Lynn Kimsey, director of the Bohart Museum of Entomology and UC Davis professor of entomology. (Photo by Kathy Keatley Garvey)

No? Probably can't due to the COVID-19 pandemic, but at least we can honor them every March 19 on Taxonomists' Appreciation Day.

Basically, taxonomy is the science of describing, naming, defining and classifying organisms, both alive and extinct. Each species is part of the tree of life. 

The Bohart Museum of Entomology at the University of California, Davis, is among those celebrating this special day.

"Basically we have eight taxonomists, all working on different groups of wasps, bees, flies, moths and beetles," said Bohart Museum director Lynn Kimsey, a UC Davis professor of entomology who identifies thousands of insects for scientists and the public alike. Plus, spiders, ants and millipedes!

"Clearly we don't really need any taxonomists for things with backbones and maybe not leaves, but invertebrates are so diverse and mostly so small you can't sight ID them; not even with a microscope. In addition, perhaps as much as 50 percent of the invertebrates are undescribed and a much higher percentage, like 99 percent, have never been sequenced. So we do DNA."

The Bohart Museum, home of nearly eight million insect specimens collected from around the world, is also celebrating its 75th anniversary this year. It was founded by noted entomologist and UC Davis professor Richard "Doc" Bohart (1913-2017). Bohart was Kimsey's major professor.

Want to know the common and scientific names of insects? The Entomological Society of America maintains a Common Names of Insect Database, described as "an essential reference for anyone who works with insects. It includes more than 2,000 common names and is searchable by common name, scientific name, author, order, family, genus, and species."

For instance, type in "bumble bee" (it's two words) and you'll get the order Hymenoptera, family Apidae, and the genus Bombus, among other information.  Search for "California bumble bee" and you'll get "Bombus californicus." By the way, search for "bumblebee" and "honeybee" and you'll get "cannot be found in the database." That's because they are two words: "bumble bee" and "honey bee."

The ESA database is a great scientific database and one that we should celebrate today--and every day--just like the dedicated taxonomists who pore over the organisms, describing, naming, defining and classifying them. 

Happy Taxonomists' Appreciation Day!  

Seen any bumble bees lately?

No? Me, neither.

It's almost the first day of spring, and bumble bees are as scarce as the proverbial hen's teeth. (Hens have no teeth, y'know.)

We've been watching our nectarine tree bloom. It's drawing honey bees, but no bumble bees. 

Back on March 18, 2018, we spotted a number of bumble bees, including Bombus melanopygus, also known as the black-tailed bumble bee. This is one of the 27 species of bumble bees in California. We frequently see the yellow-faced bumble bee, Bombus vosnesenskii, and sometimes Bombus californicus, aka the California bumble bee.

Our March 18, 2018 "poster child" on our nectarine tree, Bombus melanopygus, appeared to be nesting nearby, due to her frequent visits. 

National Public Radio reported on Feb. 6, 2020 that bumble bees are declining because of the extreme heat: "Extreme temperatures are driving a dramatic decline in bumble bees across North America and Europe, according to a new study, in yet another way climate change is putting ecosystems at risk.

"Researchers looked at half a million records showing where bumble bees have been found since 1901, across 66 different species. They found that in places where bumblebees have lived in North America, you're about half as likely to see one today. The decline is especially pronounced in Mexico, where bumble bees once lived in abundance."

Pesticides and habitat loss are also key factors. Says National Geographic in a Feb. 6, 2020 article titled Bumble Bees Are Going Extinct in a Time of 'Climate Chaos': "Climate change is not the only factor behind the insects' decline. They are also threatened by pesticides like neonicotinoids—which are extremely toxic to all bees—destruction of habitat by development and conversion of wildlands into agriculture, the spread of pathogens, and the release of non-native bees for commercial pollination."

If you're interested in learning more about bumble bees, check out the book, California Bees and Blooms: a Guide for Gardeners and Naturalists, the work of UC Davis and UC Berkeley scientists, including Robbin Thorp (1933-2019), distinguished emeritus professor of entomology at UC Davis, who also co-authored Bumble Bees of North America: an Identification Guide.

And if you see any bumble bees in your backyard in your yard between July 23 and Aug. 1, join the Third Annual Backyard Bumble Bee Count at https://www.inaturalist.org/projects/backyard-bumble-bee-count

As inaturalist.org says on its website: "Each bumble bee record submitted during the Backyard Bumble Bee Count helps researchers learn more about how bumble bees are doing and how to protect them and the environment we share. All observations collected July 23- August 1 will be included. For more information, including instructions, go to: https://backyardbbcount.wixsite.com/bumblebeecount."

A honey bee and yellow-faced bumble bee, Bombus vosnesenskii, sharing a purple coneflower in the UC Davis Department of Entomology and Nematology's Honey Bee Haven on July 14, 2010. (Photo by Kathy Keatley Garvey)

What does science tell us about this?

In a recently published EurekAlert news story, titled "Research Reveals Why Plant Diversity Is So Important for Bee Diversity," researchers at the Laboratory of Apiculture and Social Insects at the University of Sussex, related that bumble bees have distinct advantages of honey bees.

