How flowers survive social distancing
Amid these times of distancing from other people, perhaps we can learn from the intricate relationships in nature, including the one between flowers and the bees who pollinate them.
Since plants permanently “shelter in place,” they have had to develop the means to reproduce. Pollination is the symbiotic relationship between plants that are fertilized and pollinators that do the fertilizing (and are rewarded with pollen and nectar).
Although birds, some mammals and many insects, including ants, flies and beetles, inadvertently move pollen through close contact, bees are the most prolific pollen carriers. As bees move from flower to flower, they spread pollen to many plants, a phenomenon called cross pollination.
Cross pollination ensures genetic diversity and the ability of plants to adapt to changing conditions. Even though about 10% to 15% of flowering plants are predominantly self-fertilizing, bees play a part here as well by moving the pollen within a single flower.
After a flowering plant is fertilized, fruit can develop. About one-third of the food we eat is a result of pollination. Using some “buzzwords” and concepts from today’s headlines in other contexts may help explain the pollination relationship.
Flowers produce pollen
Much as a grocery store sells food, cone-bearing and flowering plants produce pollen. The powdery, sometimes sticky, substance is often yellow, but pollen can be a rainbow of colors depending on the plant.
In flowering plants, pollen is produced in the anthers, part of the stamen within the flower. Each pollen grain contains the “male” reproductive cell that can fertilize the “female” part of the flower (stigma, part of the pistil). Pollen is moved either by the wind or by insect or other animal pollinators who contribute to community spread.
Bees collect pollen
Think of the foraging worker bees as the InstaCart essential employees who pick up food from many groceries and deliver it. Bumblebees (called “bumbabees” by my two-year-old grandson) are some of the more than 3,500 species of native bees that provide pollination, especially in our own yards. Honeybees, although not native, perform more than 80% of all pollination of cultivated crops.
Flowers entice bees
Flowers must make themselves attractive to the bees who assist them. Bees are most attracted to the neon signs of bright white, yellow and blue flowers as well as flowers with contrasting ultraviolet patterns. Blue-flowering plants appealing to bees include salvia, Russian sage, lavender and vitex. Extra-tempting benefits include fresh, mild and pleasant odors.
Honeybees unintentionally collect pollen on their hairy bodies, including their eyes. To groom themselves, bees use their legs. Researchers at Georgia Tech found that a bee could shed about 15,000 pollen grains in two minutes as it brushed itself clean — talk about a super spreader!
Bees move a portion of that pollen to special structures on their hind legs called pollen baskets. You may see foraging bees returning to the hive with bright yellow balls of pollen hanging from these pollen baskets.
Pollen provides protein
Just as humans eat protein, bees feed on floral pollen as their source of protein, fat, vitamins and minerals. Bees refine the chemical nature of pollen, turning it into beebread (also known as perga) and then converting that into royal jelly.
Beebread starts with the fresh pollen gathered by honeybees, mixed with nectar and digestive juices, packed in the empty comb cells in the hive, and sealed with a drop of honey. The beebread remains stable indefinitely as a protein-rich food to feed the larvae.
Royal jelly is secreted from glands in the heads of worker bees and is fed to all bee larvae, whether they become drones (males), workers (sterile females), or queens (fertile females). After three days, the drone and worker larvae are no longer fed with royal jelly, but queen larvae continue to be fed it throughout their development.
Nectar is a sweet reward
Nectar, a sugary liquid produced in plant glands called nectaries, attracts and rewards pollinators. Worker bees drink the nectar by sucking it with their tongues, and store additional amounts in a pouchlike structure called a crop (also known as a honey stomach or honey sack), which is different from their food stomach. Nectar is a bee’s main source of carbohydrates, water and essential minerals.
And, of course, bees also convert nectar into honey. Foraging worker bees fly back to the hive and regurgitate the nectar to quarantined house bees, passing it on from bee to bee for about 30 minutes until it gradually turns to honey.
House bees mix the nectar with enzymes and deposit it into a honeycomb cell, which is like a wax jar, where it remains exposed to air for a while, allowing some of the water to evaporate.
The bees help the process by fanning the open cells with their wings, as the honey becomes stickier. The cell containing the resulting honey is later capped with beeswax and kept for future food for the drones and worker bees. It takes at least eight bees all their lives to make one teaspoonful of honey.
Protect the workers
To protect bees on the front lines, reduce or eliminate your use of pesticides. Flatten the curve of bee deaths. Celebrate National Pollinator Week from home from June 22 to 28, 2020. For more information, go to pollinator.org.
Although Bumblebee Jamboree 2020 has been cancelled, mark June 19, 2021, on your calendar for next year’s local pollinator event.
Lela Martin is a Master Gardener with the Chesterfield County office of the Virginia Cooperative Extension.