Formation of Hydroxymethylfurfural in Domestic High-Fructose Corn Syrup and Its Toxicity to the Honey Bee (Apis mellifera)

In the United States, high-fructose corn syrup (HFCS) has become a sucrose replacement for honey bees and has widespread use as a sweetener in many processed foods and beverages for human consumption. It is utilized by commercial beekeepers as a food for honey bees for several reasons: to promote brood production, after bees have been moved for commercial pollination, and when field-gathered nectar sources are scarce. Hydroxymethylfurfural (HMF) is a heat-formed contaminant and is the most noted toxin to honey bees. Currently, there are no rapid field tests that would alert beekeepers of dangerous levels of HMF in HFCS or honey. In this study, the initial levels and the rates of formation of HMF at four temperatures were evaluated in U.S.-available HFCS samples. Different HFCS brands were analyzed and compared for acidity and metal ions by inductively coupled plasma mass spectroscopy. Levels of HMF in eight HFCS products were evaluated over 35 days, and the data were fit to polynomial and exponential equations, with excellent correlations. The data can be used by beekeepers to predict HMF formation on storage. Caged bee studies were conducted to evaluate the HMF dose-response effect on bee mortality. Finally, commercial bases such as lime, potash, and caustic soda were added to neutralize hydronium ion in HMF samples, and the rates of HMF formation were compared at 45 degrees C.

Beta-cyclodextrins as carriers of monoterpenes into the hemolymph of the honey bee (Apis mellifera) for integrated pest management

The Varroa mite ( Varroa destructor) is becoming ubiquitous worldwide and is a serious threat to honey bees. The cultivation of certain food crops are at risk. The most noted acaricides against Varroa mites are tau-fluvaninate and coumaphos, but the mites are showing resistance. Since these insecticides are used in the proximity of honey, it is desirable to use natural alternatives. Monoterpenoids such as thymol and carvacrol, that are constituents of oil of thyme and oil of origanum, show promise as acaricides against the Varroa mite ( Varroa destructor), but the delivery of these compounds remains a challenge due to the low water solubility and uncontrolled release into the colony. Beta-cyclodextrin (beta-CD) inclusion complexes of thymol, oil of origanum, and carvacrol were prepared on a preparative scale. Competitive binding was studied by fluorescence spectroscopy by using 6- p-toluidinylnaphthalene-2-sulfonate as a fluorescent probe. The complexes were characterized, and the competitive binding described by (1)H and (13)C NMR spectroscopy chemical shifts. The toxicity of beta-CD and the prepared complexes in enriched sucrose syrup was studied by conducting caged honey bee ( Apis mellifera) feeding trials. After the first and second weeks of feeding, hemolymph and gut tissue samples were acquired from the caged bee study. The levels of thymol and carvacrol were quantified by solid-phase microextraction gas chromatography mass spectroscopy, using an optimized procedure we developed. High (mM) levels of thymol and carvacrol were detected in bee tissues without any imposed toxicity to the bees, in an effort to deter Varroa mites from feeding on honey bee hemolymph.