State of the Species: American Bumblebee (Bombus pensylvanicus)

Written by: Carol D. Gaskamp, Guest Contributor

I’m bringing home a baby bumblebee; Won’t my mama be so proud of me?

I’m bringing home a baby bumblebee; Ouch, it stung me!

The lyrics to this nursery rhyme song may be the introduction many have to the stately bumblebee. Bumblebees are important pollinators that live in grasslands and open spaces.

The American bumblebee is known for its comparatively large size, fuzzy yellow and black stripes, and loud buzzing sound. The size of the bee allows it to fly in stronger winds and light rain. The bumblebee has an erratic flight pattern that makes it a useful pollinator across row crops – and inspired Rimsky-Korsakov to compose the Flight of the Bumblebee. They can also buzz pollinate plants that need to be shaken to release pollen, such as tomatoes. Bumblebees have long tongues used to gather nectar from tubular flowers. They can fly in low light, which enables them to collect nectar and pollen from plant species that release nectar in early morning hours.

Bumblebees are social insects that live in colonies, and do not migrate. The life cycle of the colony and bee is a year, starting in the spring when a fertilized queen bee emerges from hibernating in an underground nest. The queen finds a new nesting site either in the ground using an abandoned rodent nest, or above ground in grass tufts, rock piles, old bird nests, or a tree cavity. The queen initially lays 8-12 eggs and then collects pollen and nectar to feed the larvae. After 14 days, the larvae become pupae for several weeks to finish development. New bees become the worker bees to take over pollen and nectar collection, and the queen lays more eggs. Most offspring at the beginning of the season are female worker bees that collect food, take care of the larvae and pupae, and defend the nest – yes, they sting! In mid to late summer, males and new queens are produced. The queen’s eggs can be either queens or workers, depending on the amount of food the larvae are fed. Worker bees produce eggs, but these eggs are not fertilized and become male bees. In late summer, the new queens and males leave the nest, mate, and the queens then hibernate underground. The old colony dies off, and the cycle begins again the next spring.

Once common, the American bumblebee population has declined to the point of no longer being seen in some northern parts of the bumblebee range. The International Union for the Conservation of Nature estimates an 89% decline in the American bumblebee population, and was listed as a vulnerable species in 2014. The loss of open spaces and grasslands due to urbanization and the agricultural use of pesticides have contributed to the decline of the bumblebee population. Other causes of the population decline include diseases from honey bees and domesticated bumblebees, climate change, drought, extreme temperatures, fires, and floods.

Efforts to conserve the American bumblebee include:

·      Monitoring the species for population trends

·      Identifying and controlling pathogens that infect the bees though scientific research

·      Avoiding the use of pesticides near areas that the bees use for foraging, nesting, and hibernation

·      Restoring and protecting grasslands, and create new grassland habitats

·      Promoting the use of nitrogen-fixing fallow fields in farmland management

The Coastal Prairie Conservancy’s conservation efforts on the coastal prairie help preserve and restore the grassland habitat and native plants that the American bumblebee needs to survive and thrive in Texas. You can also help the the population by planting native flowers and pollinator gardens that provide the nectar and pollen essential for bumblebee survival. Together, we’ll protect this mighty little pollinator that calls the coastal prairie home!

What can volunteers do?  Helping with grassland restoration is huge!  By participating in activities such as seed collecting, Stewardship Saturdays, the Great Grow Out, and the annual Putting Down Roots event, volunteers help ensure that grassland habitats used by American bumblebees on the coastal prairie stay healthy and resilient.

Carol D. Gaskamp, guest contributor, is a member of the Gideon Lincecum Chapter of Texas Master Naturalists.