A shortage of pollen for bees
A shortage of pollen is a relatively new concern for beekeepers. Once upon a time, pollen was taken for granted. But today, a bountiful and diverse supply of pollen is sometimes lacking. Habitat loss, invasive plants, monoculture farming, and herbicides are just some of the reasons.
A pollen grain is simply a small package containing the male genetic material of a plant, so a frame of bee-collected pollen is like a gigantic sperm bank, except the sperm is lost to the plants forever. Instead, it becomes food for bee larvae . . . kind of an odd menu item, when you think about it.
Help wanted: move pollen
Since plants can’t walk, jump, swim, fly, or bar-hop, they need a way of moving their pollen around. The most significant mover of pollen is the wind. The grasses—the family of plants that includes wheat, rice, maize, millet, sorghum, barley, oats, and rye—are wind pollinated, as well as most conifers and ferns.
But plants with showy flowers are often pollinated by animals. At least they once were, before mankind began tinkering with them. Today, some of the showiest blooms have little or no usable pollen—another reason for the shortage of bee food.
Many bees, including honey bees, collect multiple kinds of pollen and can adapt when a particular type becomes scarce. However, many native bees are completely dependent on a single plant species and cannot survive without it.
In addition, native bees feed their larvae in a different way. In most bee species, pollen is collected, moistened with nectar, and formed into a ball inside the nest. The female bee lays an egg atop the ball so that when the egg hatches, the larva can eat the sweetened pollen—the equivalent of bee bread—and the royal jelly step is skipped altogether.
How to nurse a larva
Not all pollen is created equal, not even close. Just as human food varies in nutritional content, so does pollen. Some are higher in protein or amino acids, some have more lipids, some have a greater variety of vitamins or micronutrients. Go to a farmer’s market at the height of the season and admire the produce—all the colors, textures, shapes, and sizes. Just as you can identify a plant based on its fruit, you can also identify a plant based on a single grain of pollen. Each is unique.
As beekeepers, we know that pollen is necessary for brood rearing. But the youngest honey bee larvae do not eat pollen directly. Instead, the nurse bees eat the pollen in the form of bee bread. Such a protein-rich diet stimulates their hypopharyngeal glands to secrete royal jelly, which is then fed to the young larvae. After about three days, the worker and drone larvae are switched to a diet of pollen and diluted honey.
As older adults, honey bee foragers eat energy-rich honey almost exclusively. Because foragers don’t eat bee bread or pollen directly, when they need protein, they beg the nurse bees for it. That’s right, nurse bees feed both larvae and foragers.
Don’t ask me, I just work here
So the foragers that collect pollen don’t eat it, they just pack it home. Sometimes foragers will bring home other stuff—sawdust or coffee grounds, for example—that have a powdery consistency and the right particle size. This has led some researchers to believe that honey bees cannot determine the food value of pollen.
However, other research has shown that although foragers may collect inferior pollen or non-pollen, the nurses—the ones that actually have to eat the stuff—are much more selective. Think of mom coming home from the market with parsnips and rutabagas. The kids sneer: “Really? Where’s the food?” In the hive, the nurses may discard some of the treasures their sisters brought home from the field, including pollen with questionable food value and sometimes that pricey pollen substitute.
The need varies with brood rearing
When you understand how pollen is used in the hive, you can see why a colony doesn’t need a large supply during winter. In late autumn through mid-winter, when there is little brood production, a colony can get by with very little. However, heaps of good quality pollen are needed throughout the major brood-rearing periods, especially in late winter and early spring.
In highly built-up areas, or in places with lots of agriculture and herbicide use, pollen may be especially scarce in early spring and again in late summer or early autumn. Pollen substitute is often used at these times.
It’s a shame we spray roadside weeds with herbicides and then feed our bees soybean meal. In fact, we humans do so much stupid stuff, you have to wonder how we survive. I know, I know. You say that if we don’t spray for invasive weeds, they will overrun the landscape. I say, if we hadn’t sprayed the native weeds in the first place, the invasives wouldn’t have had an opportunity to start. Oh well, too late now.
Natural pollen is the best
If you are not a commercial beekeeper, if you are a hobbyist with just a few hives, you should seriously consider trapping pollen from your hives and feeding it back in times of pollen dearth. Natural pollen is superior to substitutes and trapping is fairly easy to do.
Some beekeepers don’t like to trap pollen because they fear that extra pollen foraging will cut into their honey production. Maybe yes, maybe no. But you have to ask yourself: Do you want healthy bees or do you want that extra jar of honey? Considering how difficult it is to keep bees healthy, and considering the price of replacement, a trap may be the answer.