"In the study, published in the journal Ecology, the researchers used stopwatches to determine how many flowers a bee visited in one minute," according to the news release. "Using a portable electronic balance to weigh each bee, researchers found that, on average, bumble bees are almost twice as heavy as the honey bees. This means that they use almost twice as much energy as honey bees. The stopwatch results showed that they visit flowers at twice the rate of honey bees, which compensate in terms of energy efficiency."

Bumble bees dominated on such species as lavender and "were visiting flowers at almost three times the rate of honey bees."

 "While they forage on the same flowers, frequently we find that bumble bees will outnumber honey bees on a particular flower species, while the reverse will be true on other species growing nearby," said Professor Francis Ratnieks. "What was remarkable was that differences in foraging energy efficiency explained almost fully why bumble bees predominated on some flower species and honey bees on others."

The professor said that in essence, "bumble bees have an advantage over honey bees in being faster at visiting flowers, so can gather more nectar (energy), but a disadvantage in being larger, and so using more of the nectar energy to power their foraging. On some flower species this gave an overall advantage to bumble bees, but on others to honey bees."

(The late Robbin Thorp (1933-2019), distinguished emeritus professor at UC Davis and a global bumble bee expert, told us that bumble bees are earlier risers than honey bees and can forage at lower temperatures. He co-authored Bumble Bees of North America: An Identification Guide (Princeton University Press) and California Bees and Blooms: A Guide for Gardeners and Naturalists (Heyday Press). 

The Sussex researchers studied 22 flower species in southern England and analyzed the behavior of more than 1000 bees. They found that "energy efficiency" is a key factor when it comes ot mediating competition.

"Bee body weight and the rate at which a bee visits flowers determine how energy efficient they are when foraging," according to the news article. "Body weight determines the energy used while flying and walking between flowers, with a bee that is twice as heavy using twice as much energy. The rate at which a bee visits flowers, the number of flowers per minute, determines how much nectar, and therefore energy, it collects. Together, the ratio of these factors determines bee foraging energy efficiency. On some flower species such as lavender, bumble bees dominated and were visiting flowers at almost three times the rate of honeybees."

The researchers said that energy (provided by nectar for bees) is a fundamental need, but the fact that honey bees and bumble bees do not compete head on for nectar is reassuring in terms of conservation and co-existence.

As Ratnieks explained: "Bumble bees have a foraging advantage on some plants, and predominate on them, while honey bees have an advantage on others and predominate on these. Bee conservation therefore benefits from flower diversity, so that should certainly be a focus on bee conservation efforts. But fortunately, flowering plants are diverse."

The abstract in Ecology:

"Revitalizing our understanding of species distributions and assembly in community ecology requires greater use of functional (physiological) approaches based on quantifiable factors such as energetics. Here, we explore niche partitioning between bumble and honey bees by comparing a measure of within‐patch foraging efficiency, the ratio of flower visitation rate (proportional to energy gain) to body mass (energy cost). This explained a remarkable 74% of the variation in the proportions of bumble to honey bees across 22 plant species and was confirmed using detailed energy calculations. Bumble bees visited flowers at a greater rate (realizing greater energy benefits) than honey bees, but were heavier (incurring greater energy costs) and predominated only on plant species where their benefit : cost ratio was higher than for honey bees. Importantly, the competition between honey bees and bumble bees had no consistent winner, thus highlighting the importance of plant diversity to the coexistence of competing bees. By contrast, tongue : corolla‐tube‐length ratio explained only 7% of the variation (non‐significant). Our results confirm the importance of energetics in understanding community ecology and bee foraging niche and highlight the energetic tightrope navigated by foraging bees, since approximately half the nectar energy gained was expended in its collection."

Have you ever seen a bumble bee sleeping?

If you slip out to your garden at night or early morning, you might find the male bumble bees asleep in, on or around the flowers.

The yellow-faced bumble bee, Bombus vosnesenskii, frequents our pollinator garden in Vacaville, Calif. By day, the bumble bees nectar on African blue basil, Mexican sunflower, lavender, salvia, foxgloves, catmint, honeysuckle, milkweed, California golden poppies and the like. Then at night, when the females return to their nests, the males find a cozy place to sleep.

They may cushion their heads on a Mexican sunflower (Tithonia) or straddle a lavender (Lavendula), holding on with their legs or mandibles.

Oftentimes they'll sleep safely and securely inside a flower that closes at night, such as a California poppy or a torch cactus. 

Our Bombus residents seem to prefer the Mexican sunflowers and lavender.

Nighty-night. Sleep tight. Don't let the praying mantids and spiders bite.  

Bee Books
Interested in bumble bees? Be sure to read the landmark  book, California Bees and Blooms: A Guide for Gardeners and Naturalists (Heyday Press). the work of UC-affiliated authors Gordon Frankie, (the late) Robbin Thorp, Rollin E. Coville, and Barbara Ertte. 

Thorp (1933-2019), a distinguished emeritus professor with the UC Davis Department of Entomology and Nematology, also co-authored Bumble Bees of North America: An Identification Guide (Princeton University Press).