Prolonging the sweet taste

Most nectar-supping insects land on a flower, take a bit of nectar, then fly off. But bees are different. They hang around the flower, sometimes gorging for ten seconds or more, if there’s enough nectar. Why the difference? Scientists think they have found the glue that keeps a bee stuck to a flower.

Insects (and people, too) are rewarded by their brains for discovering and devouring sugar. There’s a neuron for that – a biological wire that connects tongue and brain and shouts “Joy!”when sweetness hits the palate.

Humans experience satiation when we (for example) start munching a box of chocolates. The first chocolate is great, but by the time we finish all 24 in the box, we’ve had it. Our stomach might be able to hold another package or two, but our tongue and brain are hopefully telling us that we’ve had enough. However, if you were a social bee, you’d want to completely fill your honey tummy because you’re not just eating for yourself – it’s your duty to tank up with as much sweet stuff as you can hold and then pilot your blimp-body back to the hive.  [A honey bee weighs 90 mg (0.0002 lb) but her stomach can hold about 50 mg of nectar – that’s like a 200-pound person eating 110 pounds of chocolates.]

The point is, the bee has to keep loading up on nectar long after the delight is gone. With most other insects, that delight lasts a second or two. But a bee’s neurology has evolved to keep the bee eating. To do this, a neat trick is played on the bee’s taste sensors. First, she notices the sweetness. This attracts her to flowers with a high proportion of sugar (sucrose, fructose, glucose, and maltose) and makes her take that first big gulp. This is in response to a neuron (similar to our own) that says “Sweet”.  But then, a second neuron switches on and overrides the pleasure neuron. The second is an inhibitor neuron which quickly shuts itself off, allowing the first neuron  to take control again, giving the bee the taste of sweetness all over again, as if it were the first time she has tasted that flower’s nectar. The intermittent (burst) firing of the second neuron prevents the bee from experiencing sweetness satiation (adaptation). This research is captured in a paper called “Burst firing in bee gustatory neurons prevents adaptation” recently published in Current Biology. The researchers worked with bumblebees but I suspect that the system is similar in honey bees.

About Ron Miksha

Ron Miksha is a geophysicist who also does a bit of science writing and blogging. Ron has worked as a radio broadcaster, a beekeeper, and is based in Calgary, Alberta, Canada. He has written two books, dozens of magazine and journal articles, and complements his first book, Bad Beekeeping, with a popular blog at www.badbeekeepingblog.com. Ron wrote his most recent book, The Mountain Mystery, for everyone who has looked at a mountain and wondered what miracles of nature set it upon the landscape. For more about Ron, including some cool pictures taken when he was a teenager, please check Ron's site: miksha.com.
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10 Responses to Prolonging the sweet taste

  1. Hi Ron. Thanks for your continued bee and honey writing. I like it. I have a question about the hive set up to use for the best for the bees. I read Tautz’s book and what I recall is that the bees use the honeycomb as a means of communication by vibrating. One bee can “talk” to many others on that comb by vibration. Given that is actually factual, it seems clear to me changing the comb material by using plastic foundation or even complete plastic frames with plastic pre-drawn comb would take away this means of communication from the hive. What do you think about that? Is my logic flawed? Thanks and SWEET greetings to you and your girls in Canada.
    CIAO Stefan

    Liked by 1 person

    • Ron Miksha says:

      Hello Stefan,
      That’s a great question. I’ve never considered this before. Though I don’t know of any studies specifically about bees’ communication on wax foundation vs plastic-base frames, I suspect that it is not a problem. If it were an issue, we would have seen something on a forum somewhere by now because beekeepers would notice and complain about a difference in production between plastic- and wax-based based hive production.
      It’s an interesting thought, but plastic frames of various sorts have been around for fifty years (though much more common now). Nevertheless, I’ve not heard of a communication/vibration problem.
      Ron

      Like

  2. joel says:

    I truly enjoy reading your blog , and actually very much look forward to these letters in my mail box . It is very interesting to learn the relation of neuron and consumption of nectar , in short it is very much an addiction , from which all civilization have benefited , looking at it on a different aspect , could this also point out to a different treatment for human such as alcohol , drug and very much food abuse which for many are an addiction leading to various consequences , when some say they are wired differently , You post could not illustrate it more conclusively .
    researcher need only to isolate which neuron and which chemical make them react ,
    Who said you could not learn from an insect .

    Liked by 1 person

    • Ron Miksha says:

      I think you are right. I thought of something like this (regarding our tendency to over-eat) when I wrote this piece. Your idea about addiction treatments is probably right but maybe a decade or two into the future.

      Like

  3. Thanks for taking the time to highlight this journal article. It is always good to hear about new research related to bees.

    Like

  4. Ron Miksha says:

    This question arrived by email to me:
    Great opportunity to finally get rid of a question I had for some time.
    Bees fill the honey tummy to carry the nectar back to their home to share with family.
    I understand that wasps, yellow jacket and bald faced, can rob a hive clean down to their underwear in no time. How do they do that?
    Do they “eat” all the honey on the spot? Do they have containers to haul honey back to their home?

    Here is the best answer I could come up with on short notice:
    I am not a wasp expert, but as you know, wasps attack honey bee colonies by arriving in large numbers and try to rob both honey and larvae. Their first tactic is to engage the guard bees and outnumber them so that other wasps can enter the hive. Since wasps are social insects and raise their young in nests, I assume that they carry back food (from bee larvae and honey) in their stomachs. I think they overwhelm and destroy bee colonies by shear numbers of invaders. The defence is use of reduced bee hive entrances, maintenance of strong hives, and wasp traps.

    A good general public wasp info site is from the City of New York website:
    https://www1.nyc.gov/site/doh/health/health-topics/wasps.page
    Which talks about wasp nutrition:

    Wasps satisfy their nutritional need for protein by preying on other insects. They feed on a variety of garden pests. The diet of a paper wasp, for instance, includes corn earworms, armyworms, tobacco hornworms, etc., while yellowjackets and bald-faced hornets feed on house flies, blow flies, and harmful caterpillars. Wasps also require sugar and will feed on plant nectar and fruit to satisfy this need. Yellowjackets often scavenge for sugary foods at picnic sites and near garbage disposals. Many summertime picnic-goers endure the pest-like behavior of yellowjackets attempting to carry off pieces of their meal.

    Like

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