feeding bees

Hydroxymethylfurfural is not good for bees

Hydroxymethylfurfural is the main reason that high-fructose corn syrup is not good for bees. Also known as HMF, hydroxymethylfurfural is a chemical that forms when high-fructose corn syrup is heated. It is known to damage honey bees by causing ulceration of the gut.

Lately it has become one of the suspects in the deaths of millions of honey bees across the globe. Beekeepers often supplement a colony’s diet with high-fructose corn syrup, especially in the early spring when they want colonies to build up quickly for the pollination season.

Heat makes it worse

Researchers have found that the more high-fructose corn syrup is heated, the more HMF is formed, and the production takes a big jump at around 120°F. Now 120°F isn’t very hot. It’s a bit warmer than the hot water in your tap, or sort of like a summer day in Death Valley. HMF formation also increases over time, so old high-fructose corn syrup contains more than new syrup.

The temperature inside a hive can easily be warm enough to produce HMF, so it is very possible that it has an effect on honey bee health. High-fructose corn syrup is most often used by commercial beekeepers. Tariffs on sugar imports keep sugar prices high, whereas domestic corn is subsidized, so high-fructose corn syrup becomes a cheap and easy-to-use alternative to sugar. Many commercial beekeepers buy it in tanker loads and fill their hive-top feeders with hoses that pump the stuff in. The bees are not hesitant to eat it and a colony will consume gallons.

Is is really a problem?

High-fructose corn syrup continues to be popular with commercial beekeepers, many of whom say they’ve been using it for years and it hasn’t hurt their bees. On the other hand, we know that bee hives have become hard to maintain, colony numbers are dropping, and something is causing bee declines. If scientific experimentation shows that high-fructose corn syrup is part of the problem, we probably should be listening.

If you are debating about what to feed your bees, and you don’t have honey from your own apiary, use sugar syrup. Some types of high-fructose corn syrup have less HMF than others, but until all the evidence is in, plain old sugar made into syrup is probably the safest bet. I will update this site as more information about HMF becomes available.

Honey Bee Suite

LeBlanc et al. Formation of Hydroxymethylfurfural in Domestic High-Fructose Corn Syrup and Its Toxicity to the Honey Bee (Apis mellifera). Journal of Agricultural and Food Chemistry, 2009; 57 (16): 7369 DOI: 10.1021/jf9014526

There is still much we don't know about honey bee health.

There is still much we don’t know about honey bee health. Image by Jaesung An from Pixabay


  • A blend of invert sugar or all invert sugar is better than cane sugar if you need to feed your bees. Cane sugar-fed bees are more likely to develop high varroa counts in 2-3 months than when fed invert sugar. HFCS: not even the industrial beekeeper use that any more…I hope!

    • Tina,

      “Cane sugar-fed bees are more likely to develop high varroa counts in 2-3 months than when fed invert sugar.” Sounds interesting. Please share your source of information with us!

    • Bonnie,

      Bees get into all kinds of things with few ill effects, and I’m sure a few candy canes won’t hurt your bees. In fact, candy canes have been fed to bees before as discussed in this post. But, seriously, why would you want to feed your bees food coloring and other additives? If your bees need to be fed, feed them plain sugar or sugar syrup without colors, preservatives, emulsifiers, or starches. Bees are after all living things, not garbage disposers.

  • “Cane sugar-fed bees are more likely to develop high varroa counts in 2-3 months than when fed invert sugar.”
    Damn if you do, damn if you don’t.
    Did anything come out of this?
    I have gone to great length to find cane sugar because all of our beet sugar is GMO which I wanted to avoid.
    Which is the lesser evil?

  • Heating any sugar, not just HFCS, produces hydroxymethylfurfural. I’ve done some reading, and it is a VERY complicated issue. My limited view of the subject: short-term heating to make sugar syrup is not a problem. Feeding small amounts of products heated longer (DIY Pro-Sweet, etc) also likely not a problem but more frequent use may be. For a deep dive in an academic article: https://www.google.com/url?sa=t&source=web&cd=2&ved=2ahUKEwiTitjQgIPlAhVgFjQIHeoXDokQFjABegQIBxAB&url=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC5884753%2F&usg=AOvVaw1mN7wwO6gTkFUhrG5ngz7t

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