Written by Amy Yarger, Butterfly Pavilion Horticulture Director

One of my favorite harbingers of spring is the golden currant bush (Ribes aureum). In April and May, this native shrub blooms with clove-scented golden flowers that attract many pollinators. One of the pollinators it feeds is our Hunt’s bumble bee (Bombus huntii), or as I like to call it, our “red-butt bee”. Bumble bees are a large (both in body size and diversity) group of native bees, with over 250 species worldwide. They are graceful, yet bulky fliers, and the loud buzzing you hear when you see one flying gives these bees their Latin name – “Bombus” means “a buzzing sound”.

Hunt’s bumble bees can be found throughout western North America, from Manitoba to Mexico, and its population is currently stable, although there is some evidence that it is declining like many of our native bees. Here in Colorado, this species is one of our most frequently spotted. Hunt’s bumble bee is distinctive with a yellow face and 2 red-orange bands on its abdomen. They are smaller than some of our other common urban bumbles, but have a long enough tongue to drink nectar from a variety of flowers. Their fuzzy bodies are the perfect pollen-catchers, and you can often see them dusted in pollen while carrying even more pollen on their thighs.

This time of the year, you may be lucky enough to spot the queen, who is almost an inch long. She’s the only one in her colony that overwinters, so she has to find enough food to not only keep herself going but to provision her future children. Since she might fly over a mile to find the perfect nesting site, that means visiting a lot of flowers to fuel up! Once she finds a safe place, she digs a burrow or re-uses another animal’s den to begin her family. Bumble bee colonies range in size from 50 to 400 individuals, but once her first worker daughters hatch, they will assist by building cells and gathering pollen and nectar. They are much smaller than their queen mother, almost by half, and you can see them from late spring until frost. Males are only present for a brief time, long enough to go on patrol for another queen to mate with.

Many bumble bee species are tough enough to live at high elevations and cold temperatures, but our Hunt’s bumble bee prefers the prairies and desert scrub at 6500 feet or lower. They also love gardens and are attracted to a wide range of flowering plants, including penstemons, columbines, bee balm, sunflowers, goldenrod and wild roses. Bumble bees are one of the few pollinators that can help you with pollinating your tomatoes and peppers. They have a special way of hanging on to flowers and emitting a special “buzz” that helps the flower to release its pollen – this is called “sonication”, the use of vibrations to effectively fertilize the female parts of the flower.

If you like these “flying teddy bears” as much as I do, there are many ways you can help them. Making sure you have plants in your gardens that bloom from spring to fall ensures they have the calories they need to carry out their life cycle. Another important thing to consider is leaving some areas without landscape fabric so that queens can start their nests. Finally, if you keep honey bees or know anyone who does, making sure the hives are healthy and have plenty of forage helps bumble bees like Hunt’s bumble bee. Hunt’s bumble bee is susceptible to some of the same viruses that affect honey bees, so healthy honey bees mean healthy “red-butt bees”, too.

After a long winter, is there anything better than sitting in the warm sun in the garden and enjoying the fragrance of flowers and the humming of the bees? Now you can relax, knowing that what you are hearing is the sign of a healthy environment and a fruitful summer to come.

Want to learn more about pollinators and how to help them? Contact Butterfly Pavilion’s horticulture department at habitat@butterflies.org!