Bumblebee Economics

 

Common Eastern Bumble Bee, Bombus impatiens

Bumblebees are the other type of 'social' bee at Halibut Point, meaning that they nest colonially with a certain amount of division of labor, though nowhere near the extent of non-native honeybees.

Greg Morrow pointing to a grout pile crevice
where he observed bumblebees nesting last year

Their forays for pollen and nectar enable them to provision the colony for supporting brood increase throughout the warmer months. However they don't stockpile enough honey to get any members but queens through the winter. The fertilized queens go dormant in underground burrows and emerge to found new colonies in the spring. The series of roles, specializations, and identity changes that develop through the season from that single female founder makes for an interesting demographic study and a meditation on the interrelationship of individual and group survival.

Bumblebee wings in motion

Bumblebees are much larger than honeybees. Their ability to fly at all defied our minds' grasp until recent instruments determined that the bee's nearly 200 wingbeats per second are coordinated like helicopter blades in reverse-pitch semi rotary motion to deliver adequate lift and thrust. The neurological, muscular, metabolic, cooling and other intricacies of its flight, as understood by modern science, make fascinating reading.

Bumblebee foraging on a Bull Thistle flower

Bernd Heinrich in his Bumblebee Economics (1979) provides a whodunit spectrum of research adventures on how these creatures go about their busy bee-ness. Undoubtedly the revelations are satisfying to curious minds, to pure science, and to military engineers.

Bumblebee approaching a Yellow Thistle

The only fuel bees can use is sugar, which they derive from flower nectar. It also sustains the activities of the hive. The calories harvested from a foraging trip obviously exceed the calories used in flight. Bumblebees in the air are very efficient internal combustion engines with all the complexities of carburetion, heat transfer, exhaust disposal, load management, and navigational guidance of our manmade conveyance machines. Add to this circulatory, digestive, and other physiological systems, as well as the necessities of defense and propagation.

The intricate web of`interrelations among bees and flower is primarily governed by energy needs and payoffs. Throughout their evolution, bees have attempted to reap the maximum rewards from flowers. Flowers, on the other hand, have evolved to supply the least amount of food necessary to attract pollinators and to keep them moving from one plant to another for cross-pollination. The bumblebee's energy budget is of great significance in the insect's energy game with the flowers. The competition among plants for the pollinators' service, and among the pollinators for the plants' food rewards, decisively shapes the behavior, structure, and physiology of both plants and pollinators. Bernd Heinrich

Perplexing Bumble Bee, Bombus perplexus

Two other species of bumblebees occasionally found at Halibut Point.

Yellowbanded Bumble Bee, Bombus terricola