Native bees are important pollinators
What’s the buzz about pollinators? Pollination is a symbiotic relationship between an animal pollinator and a flowering plant. The pollinator receives a nectar or pollen reward and, at the same time, inadvertently transfers pollen from flower to flower or, in some plants, within the flower from the male stamen to the female stigma.
Bees, who spend most of their lives collecting pollen, are the main insect pollinators. You probably know that honeybees pollinate crops while producing honey for the hive and for you to enjoy.
Yet honeybees are not native to North America. Native bee species are significant pollinators in the region.
“Native bees are a valuable resource to our everyday lives as they provide a range of pollination services that enrich both our natural areas and our dinner plates,” according to Tiffanie Pirault of Virginia’s Department of Conservation and Recreation (DCR).
Here are some Bs on native bees:
Beneficial: One-third of the food on our plates is due to insect pollination. Individual native bees can be up to 70 times more efficient than an individual honeybee.
Although you may think of bees as stinging insects, it is only the bees that live in a colony or hive (e.g., honeybees, bumblebees and sweat bees) that would sting as a defense of their colony.
Sweat bees can be annoying and carpenter bees can be worrisome; however, the benefits of native bees as pollinators greatly outweigh any negative characteristics.
Botanical Specialists or Generalists: Based on their foraging habits, native bees are divided into two types. Generalists are about 80 percent of the total population, and the rest are specialists.
Specialists have developed over time to feed from only one, two or three kinds of plants. You may have noticed specialist bees in the early spring pollinating woodland ephemerals. For example, the pink pollen of spring beauty (Claytonia virginica) is necessary to the miner bee (Andrena erigeniae).
As a Virginian, try to grow plants that support specialists: willow (Salix); redbud (Cercis candensis); dogwoods (Cornus); winterberry (Ilex verticillata) and plants in the heath family (Ericaceae), such as blueberry bushes.
Burrowing and Borrowing: While honeybees live in a hive, native bees are typically solitary. Because many solitary bees live underground, it’s helpful to have a patch of dirt for burrowing.
Other solitary bees, such as mason bees, create nests in hollow reeds or holes in wood. In addition to laying eggs in small natural cavities such as woodpecker holes, mason bees will use handmade or commercial nesting boxes.
Bumblebees are native bees that live in a colony. An overwintering queen might borrow an unused rodent’s nest on the ground for her home.
Busy and Bustling: “Busy as a bee” is an appropriate expression. A bee can visit as many as 5,000 flowers in a single day. Surprisingly, bumblebees visit many more blooms per minute than honeybees. The average mass of pollen and nectar carried by bumblebees returning to the nest is around 25 percent of their body weight.
Big and Bitty: Honeybees are mid-sized bees. Native bees include large bumblebees (more than an inch long) and tiny bees that measure less than 1/8-inch long.
The zoology team with Virginia’s Natural Heritage Program at DCR has compiled a list of 450 Virginia native bee species so far. There are a dozen species of bumblebees alone.
Carpenter bees, mining bees, leafcutter bees and orchard mason bees are all Virginia native pollinators.
Buzzing: Big, beefy bumblebees are able to perform buzz pollination that is necessary for several flowering plants that keep their pollen on lockdown.
Bumblebees contract their flight muscles, producing strong vibrations directed on a flower’s anther to shake the pollen loose. Honeybees are unable to do this. We enjoy blueberries and tomatoes, for example, because bumblebees perform buzz pollination.
Blighted: Many North American bumblebees are experiencing steep population declines. For example, the rusty-patched bumblebee (Bombus affinis), once common in Virginia, has declined by roughly 80 percent and was added to the endangered species list in May 2017. Threats to bumblebees include parasites, disease, habitat loss, climate change, pesticides and invasive species, among others.
To “bee” pollinator-friendly:
Select a variety of native plants with a range of bloom-times.
Reduce lawn grass. Live with a few weeds and bare soil.
Be cautious when using pesticides. A chemical that kills a mosquito can also kill a bee. Read and follow all labeling.
Lela Martin is a Master Gardener with the Chesterfield County office of the Virginia Cooperative Extension. She is also co-chairman of the 2019 Bumblebee Jamboree.