical analyses were performed, and optical and scanning electron microscopy techniques were applied for observation. A total of 68 taxa corresponding to 40 angiosperm families were recognized, with crude protein content ranging from 9.9% (1.76% N) to 19.3% (3.45% N). The brood area of the colonies showed small fluctuations, which could be explained by the dynamics of the corbicular pollen input. Nevertheless, it remained relatively constant above 50% brood in the chamber, during spring and summer. The study showed a remarkable diversity of native resources used by the bees compared to other production areas. The recorded blooms did not affect the brood area of the hives and although the pollen of the species analyzed had relatively low protein levels, the colonies did not show weakening or death by starvation.