LEARN: 1. What Are Native Bees?
1.2 Superior Pollinators
1.2 Superior Pollinators
Our flowers need bee diversity to be well-pollinated and grow more seeds and fruit.
For a plant to grow fruit and seeds, a flower needs to be fertilized by pollen. Pollen are small grains of genetic material produced by the male part of a flower. Wind-pollinated plants release their pollen in the air and the wind brings pollen to nearby plants. Wind pollination works well for lightweight pollen but many plants need help for moving their heavier pollen.
Many of our favorite foods that are rich in vitamins and nutrients rely on animal pollinators like bees to deliver their pollen. We can thank animal pollinators for about 1 in 3 bites of our food, and without them, we wouldn’t have coffee, chocolate, or cotton.
Pollination sounds simple but the way pollen is carried and how a bee behaves affects a bee’s pollination effectiveness. Flowers have to be visited multiple times to become well pollinated. A well-pollinated flower can grow fruit that is rounder, bigger, and sometimes even tastier than an under-pollinated flower.
- A single solitary bee can be as effective as hundreds of honey bees.
How Pollen is Carried: Dry & Loose
Social bees like honey bees carry pollen packed wet with saliva or nectar on the corbicula (also known as a pocket) of their hind legs, where it is wet and does not fall off as easily. Honey bees don’t want to drop any pollen during their long-distance flight (up to 5 miles!) back to the hive.
Solitary bees like mason and leafcutter bees carry dry, loose pollen on special scopa hairs on the underside of their bellies. Dry, loose pollen falls off easily at every flower visited with a clumsy but effective belly flop right where the flower needs pollination. Solitary bees can afford to leave the pollen dry since they only fly a few hundred feet from their nest in search of flowers.
Many plants need to be pollinated by pollen from another plant, this is called cross-pollination. Working alone as a rogue agent, the solitary bee meanders between flowers, visiting flowers that give off the best pollen and nectar signals. Their meandering behavior makes spring mason bees great cross-pollinators in fruit and nut orchards. The sophisticated honey bee is a meticulous and well-coordinated flower visitor often goes back and forth from the hive to the same branch on the same tree, which results in low rates of cross-pollination.
Worse Weather and Longer Days
Solitary bees are working alone and need to provide for their own nest chambers before their short lives are over. Solitary bees will begin to fly earlier in the morning and finish later in the evening. The social honey bee can afford to wait out bad weather while they feed on their stored honey. Spring mason bees emerge in weather about 10F degrees cooler than honey bees and they will fly in wind and light rain.
Some flowers have evolved special ways of ensuring that they get pollen from the right visitor. An excellent example is the alfalfa flower - when a bee lands on the lower petals, the flower opens and hits the bee on the head with pollen. Honey bees don’t like to open alfalfa flowers but our solitary summer leafcutter bees don’t mind at all. Our summer leafcutter bees are 15X better at pollinating alfalfa due to their behavior and how they interact with flowers.
Some flowers need to be shaken to release their pollen, this is called buzz-pollination and it’s another example of flower evolution. Honey bees are unable to buzz- pollinate but bumblebees and some wild bee species are able to buzz-pollinate flowers like tomatoes, eggplants, blueberries, and cranberries.
Some bees are better suited to pollinate certain crops and with bee diversity, we can ensure that flowers are visited often enough to grow better food. Every bee species behaves a little differently and each new flower visitor increases the chances that a flower is pollinated. An international study published in 2016 showed that adding pollinators to small farms increases crop yield by about 25%. As the world’s population grows we need to find sustainable ways to grow more food and gardeners can help by raising and supporting hole-nesting bees.