Thiacloprid-Nosema ceranae interactions in honey bees: Host survivorship but not parasite reproduction is dependent on pesticide dose

Interactions between stressors contribute to the recently reported increase in losses of honey bee colonies. Here we demonstrated that a synergistic effect on mortality by the low toxic, commonly used neonicotinoid thiacloprid and the nearly ubiquitous gut parasite Nosema ceranae is dependent on the pesticide dose. Furthermore, thiacloprid had a negative influence on N. ceranae reproduction. Our results highlight that interactions among honey bee health stressors can be dynamic and should be studied across a broader range of combinations. (C) 2014 Elsevier Inc. All rights reserved.