CO-Horts Blog

Thursday, May 19, 2022

The Role of A Bumble Bee

The Role of A Bumble Bee
By CSU Horticulture Agent, Linda Langelo

A great northern bumble bee (Bombus fervidus) foraging on catmint (Nepeta spp.) at the Lima Plaza Pollinator Demonstration Garden in Araphoe County, Photo: Lisa Mason

According to the Xerces Society, bumble bees pollinate wild flowering plants and crops. They do not depend on flower type to survive. With some plants, it is not that way. There are some rare plants that depend on a bumble bees such as the native monkshoods and lady's tresses orchids. Bumble bees are the only known pollinator of potatoes worldwide.

Other flowers the bumble bee pollinates are snapdragons, mints, orchid and peas. According to the Brooklyn Botanic Gardens, flowers pollinated by the bumble bee must have a sturdy lip, apron or heel for a landing pad. When the bumble bee lands on monkshood it opens the flower. The petals pop open and the bumble bee clambers over the male and female parts collecting pollen at its feet while reaching with its head to the nectaries in the hood of the monkshood flower. Once it flys to the next monkshood, seeds are pollinated, and the species is ensured continuation. 

One of the most common bumble bees in Colorado, the Hunt's bumble bee (Bombus huntii) forages
on a linden tree (Tilia spp.) in the Araphoe County. Note the ball of pollen and nectar she has collected
in her pollen baskets called corbiculae. Photo: Lisa Mason

What would the world look like without bumble bees as pollinators? There would be several plants missing from the world. However, there is some recent research according to in an article Bumble Bees Have Learned to Hack Plants by Nina Pullano. Pullano is referring to the hacking of a plant when a bumble nibbles on the leaves of a plant that is not producing flowers. This may damage the plant by stimulates flower growth. Plants not in flower can bloom up to a month earlier. This behavior was found in a lab at the University of ETH Zurich by researchers Mark Mescher and Consuelo De Moraes. They found that this also happens in the wild. This is a particular characteristic that only bumble bees possess. Researchers are uncertain if they have in their saliva that causes plants to flower. But it seems we can say that bumble bees are adapting to climate change. But what will they be able to tolerate as the climate continues to change remains to be seen?

Bumble bees still need our help. Creating gardens with diverse flowers and the right habitat for bees is essential. Here is a brief list of the trees that benefit bumble bees:

  • Oak
  • Black Locust
  • Elms
  • Wild Cherry
  • Maples
  • Honey Locust
  • Plum
  • Peach 
  • Apricot
  • Lindens
The following link is a Colorado State University Fact Sheet Attracting Native Bees to the Landscape: Https://

Bumble bees need pollen because it is a great source of protein. They also need nectar which provides carbohydrates. The more diverse type of plants in our landscapes, the more opportunities we give the bumble bees the chance to obtain what they need when they need it. Having plants that bloom early to late season ensures the success of keeping bumble bees going. 

The following link is a Colorado State University Extension Fact Sheet Creating Pollinator Habitat: Https://

A Nevada bumble bee (Bombus nevadensis) foraging on a Rocky Mountain Bee Plant (Cleome serrulata) in Gilpin County. Photo: Lisa Mason

1 comment:

  1. Please insert the correct photo - that is no Linden blossom!