Eusocial bee species are exposed to different toxic element profiles despite foraging within the same landscape

Abstract Bees encounter heavy metals while foraging, which can impair physiology, behaviour and fecundity, with potential consequences for colony health and pollination services. As metal contamination is widespread, exposure varies with environmental context and species‐specific traits; consequently, eusocial bee species may differ in their risk of toxicant exposure. Honey bees are frequently used as proxies for environmental contamination, yet their reliability for representing other bee species remains unclear. This study compared heavy metal bioaccumulation in two eusocial bee species, Bombus terrestris and Apis mellifera , foraging within the same region. B. terrestris colonies were deployed within A. mellifera apiaries in Cambridgeshire, UK, an area characterized by relatively low soil metal contamination. Pollen samples were collected using species‐specific pollen traps, and concentrations of arsenic, cadmium, chromium, lead and tin were quantified in both pollen and adult bee bodies. Despite colonies being located within 50 meters of each other, B. terrestris and A. mellifera ‐collected pollen with significantly different heavy metal concentrations. B. terrestris pollen contained 2–7× higher concentrations of As, Cr, Co, Pb and Sn than A. mellifera , and B. terrestris workers had higher body metal loads than A. mellifera ( β = −1.13, p < 0.001). These findings (1) demonstrate species‐specific differences in metal bioaccumulation, even within the same landscapes, (2) demonstrate that metal exposure remains relevant even in low‐contamination landscapes and (3) indicate that honey bees are not reliable proxies for assessing contaminant burdens in other bee species.