Bumblebee death associated with Tilia x europaea L

摘要: Abstract For more than six decades, bumblebee death, which mainly occurs in August, has been assumed to be associated with intake of presumed toxic nectar from linden trees (Tilia spp.), a hypothesis sustained by observations significant number dead bumblebees under these during their flowering season. Several theories exist current literature account for observations. The contain compound(s) the including monosaccharide mannose, cannot metabolized bumblebees. presence compounds such as alkaloid nicotine or pesticides anthropogenic origin also indicated. However, none above suggested have hitherto properly characterized nectar. In paper we report on characterization composition trees, were observed. structure determinations performed selective 1D TOCSY NMR and extensive applications 2D spectroscopy. flowers was readily available amounts entire period when observed trees. only contained non-toxic sugars α-glucopyranose, β-glucopyranose, sucrose, fructose minor xylose. did not nor alkaloids pesticides. Initial toxicity studies using brine shrimp lethality assay showed that exhibit any effects even at concentrations higher 1 mg/ml dry weight, providing disproving evidence against assumption nectar's character.