Category Archives: Bombus

Pollinate Your Plate Part 3: A Colorful Dinner

Pollinator Plate 3 Colorful Dinner

“Colorful Dinner” was part of a series of posters I made demonstrating what meals might look like with and without foods that benefit from animal pollination. Here are two of the bees that helped make that vibrant salad:

Bumblebees (Bombus spp.)
Bombus unk
Large, fuzzy bumblebees are used to pollinate tomatoes and peppers in greenhouses. Tomato and pepper flowers have special anthers (the male part of the flower) from which pollen can only be released by vibrating the flower. As an analogy, think of shaking salt out of a shaker. Bumblebees excel at creating vibrations to release this pollen in a way honey bees cannot. They unhook their flight muscles from their attachments and vibrate them when visiting tomato flowers. This type of pollination is known as buzz pollination.
Peponapis pruinosa front
Squash Bees (Peponapis pruinosa)
Squash bees are native to the Americas, and specialize on cucurbit pollen (winter and summer squash, and zucchini). Females build nests underground, usually beneath squash vines. Males patrol squash flowers looking for females in the morning, and rest in closed up squash flowers for the rest of the day.

Happy Dining!


Bumblebee Facts

I haven’t had time lately to put together an in-depth post, but I thought I’d share this poster I made to accompany a live bumblebee observation colony. Happy weekend!

bumblebee facts

Pollinate Your Plate Part 2: A Filling Lunch

Lunch food with and without ingredients that benefit from animal pollination.

Lunch food with and without ingredients that benefit from animal pollination.

What do cheese, butter, milk, and ice cream all have in common?

If you answered that they all require bee pollination for mass production, you are correct!

Although it may not be intuitive, the dairy industry relies on the production of alfalfa to feed dairy cows. This alfalfa is grown from seed, which can only be produced via bee pollination of alfalfa flowers:

alfalfa production

Due to alfalfa’s unique pollination mechanism, honey bees are not the best pollinators of alfalfa. For this reason, several other species of bees are managed commercially for alfalfa pollination, such as the alfalfa leafcutter bee (Megachile rotundata) and the alkali bee (Nomia melanderi). These bees are particularly dear to me since I study alfalfa pollination, so I am sure I will be writing more about them in the future.

a female alkali bee and the entrance to her nest Photo by James Cane of the USDA-ARS.

a female alkali bee and the entrance to her nest Photo by James Cane of the USDA-ARS.

Putting Peppers and Tomatoes on your Pizza: The Humble Bumblebee

The interior of a commercial bumblebee colony.

The interior of a commercial bumblebee colony.

As I mentioned in a previous post, tomatoes and peppers also have unique requirements for pollination. When grown outside, the wind can naturally shake loose some pollen from the tomato or pepper flower, but in the greenhouse where there is no wind, domesticated bumble bee colonies are used to pollinate these crops.

An Osmia a day keeps the doctor away:
applesWhen we talked about breakfast, I mentioned that a solitary bee called the Blue Orchard Bee can help pollinate almonds. Orchard bees, as their name suggests, also visit a variety of fruit trees, such as apples. Even though we don’t grow apple trees from seed, in order for apple fruits to develop the flower must be cross pollinated with another apple or crabapple variety. In the Eastern U.S., some researchers are experiencing with using orchard bees to commercially pollinate apples.

Thanks for reading this week’s post! Please come back next week to learn more about how pollinators bring color to our plates.

Plight of the Bumble Bee Part V: What I’ve Learned

Time to wrap up my Bombus segment. I hope that you enjoyed reading about the bumble bees and maybe even learned a couple things. I certainly did. A quick recap, a la “what I have learned:”

1. Our Southern Neighbors

In Plight of the Bumble Bee Part III: Not-So-Impossible-Giants, I posted this photo of a beautiful bumble bee I saw on a trip to Patagonia:

La Gigante Imposible (c) 2012 MRS


I mentioned that, while I was sure this bee was in the genus Bombus; (the bumble bee genus), I didn’t know which species it was.  Well just last week I stumbled across an article (incidentally also titled Plight of the Bumblebee so I guess I’m not as clever as I thought) that says there is only one bumble bee native to Patagonia, Bombus dahlbomii. This bee is the largest bumble bee in the world.

