pollen

Why do honey bees waste pollen?

honey-bee-with-pollen

A beekeeper in Nebraska said she found a hundred or so pollen pellets on her screened bottom board. She said she watched for a long time, but the busy bees completely ignored the fallen pellets. She wanted to know why the bees didn’t pick them up. “If honey bees are so careful to conserve nectar and wax, why are they so sloppy about pollen?”

Pellets are hard to move

The problem honey bees have with pollen pellets is simple: they cannot easily pick them up. It seems like they should be able to, after all, honey bees move all kinds of debris out of the hive, such as dead bees, deformed brood, small predators, pieces of cardboard and wood chips. But for some reason, picking up a pollen pellet, moving it to a storage comb, and dropping it in a cell seems to be an impossible task.

Honey bees have very specific ways of dealing with pollen. In the field, the tiny particles stick to their bodies due to electrostatic charges. The bees then groom the pollen from their bodies. Using all six legs, they eventually stuff the pollen into the corbiculae, where it is squeezed into place by the action of the pollen press on their rear legs.

The movement of pollen in the hive

According to The Biology of the Honey Bee (1991) by Mark L Winston, once the pollen forager returns to the hive, she removes the pellets with her middle legs and drops them into in a pollen cell. This is very different from the movement of nectar in the hive, which is passed from bee to bee before it is stored.

Once the pollen load is removed, the forager leaves the area and house bees of a particular age press the pollen into the bottom of the cell with their mandibles and forelegs. During this step, the workers moisten the pellets with “regurgitated honey and saliva.” Additionally, the saliva contains enzymes that help preserve the pollen while it’s in storage. According to Seeley (1982), these pollen handlers are 12–25 days old with a mean age of 16.3 days.

Lost on the bottom board

But if the pollen pellet should become dislodged from a bee’s leg while she is in the hive, it drops to the bottom where the other bees ignore it. If they need more pollen, they go out and get a fresh supply. According to Dr. Norman Gary in The Hive and the Honey Bee (2015), “to collect a full load of pollen a bee may spend as little as 6–10 minutes.” Who knows? Perhaps collecting more pollen takes less time than trying to retrieve the dropped load.

Personally, I have never seen a honey bee attempt to move a pellet with her mandibles. Similarly, pollen fed to honey bees as supplementary feed is usually pulverized into dust or mashed into a moist cake.

Although I have heard of beekeepers feeding pollen pellets by sprinkling them on a piece of paper above the top bars, these would be munched like a pollen patty, not transported to a storage cell. Furthermore, the pellets would be subject to drying into hard little nuggets with the consistency of gravel.

What is your experience? Have you ever seen a honey bee try to collect a dropped pollen pellet? How do you feed pollen pellets back to your bees?

Rusty
Honey Bee Suite

honey-bee-with-pollen

Honey bee with a pollen load. If she loses it, she starts again. Pixabay photo.

22 Comments

  • During my last inspection I turned a frame on its side and a few pellets fell out so I popped them onto the landing board thinking the bees would pick them up and take them back in, but they showed zero interest. I decided the reason must be that they are not programmed to collect pollen that way and therefore do not recognise it as something valuable. As your post says, the reason they get pollen on them is due to electrostatic charge and their natural grooming behaviour allows them to transfer it between their bodies and the hive.

  • I imagine bumbles would do the same. Solitary bees carry their pollen back in a much looser state, only taking time to groom off their loads once at their individual (protected from predators) nests.

    Thanks, Glen

  • In the spring and early summer before the mite population increases, I remove the bottom board with pollen on it and dump it on the hive entrance. The pollen disappears soon after that so I’m assuming the bees take it because it doesn’t end up on the ground in front of the hive.

  • We had a speaker from the Beltsville bee lab at our last meeting and he informed us that colonies will not use pollen that is older than ~10 days. In the midst of their research studies, the scientists noticed that full pollen frames would be left untouched. The bees would consume pollen that had been freshly collected (within 10 days or so) but leave the older pollen alone. Apparently the longer the pollen was in the frames, the more it deteriorated. So the bees would always use the fresher pollen. Interesting, yes?

