Exposure to pesticides during development negatively affects honey bee (Apis mellifera) drone sperm viability

PLoS One. 2018 Dec 13;13(12):e0208630. doi: 10.1371/journal.pone.0208630. eCollection 2018.

Abstract

Honey bee (Apis mellifera) colonies invest a substantial amount of colony resources in the production of drones during the reproductive season to enable mating with virgin queens from nearby colonies. Recent studies have shown significant differences in the production of sperm cells that are viable (i.e., sperm viability) and can fertilize an ovule among sexually mature drones that are exposed to different environmental conditions during development or as adults. In particular, sperm viability may be negatively affected during drone development from exposure to pesticides in contaminated beeswax. To assess whether sperm viability is negatively affected during drone development from exposure to beeswax contaminated with in-hive pesticides, we compared the viability of sperm collected from drones reared in pesticide-free beeswax with that of drones reared in beeswax contaminated with field-relevant concentrations of the pesticides most commonly found in wax from commercial beekeeping operations in the United States. These pesticides include the miticides fluvalinate, coumaphos and amitraz, and the agro-chemicals chlorothalonil and chlorpyrifos. Sperm from drones collected at 10 and 18 days post emergence were classified as viable or non-viable to calculate sperm viability. For all pesticide treatment groups, drones that were reared in pesticide-laden beeswax had lower sperm viability compared to those reared in pesticide-free beeswax. This difference was especially pronounced among drones reared in miticide-laden wax. Our results reinforce the notion that pesticide contamination of beeswax negatively affects the reproductive quality of drones, which can affect the queens they mate with, ultimately compromising colony health.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Bees / drug effects
  • Bees / growth & development*
  • Chlorpyrifos / toxicity
  • Coumaphos / toxicity
  • Environmental Exposure
  • Male
  • Nitriles / toxicity
  • Pesticides / toxicity*
  • Pyrethrins / toxicity
  • Reproduction / drug effects
  • Spermatozoa / drug effects*

Substances

  • Nitriles
  • Pesticides
  • Pyrethrins
  • fluvalinate
  • Chlorpyrifos
  • Coumaphos

Grants and funding

This study was supported in part by funding to JR by a United States Department of Agriculture-National Institutes for Food and Agriculture (https://nifa.usda.gov/) award (2015-67013-23170) and Texas A&M University’s Hatch Project (TEX09557), and by funding to AF from the American Association of Professional Apiculturists. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.