Assessing honey bee (Apis mellifera) health in conventional and organically-kept apiaries for the development of sustainable beekeeping practices

The honey bee (Apis mellifera) is of critical importance to the agricultural systems in the United States. Unfortunately, honey bee populations have been declining for many years. The newest disease, “Colony Collapse Disorder”, has raised concerns for US agriculture. Possible explanations for the decline in honey bee populations include, among others, pests and pathogens, exposure to pesticides, malnutrition, and beekeeping practices. In this study, we investigated honey bee health in two different beekeeping management practices (conventional and organically-kept apiaries). Results indicated that levels of Varroa mite infestations in honey bee colonies from north and south Florida were not significantly different between conventional and organically-kept hives during the 84-day experimental period. There were no or low load of pesticide residues detected in bee samples collected from organically-kept hives; whereas, high levels of several pesticide residues were found in bee samples from conventionally-kept hives. Data also indicated that honey bees from conventionally-kept colonies with 0% Varroa mite infestations had an upregulation of prophenoloxidase (PPO) gene expression levels. Vitellogenin (Vg) gene expression levels were significantly higher in bees from hives with 0% mite infestations and 5-10% mite infestations from organically-kept apiaries when compared to conventionally-kept apiaries. Honey bees from conventionally managed hives with 0% mite infestations significantly down-regulated malvolio (mvl) gene expression compared to organically-kept hives. Data indicated that the expression levels of the gene spaetzle were significantly increased in organically-kept honey bees with 5-10% mite infestations compared to conventional ones. The levels of CYP9Q3 in organically-kept honey bees from hives with 0% mite infestations were significantly upregulated when compared to conventionally managed honey bees; suggesting that diet may influence the honey bee’s ability to detoxify pesticides.