The importance of plantain (Plantago spp.) as a supplementary pollen source in the diet of honey bees

Abstract

SummaryPlantain (Plantago spp.) is generally considered to be an anemophilous plant that produces pollen of low nutritional value to bees. Between April and September during 2002 and 2003, in two regions in northwestern Portugal, we studied both the pollen collected by honey bee colonies and airborne pollen. Plantain pollen collection by honey bees was observed only in three different periods, despite its continuous presence in the air. This behaviour was related to the beginning and ending of flowering of the honey bee's main nutritional pollen sources, with no other factor seemingly influencing the temporal collecting patterns. The collection of Plantago spp. pollen was observed in the gaps between the flowering of Eucalyptus spp., chestnut (Castanea sativa), wild blackberry (Rubus spp.) and heaths (Ericaceae family). The results suggest that pollen of Plantago species seems to be used by honey bees as a substitute for other more nutritious pollen types and is collected only as a supplementary source. The temporal patterns of Plantago pollen collection by honey bees could therefore be used as a valuable ecological indicator of periods with low availability of highly nutritious pollen sources.