Influence of floral resources on honey bee colony growth and reproductive swarming patterns in the Sonoran Desert of Arizona.

Abstract

Relationships between patterns of food (nectar and pollen) harvest and honey bee colony growth and reproduction are poorly understood. Research was conducted on the relationships between food harvest and colony growth in the Sonoran desert of Arizona. Annual patterns of resources (pollen harvest rates, pollen protein content, protein influx rates, and nectar harvest) and colony growth and reproduction (brood area, adult population, and reproductive swarm occurrence) for the Tucson area were obtained. Annual patterns were analyzed for periodicity and stability using autocorrelation time series analysis. Each resource pattern was compared to each colony growth pattern using cross-correlation analysis which revealed time lag interval of correlation between the two data sets. The foraging activity of the honey bee colonies was dominated by pollen foraging, with pollen harvested on a year-round basis. Nectar collection was limited to only a few weeks each year. The colony growth patterns all reached their maxima in spring or early summer. The autocorrelation analysis revealed that all data sets exhibited periodic and stable behaviors based on an annual (52 week) cycle. The colony growth data sets were also predictable in magnitude. The cross-correlation analysis revealed that the areas of sealed brood, number of adult bees, and swarm occurrence were more correlated to protein influx than any other food resource parameter. The timing of the greatest nectar harvest occurred just after the peak of swarm occurrence. Colonies fed supplementary pollen diets containing 24.8% or 17.2% protein were compared to non-fed controls. The number, timing, and survival of swarms was monitored. The initiation of queen-cell construction was directly related to protein influx rates exceeding 20 g colony⁻¹ day⁻¹. The 24.8% protein treatment swarmed earlier than the other two treatments. Swarm survival was highest in swarms that issued just prior to the nectar flow. Honey bee colony growth and reproductive swarming patterns in Tucson are directly related to protein influx rates. This response results in swarm production at a time of year when nectar is most abundant, thus aiding long-term swarm survival. Similar relationships between patterns of food harvest and swarming should occur for all temperate honey bee colonies.