Selective Behaviour of Honeybees in Acquiring European Propolis Plant Precursors

Abstract

Honey bees harvest resins from various plant species and use them in the hive as propolis. While there have been a number of studies concerning the chemical composition of this antimicrobial product, little is known about selective behavior and bee preference when different potential plant sources of resin are available. The main objective of this paper was to investigate some aspects of behavioral patterns of honeybees in the context of resin acquisition. Samples of propolis originating from temperate zones of Europe and the supposed botanical precursors of the product were analyzed. Taxonomical markers of bud resins of two white birch species, aspen, black poplar, horse-chestnut, black alder, and Scots pine were determined through GC-MS analysis. All these trees have been reported as sources of propolis, but comparisons of the chemical composition of their bud resins with the compositions of propolis samples from seven European countries have demonstrated the presence of taxonomical markers only from black poplar, aspen, and one species of birch. This suggests selective behavior during the collection of bud resins by honeybees. To examine the causes of such selectivity, the antimicrobial properties of bud resins were determined. Horse-chestnut resins had lower antimicrobial activity than the other resins which did not differ significantly.Electronic supplementary materialThe online version of this article (doi:10.1007/s10886-016-0708-9) contains supplementary material, which is available to authorized users.

In vitro study of the antimicrobial activity of European propolis against Paenibacillus larvae

“…The peak areas of the extract components obtained by replicate analyses were used for the calculation of their relative standard deviation (RSD) values. On average, RSD amounted to 2% for the main peaks (more than 10% of TIC), 6% for medium peaks (more than 1% of TIC), and 18% for peaks that amounted to ≤0.5% of TIC (Isidorov et al 2016).…”

“…In the mid-latitudes of the northern hemisphere, the plant precursor of propolis is the bud resins (exudates) of some arboreous trees, in particular, different species of poplar, aspen, and birch (Bankova et al 2000;Wilson et al 2013Wilson et al , 2015Isidorov et al 2014aIsidorov et al , 2016. The antimicrobial activity of this natural antibiotic has been attributed to phenolic substances: flavonoid aglycones, and phenolic and hydroxycinnamic acids (Kujumgiev et al 1999).…”

“…In a more recent investigation, taxonomical markers of the resins from the buds of these trees were determined (Isidorov et al 2016). Black poplar bud resin is characterized by a high content of phenols such as pentenyl (mostly, prenyl) cinnamates, chalcones, and the unsubstituted B ring flavonoids: pinocembrin, pinostrobin, chrysin, galangin, pinobanksin, and their 3-substituted derivatives (Isidorov and Vinogorova 2003).…”

“…Black poplar bud resin is characterized by a high content of phenols such as pentenyl (mostly, prenyl) cinnamates, chalcones, and the unsubstituted B ring flavonoids: pinocembrin, pinostrobin, chrysin, galangin, pinobanksin, and their 3-substituted derivatives (Isidorov and Vinogorova 2003). Downy birch and common aspen bud resins are disting u i s h e d b y t h e p r e s e n c e o f s p e c i f i c phenylpropenoids, hydroxycinnamic acid esters of sesquiterpene alcohols, and glycerol, respectively (Isidorov et al 2014a(Isidorov et al , 2016. Although bees from the same colony often collect resins from more than one of these tree species, three main Btypes^of European propolis can be distinguished on the basis of the species-specific chemical composition: poplar-, birch-, and aspen-type (Popova et al 2012;Isidorov et al 2014aIsidorov et al , 2016.…”

“…Downy birch and common aspen bud resins are disting u i s h e d b y t h e p r e s e n c e o f s p e c i f i c phenylpropenoids, hydroxycinnamic acid esters of sesquiterpene alcohols, and glycerol, respectively (Isidorov et al 2014a(Isidorov et al , 2016. Although bees from the same colony often collect resins from more than one of these tree species, three main Btypes^of European propolis can be distinguished on the basis of the species-specific chemical composition: poplar-, birch-, and aspen-type (Popova et al 2012;Isidorov et al 2014aIsidorov et al , 2016. Probably, the differences in the chemical composition are reflected in the antimicrobial activity of different Btypes^of propolis; however, little is known about the effects of different types of European propolis on P. larvae .…”