A Unique Set of Skills: The Untold Story of the Native Bee
Many of you may remember being taught that honeybees were brought to the Americas by European colonists during the 17th century, and the importance of honeybees’ role in the pollination of crops and therefore, our food supply. Over the years, some paleontologists and entomologists have produced what they believe are fossils that show native honeybee species. However, the overall consensus among scientists is the former timeline.
Did you know that before the introduction of the honey bee, there were any number of native bees that were responsible for pollination of the native plant species in North America? According to the United States Geological Survey (USGS), of the approximate 20,000 bee species, 4,000 are native to the U.S. Only about 90% of the U.S. native bees have been identified.
Approximately 75% of the world’s native plants achieve pollination by way of animal contact, with native bees being the most efficient in this regard. While there has been much discussion over the recent decade or so regarding the importance of the honey bee and its diminishing numbers, native bees are responsible for pollination of most commercial crops in the U.S. Also, the overall bee population, not solely honey bees, has significantly declined. All continents other than Antarctica have native bee species, and these bees are responsible for pollination of approximately 80% of the world’s flowering plant species.
What do we know about our native bees? It’s complicated!
Bees native to the U.S. vary in size, shape and color, and somewhere between 20-50% of them are considered pollen specialists. As you can see, this large range just exemplifies how much we do/do not know regarding the specialized pollination of native bees. Native bee species have not been consistently or thoroughly studied over the centuries. Regardless, scientists know that a significant portion of native bees only retrieve pollen from (and thus pollinate), a single genus or species of plants (pollen specialists).
So, imagine this. There are native bees who specialize in sunflower pollen, some who specialize in fruit tree pollen or native flowering trees (like some native mason bees), some that specialize in plants of the genus Cucurbita (squash, pumpkins, gourds), some that specialize in native/wild peas and daisy species, some that specialize in blueberry or cranberry pollen, some that specialize in native flowering shrubs like azalea or rhododendron, etc.
Native bee species range from the Perdita minima (smallest fairy bee), which is the size a grain of rice to the large carpenter bees (genus Xylocopa) and bumble bees (genus Bombus). The smaller species tend to specialize in pollination of plants with flowers just as small. Considering their size, dwindling preferred native plants, and sometimes odd hours of foraging, some bees can prove to be quite elusive.
Bumblebees
Bumblebees are generally social, ground-nesting bees, and the most common type of bee. While the nest has a queen, worker bees and eventually drones, they live in groups much smaller than honey bees. They are known for their large furry bodies, black with yellow/orange stripes. There are over 250 species of bumblebees, and 49 of these in the U.S.
They belong to the Apidae family, the same family as honey bees, carpenter bees, cuckoo bees, digger bees, squash bees, orchid bees, and stingless bees. Bumblebees are pretty prolific pollinators, and can gain access to the pollen of plants that honey bees and some others cannot, due to the vibration related to its wing and thoracic muscle movement (buzz pollination). That’s some pec flexing! Isn’t it? Bumblebees are used in commercial greenhouses all over the world to pollinate tomatoes. Their lifespan is just short of a year. At the end of summer, the queen lays eggs which become both male and females. They breed and then the females which are destined to become new queens the following spring, sleep away safely over the cold months, while the old queen, workers and drones die.
Sweat Bees
Sweat bees (genus Lasioglossum) of the Halictidae family, the common smaller bee often recognizable by their curved wings, and dark metallic green coloring (though some species have yellow markings like the image above), get their names from one of their unusual feeding activities. They are known for hovering near humans in the heat, using their short tongues to drink/lick away their perspiration. Why? It’s the salt! It’s all about the salt! They need it for their daily bodily functions and it is important in larvae development.
Sweat bees are pretty indiscriminate pollinators (generalists) and pollinate a variety of wildflowers. Some species play an important role in pollinating alfalfa, as they have a way of forcing its flowers open to access the pollen, which is important for agriculture. These species are often called alkali bees, and they are ground-nesting bees that like salty mud. Farmers all over the world have used this knowledge to their advantage, keeping salty, muddy fields nearby.
Carpenter Bees
Another commonly heard of native bee, is the carpenter bee. Unfortunately, there is usually some wood damage when it is spoken of. The females bore through wood (prefer softer woods), forming tunnels that can be as deep as almost a foot, to lay the safe groundwork for her larvae and nutrition support. While the females are usually all black, the males are often mistaken as bumblebees. The visual difference is that carpenter bees typically have a smooth black abdomen vs. being furry all over like the bumblebee.
Like the bumblebee, it is an excellent pollinator, is a pollination generalist, and also uses buzz pollination to loosen pollen from the anthers of many plants. Unlike the bumblebee, carpenter bees are not social bees, and therefore do not have a hierarchy including a queen and labor roles nor do they live in large groups. They may also live up to three years vs. winter to fall like the bumblebees.
Mason Bees
The final bee that I would like to showcase is the mason bee (genus Osmia) of the Megachilidae family. Most bees in this genus are native. It gets its name due to how it forms its nests, utilizing mud and debris to form partitioned homes in cracks or crevices in stones or hollowed stems or pieces of wood. Mason bees are solitary bees much like carpenter bees. Most are a metallic green or blue.
There are over 300 species of this bee, and 140 of them reside in North America. One of the most important species in this genus is the orchard mason bee, Osmia lIgnaria, often referred to as the blue orchard mason bee. This species is a native bee and is best at pollinating fruit trees. Commercial fruit farmers provide bee housing (often hollowed tubes) to ensure these species have easy access to their cash crops. Mason bees live for about a year but are only active adults for about 3-6 weeks, long enough to mate, build and supply a nest, produce and secure eggs.
What is the outlook for native bees?
If invasive plant species or commercial agricultural selections decrease the availability of their target plants, the bees will die, as will eventually the plants, since pollination will decline significantly. Regardless of honey bees’ numbers, there are simply some plants that honey bees cannot pollinate. Honey bees are somewhat indiscriminate in their flower choices and their population can be aided by beekeeping. However, native bees, which are responsible for the majority of insect pollination, survive only if their preferred plants thrive or are in abundance.
What can we do to help?
We can do any of the following. We can grow and maintain wildflowers, native plant species, and a variety of fruit and vegetable crops. We can include possible nesting areas such as a relatively clear small ground area with sun exposure but safe from extreme wind and flooding, buy or build and install bee houses or nesting blocks in our outdoor space, include a safe water feature in your outdoor garden space, and do not use harmful pesticides when gardening. Below are some resources to help you along.
Gardening for Native Pollinators
Click here to get an easy reference bee resource for better understanding, and to help support and strengthen our native pollinators.