Mad About Science: Idaho native bees

By Soncirey Mitchell
Reader Staff

When asked to name three characteristics of bees, most would say that they’re yellow and black, they live in a hive and they make honey. For the majority of the world’s bees, all three of these claims are incorrect.

With more than 20,000 species around the globe, bees come in shades of brown, blue and green — including Idaho’s sweat bee — and only Afro-Eurasia honey bees make honey. Bees evolved from carnivorous wasps but adapted to feed on pollen and nectar when flowering plants first appeared approximately 125 million years ago, according to Bee Basics: Introduction to Our Native Bees by Dr. Beatriz Moisset and Dr. Stephen L. Buchmann. Pollen is high in protein and, unlike bugs and spiders, doesn’t mind being eaten.

There are no honey bees indigenous to North America. Europeans cultivated them as livestock and brought them along while colonizing the continent, where they escaped domestication and became the poster children for bees everywhere.

Honey bees are important agricultural pollinators; however, they’re second-rate when it comes to pollinating North American plants like cranberries, blueberries and pumpkins. Idaho Fish and Game estimated in Wildlife Express: Bees of Idaho that, when pollinating cherry trees, 10 indigenous mason bees can do the work of 60 honey bees because the species evolved side by side and therefore adapted to one another.

According to Idaho State University, of the seven bee families in the world, five live in Idaho: Andrenidae, Apidae, Colletidae, Halictidae and Megachilidae. It’s unclear how many individual species inhabit the state — estimates range from 400 to 700 — which, regardless, is a large variety, likely due to Idaho’s diverse ecosystems.

There are approximately 4,000 species of native bees in the U.S., though that number could be higher. Bees have a large range of behaviors, sizes and colors, making them difficult to catalog. The Perdita minima of the Sonoran Desert averages a little less than two millimeters in length, according to the U.S. Forest Service — about the size of a grain of white rice.

Most native bees are solitary and make their nests in hollowed-out stems, rock crevices, dead wood or holes in exposed dirt, rather than in hives or colonies. Solitary bees may build their homes near one another, but they won’t share resources or care for each other’s young.

As their name suggests, Idaho mason bees (Osmia bucephala) use mud to construct sturdy walls within their nests to protect their eggs from parasites. Leafcutter bees (Megachile subnigra) have a similar practice using pieces of leaves.

Female solitary bees not only build their own nests, they also stockpile all the necessary food to feed their brood into adulthood — a phenomenon known as “mass provisioning.” Most mix dry pollen with nectar and saliva to form a stable paste, which they store in each chamber of their nest alongside the individual eggs. The saliva is believed to protect the mixture from bacterial and fungal infections, according to Bee Basics.

Bumble bees (of the genus Bombus) are an exception. Of the 27 species present in Idaho, most live in colonies built underground in abandoned mouse holes or similar burrows. Some species have become “cuckoos,” and lay their eggs inside others’ nests rather than build their own.

Though cold-blooded, bumble bees can keep their eggs warm by sitting on them and vibrating their flight muscles to generate heat. This ability also allows them to fly in cold weather, making them a valuable pollinator in early spring. Generating heat requires large amounts of energy, so bumble bees rely on early-bloomers, like willows and maples, for food. According to Wildlife Express, these bees will also cling to a flower and beat their wings — a phenomenon known as “buzz pollination” — to efficiently shake pollen onto their hairy bodies.

Like honey bees, bumble bees usually have one queen and a few hundred female workers. The queen waits until late summer to lay male eggs alongside the future queens so that they can mate shortly after emerging. Once mated, the newly hatched males promptly die — along with the rest of the colony — leaving the new queens to hibernate and start anew in the spring.

Bees are an integral part of life on Earth; but, due to factors like climate change, disease and pesticides, many species are threatened. Everyone with access to outdoor space can take part in conservation efforts to help native bees.

Gardeners should avoid pesticides if possible — especially neonicotinoids, which poison a plant’s sap and nectar. Never spray a flower directly when using pesticides.

Clover and wildflowers are a great food source scattered throughout a lawn. Yes, even dandelions help.

Leaving a few bare patches of dirt around the base of plants provides shelter for ground-dwelling bees, and supplying a shallow source of water or mud keeps pollinators hydrated and gives them additional nesting material.

To be more involved in bee conservation, plant a pollinator garden with blooms of various shapes and sizes to attract different species of bees. Use native plants that flower at different times throughout the year to ensure a lasting food supply rich in nutrients.

Stay curious, 7B.