Our poor Southern neighbor appears to be suffering from similar issues to her North American cousins (see my post The Plight of the Bumble Bee Part IV: Pandora’s Bee Box, as described in this Science article.

2. Tricky Bee ID

The Mystery Bee Among the Blossoms

I was very flattered to receive a site visit from the highly esteemed Robbin Thorp of UC Davis, who happens to be the bee identification guru. He informed me that the conclusion I drew from my Is it a bumble? quiz, that the bee in question was most likely Bombus impatiens, was incorrect, and that the mystery bee was actually a male Eastern Carpenter Bee, Xylocopa virginica. The reason that the bee did not have any scopae (pollen collecting hairs) was because this individual was, in fact, a male (see The Dastardly Deeds of Male Bees, and while the male Eastern Carpenter Bee is often mistaken for the Common Eastern Bumble Bee, Bombus impatiens, certain aspects of the leg morphology can be used to tell them apart (for those of you keeping score, the hind tibia is swollen and shorter than the basitarsus).

In this blog, I will probably not be able to give positive identifications to a lot of the live bees I photograph. This is because I am still learning how to identify bees, and even for bee identification gurus, much of the time bees are nearly impossible to identify on the wing (the specimen must be taken for examination under a microscope). So I am always grateful to those wiser than I who are around to correct my mistakes. Thank you, Robbin Thorp!

Tune in next time for more photos of bees, large and small.

The Plight of the Bumble Bee Part IV: Pandora’s Bee Box

Nate Pope, Bee Biologist Extraordinaire

Illuminated by a single red light, Nate bent over the open cardboard box, alternately counting objects with a clicker and manipulating objects with gloved hands holding a long pair of tweezers. A swelling chorus of low buzzing made me more than a little nervous. Even though I knew that the  contents of the box couldn’t escape, I kept seeing phantom angry, swooping objects in the darkness.

In the above photo, Nate is removing pollen stores from a bee nest to see how much they ate this week (thus the gloves, long tweezers, and angry buzzing). Bees’ eyes are not designed to see red, so Nate works under red light to keep the bees from flying away when he opens the box.

From the title of the post, you’ve probably guessed what kind of bees Nate is studying.

Bombus impatiens colony. Please excuse the poor photo quality!

This is a domesticated colony of the Common Eastern Bumble Bee, Bombus impatiens. It is the most common bumble bee encountered on the east coast of North America from Ontario, Canada to Florida, USA.

By far the largest colony member, the queen perches protectively over a profusion of pots in which food (pollen and/or a thin watery honey) is stored, and larvae are raised. The queen is surrounded by smaller worker bumble bees. Bombus impatiens typically build underground nests.

Alternative Pollinators

(c) David Besa 2005

Despite their widespread use as agricultural pollinators, honey bees are often surprisingly bad at their jobs compared to native bees. Tomatoes, for example, require sonication, or buzz pollination. This involves producing large vibrations to shake pollen free from pollen-holding structures in the plant: something that bumble bees do quite well, but honey bees cannot. Farmers that grow tomatoes in greenhouses can therefore purchase colonies online, which are shipped via snail mail in cardboard boxes. The bumble bees are released in the greenhouse to pollinate their tomato plants to ensure a robust yield.

The Dark Side of Globalization: Tiny Smallpox Blankets

Most of us Americans have heard stories in school about the introduction of smallpox by European settlers the Americas. Although the European settlers had some natural resistance to the disease, the indigenous peoples of the Americas, who had never encountered the disease, had no immunity. The disease ran rampant in these communities, killing millions.

Parasitic mites, such as these tracheal mites infecting the air passages of a honeybee, can be spread from one bee to another similarly to pathology in humans.