    • Anna,

      Yes, very interesting. So what do bees do for protein over the winter months if they won’t eat the stored bee bread? What is the point of even storing it? I see lots of stored pollen in fall and I see empty frames in spring, so where did it all go? Please tell us more.

      • I don’t know the answers, I will see if we have his contact information. Maybe they use it despite their preferences? I’ll see what I can find out.

  • I know this is an old post, but had to reply because I have just witnessed something exciting! I also, always wondered why my bees didn’t pick up the dropped pollen pellets. Today, as I was observing them with my binoculars (interesting thing I’ve been doing lately – I sit about 6 feet from the entrance and watch them with binoculars so I can see the details of their little bodies and watch their behaviors) I saw a pollen pellet sitting on the landing board. That didn’t surprise me as I’ve seen plenty of these little pollen pellets before – just sitting on the landing board ignored by the bees. What did surprise was when I witnessed a bee come out of the entrance, sniff around on the landing board until she came to the little pollen pellet, gingerly pick it up in her little mandibles, and take it inside the hive! I was amazed, and don’t think I ever would have seen all that if I hadn’t been watching with binoculars.

    • Denise,

      That is a really interesting observation, and I don’t believe I’ve ever seen that happen. I think I will try your binoculars method.

  • I have a Warre Hive TB hive. I am having a hard time distinguishing if my hive is being robbed or if it is just mass return of foragers at the same time new bees are orienting. I have seen a few bees exit with pollen but not as many as that go in with pollen. I have not seen fighting, only a bee or two being dropped outside during the melee as I would expect in normal cleaning and there are no bees flying all around the hive trying to find other ways in. If I reduce the entrance, they bundle in the tiny opening, and push and bite the reducer material. It happens twice in the afternoon. lasts about 15 min. Mornings are eerily quiet. between 7:00 and noon. Just a few in and out flights. I opened the top this morning and looked in and there were bees along every bar seam. This hive was hit two nights in a row by a bear before I put up an electric fence. I was not sure if the queen was damaged. It will be about 5 weeks since the bear this week. Thanks.

    • Laura,

      It doesn’t sound like robbers. They usually come early and stay late and, as you recognize, they look for other openings. Robbers don’t carry pollen either, so that’s another clue.

    • Ann,

      Several months, at most. Bees don’t store pollen for long-term use, only short-term use. It becomes hard and dry and useless.

      • I was confused by this also. So when they’re feeding winter brood, they’re not actually feeding them pollen, they’re feeding them their own … fat bodies?

      • Wait, what? All those frames from a dead-out hive with stored pollen will be treated as just more trash by the new residents? For that matter, all those frames with last year’s stored pollen in the live hive are also trash come spring?

        • The bees will pull those marbles out when they get loose enough, or you can try turning the frames upside down and shaking them. Often in spring, I’ve seen a layer on the screened bottom that’s over an inch deep.

          • Hmm. So is it worth trying to collect the discarded pollen, grinding it up and making pollen patties out of it? Or is it past its sell-by date?

          • I’m going to have to dig to find the exact numbers (I may have written a post about this, though I can’t remember), but pollen degrades really fast. It can retain its nutritive properties for a few months if it’s kept cool, dry, airtight, and dark. Freezing preserves it a little longer up to a year or two. Bees can keep it for a while in the dark hive by covering it with nectar, which keeps out most of the air. But in any case, the amino acids and proteins break apart, quickly rendering it useless.

          • In “The Hive and the Honey Bee,” Gene Robinson writes, “Fresh pollen, which was 100 percent effective in stimulating the development of hypopharyngeal gland development in worker bees, lost 76 percent of its effectiveness after being stored for one year. Two-year-old pollen did not stimulate gland development or support brood rearing. Brood rearing by bees fed 1- or 2-year-old pollen is often sporadic and spotty, lacking the biological potency of those fed fresh pollen.”

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