Effect of hydroxymethylfurfural (HMF) on mortality of artificially reared honey bee larvae (Apis mellifera carnica)

Abstract

Hydroxymethylfurfural (HMF) is a heat-formed, acid-catalyzed contaminant of sugar syrups, which find their way into honey bee feeding. As HMF was noted to be toxic to adult honey bees, we investigated the toxicity of HMF towards larvae. Therefore we exposed artificially reared larvae to a chronic HMF intoxication over 6 days using 6 different concentrations (5, 50, 750, 5000, 7500 and 10,000 ppm) and a control. The mortality was assessed from day 2 to day 7 (d7) and on day 22 (d22). Concentrations ranging from 5 to 750 ppm HMF did not show any influence on larval or pupal mortality compared to controls (p > 0.05; Kaplan-Meier analysis). Concentrations of 7500 ppm or higher caused a larval mortality of 100%. An experimental LC50 of 4280 ppm (d7) and 2424 ppm (d22) was determined. The calculated LD50 was 778 µg HMF per larva on d7 and 441 µg HMF on d22. Additionally, we exposed adult honey bees to high concentrations of HMF to compare the mortality to the results from larvae. On d7 larvae are much more sensitive against HMF than adult honey bees after 6 days of feeding. However, on d22 after emergence adults show a lower LC50, which indicates a higher sensitivity than larvae. As toxicity of HMF against honey bees is a function of time and concentration, our results indicate that HMF in supplemental food will probably not cause great brood losses. Yet sublethal effects might decrease fitness of the colony.

Hydroxymethylfurfural Affects Caged Honey Bees (Apis mellifera carnica)

“…Except for these small-scale studies, few studies have systematically examined the effect of HMF on bee health and physiology, which is surprising given that concentrations of 7500 ppm HMF (mg/kg) or higher have been reported to cause massive bee kills, i.e., 100% mortality of bee larvae with LC 50 for larvae ranging from 2424 ppm to 4280 ppm. Thus, larvae appear far more sensitive to HMF than adult honey bees [26]. Clearly, our results coupled with evidence cited earlier confirm the toxicity of HMF to adult and developing honey bees and the need for its mitigation in commercial bee yards.…”

5-Hydroxymethylfurfural (HMF) levels in honey and other food products: effects on bees and human health

“…In another study, a sugar solution containing 30–150 mg/kg of HMF was used to feed honey bees and was found to cause 15–58.7% of deaths of caged bees within 20 days [ 78 ]. Krainer et al [ 88 ] reported that the LD50 values of HMF for bee larvae fed for more than 6 days were 4280 and 2424 mg/kg on days 7 and 22, respectively. Interestingly, they found that 7-day larvae emerging after being fed HMF for 6 days were more sensitive than were adult bees, but the emerging adult bees at day 22 were less sensitive.…”

Suitability of Starch Syrups for Winter Feeding of Honeybee Colonies

“…One of the basic disadvantages of the readyto-use foods used in feeding bees, irrespective of the food type (inverted sucrose, starch) is the content of 5-hydroxymethylfurfural, also called HMF, which is harmful for bees (Jachimowicz & El Sherbiny, 1975;LeBlanc et al, 2009). This compound is created in the production process of these foods, and the amount of this compound depends on the temperature and acidity of the environment (Krainer et al, 2016). A high concentration of HMF in products used to feed bees can upset the proper functioning of bee colonies (Van der Zee & Pisa, 2010).…”

“…The amount of food provided to bees, is a one-time dose and the time of supplying winter supplementation is an important element of the so-called winter feeding of bee colonies (Pidek, 1985;Severson & Erickson, 1984;Seeley & Visscher, 1985;Pedersen, Pedersen, & Pedersen, 1996;Skubida, 1998). To supply winter food, beekeepers can use sugar syrup, sucrose inverted syrup, starch syrup or high-fructose corn syrup (HFCS) (Jachimowicz & El Sherbiny, 1975;Skubida, 1998, von der Ohe & Schönberger, 2002Liebig, 2005;Ceksteryte & Racys, 2006;LeBlanc et al, 2009;Brodschneider & Crailsheim, 2010, Sammataro & Weiss, 2013Krainer at al., 2016). Sugar syrup (a mixture of water and pure sucrose from sugar beets or sugarcane) has been used for many years to feed honeybees (Free & Spencer-Booth, 1961;Barker, 1971;Bobrzecki, 1976;Gromisz, 1985).…”