Here we demonstrate for the frst time that field-realistic concentrations of the commonly used neonicotinoid insecticide thiacloprid can severely affect the immunocompetence of Osmia bicornis. In detail, males exposed to thiacloprid solutions of 200 and 555µg/kg showed a reduction in hemocyte density. Moreover, functional aspects of the immune defence – the antimicrobial activity of the hemolymph – were impaired in males. In females, however, only a concentration of 555µg/kg elicited similar immunosuppressive efects. Our results demonstrate that neonicotinoid insecticides can negatively affect the immunocompetence of O. bicornis, possibly leading to an impaired disease resistance capacity.
Immunosuppression response to thiacloprid in the red mason bee Osmia bicornis
