Where Have All the Bumble Bees Gone?

The population of bumble bees has declined disastrously, according to a just-published study in the Proceedings of the National Academy of Science. The dramatic drop in population is especially being seen in domesticated bees who are useful in agriculture. 

Bumble bees have long tongues, high-frequency buzzing (which helps release pollen from flowers), and a large body, all of which makes them excellent pollinators.(USA Today via the Tucson Citizen) They pollinate many native wildflowers and crops such as cranberries, blueberries, raspberries, squash, melons, and hothouse tomatoes. (University of Minnesota) In the US, bumble bees pollinate some 15% of all crops grown in the nation, for a total of about $3 billion.

University of Illinois entomology professor Sydney Cameron, who led the research, analyzed historical records going back to the late 1800s and repeated surveys of about 400 sites in the US to study the geographic distribution and genetic diversity of eight species of bumble bees. The researchers put together a database of more than 73,000 museum records, and compared these with a  current sampling based on intensive national surveys of more than 16,000 specimens.  

As noted in Science Daily, the researchers found that ‘the relative abundances of four of the eight species analyzed have declined by as much as 96 percent,’ while the geographic ranges of the species shrunk by 23 to 87 percent. Even more telling was that some of these changes have occurred in the last two decades. That is, in the past 20 years, four species of bumble bees have all but shrunk in their populations to the point of being non-existent.  

Declining populations of bumble bees lead to lower genetic diversity than in bumble bee species with healthy populations. And, populations with lower genetic diversity are more likely to be infected with a deadly intracellular parasite that has affected some species in Europe, nosema bombi—this fungus has been suggested as a reason for the declining bee populations. 

In an article about her study in the January 6th News-Gazette, Cameron noted that ‘people should be aware of the decline as a loss to nature and to the agricultural industry. Why these significant changes in this country’s bumblebee population have occurred is open to speculation. Some factors that Cameron note are climate change (which appears to account for the declines in some bumble bee species in Europe); habitat loss; and the above-mentioned parasite, nosema bombi
(The decline in the bumble bee population is a separate issue from honeybee colony collapse disorder.)

Cameron encourages people to ‘plant native species that can provide habitat for the big bees’ (here is a list of some native plants in California). 

So forget about those jokes about killer bees—- it’s really that something is killing the bumble bees.

Photo by steve p2008.

216 comments

Bonnie N.
Bonnie N.5 years ago

While I could live with out many of their more aggressive relatives (due to threat of anaphylactic shock), I always loved the bumble bee - they never bothered anyone, just went about their business, and were quite happy to ignore me - even though I loved watching them fly (they ARE NOT supposed to be able to! How do they get those bodies off the ground, darn it!). I haven't seen one in I don't know how long... I will miss them if they go away....

Celeste W.
Celeste Watson5 years ago

People, people. One day, all of us who were paying attention to all these seemingly disconnected signs of trouble are going to realize that we are looking at the beginning of the end of the current homosapien reign. It's already in motion, and I don't believe it is stoppable now ... notice how many more of these things are happening now, breakdowns in ecosystems ... it's now gotten enough momentum to be visible. We might've stopped it when it was still invisible, had we done the right thing rather than the most profitable thing, or the most resource-hogging thing ... but no more. I am not an 'end of the worlder' -- the planet itself will survive, but we have absolutely done enough to all the systems that must be in order to maintain the species at the top (us) that the next 'bottleneck' in human evolution is at hand. We just need one superbug, one supervolcano (like that under Yellowstone, 40 thousand years overdue for eruption), one large asteriod, and it's over for the majority of us for a long, long time. Things only look diverse to us now because we don't know what they looked like before written language.
Observe the mice plagues in Australia, brought on by giant monoculture ... before it ends and they die back, things get desperate, smelly, violent. We are larger, smarter, but subject to all the same natural laws. Hear me now, believe me later. It's already begun.

Sheila Lindsay
Sheila Lindsay5 years ago

No shortage of Bumble Bees here in Scotland. In fact, I have noticed an increase in the Bumble in the past two to three years .... I see lots of them .... but have noticed a fall in the sightings of the Honey Bee.

erinn p.
erinn p.5 years ago

fuzzy little bumbly bees :(

erinn p.
erinn p.5 years ago

fuzzy little bumbly bees :(

Kita Sharpig
Sian A.5 years ago

Very sad. These days I'm surprised if I see a bumble bee alive.

Betsy M.
Betsy M.5 years ago

Go native, plant wildflowers! It provides food & habitat for the bees (butterflies, birds, etc.) and entertainment & beauty for you.

Khat Bliss
Past Member 5 years ago

Watching a bumble bee is one of life's "little" pleasures. Just thinking how important they are, how big they are ....reminds me of when I was a child, back when there were no cell phones, computers..etc...the big thing of the day was for your mother to give you a cleaned out mayonaise jar and lid with holes, and you caught the bumble bee with stealth, mosting on the flower it was on....then just watched it for awhile and just thought about life, the bees etc...then...the exciting part...you opened the lid and let it go and ran screaming because that was the miracle of it...ah...times were simple then. Technology, Monsanto...are we really "advanced"? Hmmmm, I wonder?????

neil a.
Neil A.5 years ago

We should start worrying when the decline was 5% not 95% people seem so selfish & unfortunately breed faster than Rabbits! why would anybody other than a selfish person use herbicide on their lawn, if it is green OK , mine looks good with clover,violets & even some grass also daisies & even jonquills I did dig out the Bamboo & confined it. The very large blue black bees are fun to watch on my Wisteria flowers which will flower in less than a month, they have races round it as well. I see bees all the year round here & it is such a pleasure.

Greg Gilbert
Greg Gilbert5 years ago

Bees may be the canary in the coal mine.

As a first step, if everybody quit using pesticides on their lawn it would cut the pesticide load in our environment significantly.