Species-specific elemental profiles in three Hymenoptera species under shared environmental exposure: implications for biomonitoring

Abstract

This study compared the elemental composition of worker honey bees (Apis mellifera), German wasps (Vespula germanica), and European hornets (Vespa crabro) collected from a single rural apiary to evaluate interspecific differences under shared environmental exposure and assess the implications of these differences for biomonitoring of trace element pollution. Thirty elements, including essential and potentially toxic trace elements, were quantified by ICP-MS. Significant differences were observed for most elements. Hornets showed the highest concentrations of many trace and potentially toxic elements (e.g., Al, V, Fe, Ni, Ba, Pb), whereas wasps consistently exhibited the lowest levels. Honey bees showed intermediate concentrations for most elements but had significantly higher levels of Mg, P, K, Ca, Cr, Zn, and Mo than at least one of the other species. Multivariate analyses supported these patterns. Principal component analysis showed that PC1 (66.8%) separated hornets from bees and wasps along a gradient of trace and potentially toxic elements, while PC2 (22.4%) distinguished honey bees from wasps based on macroelements. Hierarchical cluster analysis confirmed this separation, with hornets forming a distinct cluster and bees and wasps forming separate subclusters. These differences reflect species-specific exposure pathways, foraging range, and physiological regulation of element uptake rather than environmental heterogeneity. The results demonstrate that closely related hymenopteran species provide distinct biomonitoring signals even under shared environmental exposure, highlighting the importance of species selection and taxon-specific interpretation in insect biomonitoring.