The sugar water/corn syrup/fruitcose vs. honey debate for feeding your bees is a long-standing one.
Recently, I found a Scientific American podcast interview from 2009 in which May Berenbaum, University of Illinois entomologist and bee researcher, discussed that very question with Steve Mirsky of Scientific American.
Here are some of the main points Berenbaum made:
- Honeybee grubs (baby bees) eat a mixture of pollen and honey we call “bee bread.”
- Sugar doesn’t provide bees with some of the enzymes that help bees process plant chemicals.
- Brenebaum: “. . . feeding on nectar or honey derived from nectars [is a] very different proposition from feeding on other types of plant tissue because plants load up their vulnerable tissues with chemicals, you know, natural pesticides, so that insects won’t eat them, but they want insects to eat nectar; that’s the whole point [of nectar].”
- When you substitute a natural food for an artificial one, there may unintended consequences.
Berenbaum has been awarded one of the 10 National Science Medals by President Barack Obama.
The beekeeper in this corner is a big advocate of honey over sugar water in this debate. It’s a lot easier to leave honey in the hive than to take it off and then have to feed them sugar water to get them through the next season. Sometimes that’s not possible, of course, and you do what you can to keep your bees alive. But beekeeper should think ahead and keep as much honey on the hive as possible.
They should also try to provide their bees with plants to feed on during as much of the year (Year-around (almost) blooms for the bees) as possible.
Below is the transcript to this part of the interview, and you can hear the entire interview at this link.
Steve: Welcome to Science Talk, the weekly podcast of Scientific American posted on August 21st, 2009. I’m Steve Mirsky. This week more about bees and all manner of other insect with entomologist, May Berenbaum from the University of Illinois at Urbana–Champaign. Now, last week I promised you that you’d also get a fellow named John Williams, the beekeeper at Darwin’s home in England; however I’m traveling, and I apparently neglected to bring along that audio file, but this problem is easily fixed because what was supposed to be a two-part podcast is now a three-part podcast. I plan to post the William’s chat on Tuesday the 25th of August, so look or listen for that. Meanwhile here’s more with May Berenbaum. Early in our conversation, she mentions Reed Johnson—you’ll recall from part 1 that Reed is her student working on genomes.
Berenbaum: Honeybees, everybody thinks eats honey and pollen, but in reality they feed their grub something called bee bread, which is a mixture of honey and pollen packed into cells, and it cures or ages. And the suspicion is that maybe some of these symbiotic microbes are contributing to the sort of processing of bee bread. So one of the findings from this yet unpublished work that was discussed in Florida at the meeting that Reed attended, Apiary Inspectors of America, was a high-fructose corn syrup which is the preferred diet for overwintering bees because it’s much cheaper than feeding them honey or sugar; apparently it wipes out these potentially symbiotic microbes. One thing that Reed found that’s in his dissertation, when you feed honeybees honey, they upregulate their cytochrome p450 monooxygenases, these enzymes that process among other things plant chemicals, when you give them sugar, it’s nothing. So when you feed them on a sugar diet they are not turning on their chemical processing equipment, so this is something that nobody expected. I mean people aren’t used to thinking of honeybees as broad generalists because they’ll feed on hundreds of different flowers, but in a way they are dietary super specialists because they feed on this narrow range—they feed on pollen, honey and bee bread. And granted the components can come from all different places, but feeding on nectar or honey derived from nectars [is a] very different proposition from feeding on other types of plant tissue because plants load up their vulnerable tissues with chemicals, you know, natural pesticides, so that insects won’t eat them, but they want insects to eat nectar; that’s the whole point [of nectar].
Steve: So it’s possible that this high-fructose corn syrup that’s, you know, partially responsible for the obesity epidemic in humans is also having a devastating effect on the bee population.
Berenbaum: Well, that’s a big jump, but I would say that feeding bees other than honey may have physiological consequences that nobody anticipated. Back in the ’70s the dietary studies were conducted, at least one of the USDA bee labs, and certainly short term there is no longevity effect. And that actually led to the widespread adoption of these alternative diets. But nobody was looking at the microbial symbionts in the gut, nobody was looking at the detoxification enzymes, we didn’t even know to look. So there may be subtle effects. That’s another focus too. As people have for a long time; you know, the way the EPA registers insecticides being safe or unsafe for bees, they do bioassays with adult workers, well adult worker physiology is very different from every other life stage. It’s just really hard to figure out bees. I have worked with caterpillars since, like, 1976. Bees are hard to work with, they are very complicated, they are, I mean they have this amazing social behavior and awareness. Caterpillars are nothing but eating machines, you know. I have seen black swallowtail caterpillars chewing on parsley foliage while the spined soldier bug is sucking out the haemolymph from the other end. They are so intent, all they do is eat, that’s what their, you know, they can increase in size and weight, you know, four to 10,000 fold in a couple of weeks; they eat their weight, their own weight in plant food, that’s what they do. So they have no kind of sense of awareness or recognition of family relationships, so that was one of the really difficult things about doing microarray to determine causes of colony collapse disorder. It’s really a correlative approach, and what complicates things is that you’re looking at genes that are turned on or turned off or turned way up or turned up a little, and there will be genes that are turned on in response to whatever the causative phenomenon might be; but there are also genes whose expression [is being] changed because the social structure [is being] changed. It’s as if you woke up one morning and half of Chicago was gone. Your stress genes would be turned on; that would have nothing to do with whatever wiped out half of Chicago, and that’s what we’re working with microarray. We have the advantage of the human genome; [we] know [a lot] more about what the genes do. So you saw that in the microarray, that big hunk of genes [that] we don’t know what their function is.
Key question for beehive location: Any good restaurants around here?
Year-around (almost) blooms for the bees
Key words: May Berenbaum, National Medal of Science, sugar water vs. honey for bees, Scientific American, Steve Kirsky, bee bread, enzymes that help bees process plant chemicals, University of Illinois, fruitcose, corn syrup