Pollen sources for honeybees in Israel: Source, periods of shortage, and influence on population growth

Abstract

The nutritional demands of honeybees are met by two plant-produced components: nectar and pollen, the contents of which vary among floral sources. In Israel, there is an extraordinary richness in plant species, and one of the dominant insect pollinators is the honeybee (Apis mellifera L.). July to February is characterized as a period of low flower abundance for local species in general and for bee forage plants in particular. In this study, we monitored the amount and number of pollen sources collected by honeybees, and where possible also identified the plant source of pollen, in four geographically distinct sites in Israel. We also assessed honeybee colonies (population level, sealed brood area, and pollen and honey stores) and studied the effect of pollen levels on population growth. Our results show that peak pollen-collection times differ according to site. The number of pollen sources from trapped pollen pellets varied during the year, between sites, and between colonies in the same site, and ranged between 5 and 20 plant species per sampling date per site. The most abundant pollen source in each sample comprised between 22 and 94% of the pollen pellets. There were only a few cases in which pollen was collected from fewer than five or more than nine plants in each colony's sample. Thus, colonies seem to specialize in only a small number of species of the available flora. Overall, in all sites, the daily amount of pollen collected was significantly correlated with sealed brood and pollen store areas.

Omega-3 deficiency impairs honey bee learning

“…In a diverse habitat, colonies tend to collect pollen from a variety of sources (24). But in disturbed habitats and extensive agricultural monocultures, the breadth of the diet is reduced (25), and bees may suffer from a deficiency of eFAs.…”

Bee Food: The Chemistry and Nutritional Value of Nectar, Pollen and Mixtures of the Two

“…Diversity in bee diets may be necessary to avoid nutritional deficiencies (Schmidt et al 1995) and to dilute toxins, but need not involve many plant species. Honeybee colonies sampled at various sites in Israel over a year usually collected pollen from 5-9 species at a time (Avni et al 2009). Similar dependence on a few pollen sources was noted by Keller et al (2005), based mainly on Swiss studies, and mixed pollens from five plant species were found to be better than single pollens for maintaining honeybee immune systems (Alaux et al 2010).…”

Crop flower visitation by honeybees, bumblebees and solitary bees: Behavioural differences and diversity responses to landscape

“…To define low, moderate and high quality habitats, this categorical descriptor incorporated information on the availability of non-crop foraging habitat, nesting habitat and the intensity of agricultural land use. In the case of the honeybees, high quality habitats could have provided a greater availability of foraging resources in periods preceding peak oilseed rape flowering, which may have led to increased colony provisioning and so colony growth (Avni et al, 2009). Greater numbers of workers per colony would have had a knock on impact on visitation rates.…”