PLoS ONE (Jan 2019)

Influence of chronic exposure to thiamethoxam and chronic bee paralysis virus on winter honey bees.

  • Marianne Coulon,
  • Frank Schurr,
  • Anne-Claire Martel,
  • Nicolas Cougoule,
  • Adrien Bégaud,
  • Patrick Mangoni,
  • Gennaro Di Prisco,
  • Anne Dalmon,
  • Cédric Alaux,
  • Magali Ribière-Chabert,
  • Yves Le Conte,
  • Richard Thiéry,
  • Eric Dubois

DOI
https://doi.org/10.1371/journal.pone.0220703
Journal volume & issue
Vol. 14, no. 8
p. e0220703

Abstract

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Co-exposure to pesticides and viruses is likely to occur in honey bee colonies. Pesticides can be present in pollen, nectar, and persist in stored food (honey and bee bread), and viruses can be highly prevalent in honey bee colonies. Therefore, the present study describes the influence of chronic co-exposure to thiamethoxam and Chronic bee paralysis virus (CBPV) on bee survival, virus loads, expression level of immune and detoxication genes, and pesticide metabolism Experiments were performed on honey bees collected from a winter apiary with reduced viral contaminations. No synergistic effect of co-exposure was observed on bee survival, nor on the ability of bees to metabolise the pesticide into clothianidin. However, we found that co-exposure caused an increase in CBPV loads that reached the viral levels usually found in overt infections. The effect of co-exposure on CBPV replication was associated with down-regulation of vitellogenin and dorsal-1a gene transcription. Nevertheless, the observed effects might be different to those occurring in spring or summer bees, which are more likelyco-exposed to thiamethoxam and CBPV and exhibit a different physiology.