In the past decade, bumble bees have also been in in decline in the Americas. Although there are multiple causes for these declines, including habitat destruction and agricultural pesticide use, diseases transported along with Bombus impatiens colonies used for greenhouse pollination are a major culprit. Many of these bees are raised in the Old World, where they pick up diseases such as tracheal mites (bugs that live in the bee equivalent of lungs) and transport them to the New World. New World bumble bees have not evolved defenses to these diseases because, like the indigenous peoples of the Americas, the bees have never been exposed to them before. Tragically, once these diseases get out of the bee box, it is almost impossible to reverse their spread through native bee populations.

Bombus franklini, photo courtesy of Robbin Thorp. Click the picture to view the Red List Profile.

One of the casualties of the bees-in-a-box is Bombus franklini, a species discovered by UC Davis Professor Emeritus Robbin Thorp. Thorp’s research showed that from 1998-2006, sightings of B. franklini decreased drastically. Only one bee was sighted in 2006, and as far as I know, there have been no more sightings of Franklin’s bumble bee since.

For more information on how to help our sisters the bumble bees, please check out the Xerces Society’s Bumble Bee Conservation Initiative.

Answer to Last Week’s Quiz

Thanks everyone who participated in my “is it a bumble bee” quiz last week! For those of you who are interested, I do think this is a bumble bee. Here’s my logic:

(1) Overall appearance: it appears to be a large, fuzzy-bodied bee, which makes it either a carpenter bee or a bumble bee.

(2) The Wings: As I mentioned (although perhaps confusingly) in my last post, bumble bees fold their wings one over the other, whereas carpenter bees keep them to the side. This bee has its wings folded over the back.

(3) The legs: This isn’t the greatest picture, but it appears that part of the hind leg is shiny (meaning smooth, not hairy) and widened compared to the other legs. This could be an empty corbicula (something that only bumble bees and honey bees have). On other female bees, we would expect this area to have long hairs and/or be similar in shape to the other legs.

The Plight of the Bumble Bee Part II: What Gives a Bee its Bumble?

The bumble bee may be the most potent weapon in my arsenal when it comes to convincing people of the existence of bees other than honey bees. The conversation usually goes something like this:

Person at Party Feigning Interest in My Research: (after me explaining that I do not study honey bees) Oh wow, that’s so interesting. I always thought there was only one kind of bee.
Me: You probably know about more kinds of bees than you think. Like, what about bumble bees?
PPFIMR: …Oh yeah.

So what about bumble bees?

Bees on the Wing

Mystery Bee Among the Blossoms

Mystery Bee Among the Blossoms (c) 2012 CRT

My mom, who lives near Washington, D. C., sent me this photo of a bee visiting some of the famous Japanese cherry blossoms that encircle the Tidal Basin. She wanted to know if it was a bumble bee. With only a wing, an abdomen and part of a leg to go on, it’s hard to say, but let’s go over the evidence of what constitutes a bumble bee:

There are 250 described species of Bombus (bumble bees) worldwide. They are medium-sized to large, robust, furry bees. They can be distinguished from the similarly-large carpenter bees (Xylocopa) because carpenter bees generally have shiny, not furry, abdomens and hold their wings out to the side at rest (bumble bees neatly fold one wing over the other).

But the best way to tell if a bee is a bumblebee? It’s on the legs.

When female bees visit flowers, they have to collect pollen to feed all the little mouths back at the nest. Most females use long, shaggy hairs called “scopae,” often located on the hind legs, that look kind of like retro legwarmers.

Honey bees and bumble bees, however, collect pollen on special smooth, flattened structures called “corbicula.” The best way to think of a corbicula is as a tiny shopping basket that the bee fills with pollen to take home. Here’s a photo of a bumble bee’s corbicula from

Beatriz Moisset 2005

[an aside about corbicula: sometimes on really hot days during the field season, whenever I see a bumble bee, I start singing a song I like to call “Corbiculi, Corbicula,” which is sung to the tune of (surprise) “Funiculi, Funicula”. Hey, it helps keep me sane…]

So why am I confused by the Mystery Bee Among the Blossoms?

After I told my mom I wasn’t sure what kind of bee this was, she sent me this photo:

Want to test you bumble bee knowledge? Here’s a little quiz for you folks at home: is this bee a Bumble Bee or not?

Answer coming up next week…