The news is disturbing but not unexpected.
Scientists are linking global climate change to one reason why the worldwide population of bumble bees is declining.
An article published Sept. 28 in the journal Ecology Letters by Florida State University (FSU) researchers showed that bumble bees just aren't getting enough floral resources.
For the study, lead researcher and postdoctoral fellow Jane Ogilivie and six colleagues examined three subalpine bumble bee species in Colorado's Rocky Mountains, and found that the changing climate means fewer flowers.
"Knowing whether climate variation most affects bumble bees directly or indirectly will allow us to better predict how bumble bee populations will cope with continued climate change," Ogilivie told the FSU News Service in a press release. "We found that the abundances of all three bumble bee species were mostly affected by indirect effects of climate on flower distribution through a season."
The FSU News Service aptly headlined the research a "Stinging Report."
"When researchers think about flower effects on bees, they typically consider floral abundance to be the most important factor, but we found that the distribution of flowers throughout a season was most important for bumble bees,” Ogilivie said. “The more days with good flower availability, the more bees can forage and colonies can grow, and the bigger their populations become. We now have longer flowering seasons because of earlier snowmelt, but floral abundance has not changed overall. This means we have more days in a season with poor flower availability.”
The researchers wrote in their abstract: "Climate change can influence consumer populations both directly, by affecting survival and reproduction, and indirectly, by altering resources. However, little is known about the relative importance of direct and indirect effects, particularly for species important to ecosystem functioning, like pollinators. We used structural equation modelling to test the importance of direct and indirect (via floral resources) climate effects on the interannual abundance of three subalpine bumble bee species. In addition, we used long-term data to examine how climate and floral resources have changed over time. Over 8 years, bee abundances were driven primarily by the indirect effects of climate on the temporal distribution of floral resources. Over 43 years, aspects of floral phenology changed in ways that indicate species-specific effects on bees. Our study suggests that climate-driven alterations in floral resource phenology can play a critical role in governing bee population responses to global change."
Bumble bee expert Robbin Thorp, distinguished emeritus professor of entomology at the University of California, Davis, long ago sounded the alarm that bumble bees are in trouble. He is the co-author of Bumble Bees of North America: an Identification Guide (Princeton) and California Bees and Blooms: A Guide for Gardeners and Naturalists.
The last bumble bee we saw--the last of the season--was on Sept. 23 at Kate Frey's pollinator garden at the Sonoma Cornerstone, Sonoma. It was a yellow-faced queen bumble bee, Bombus vosnesenskii, nectaring on a spiked floral purple plant, Salvia ‘Indigo Spires' (Salvia farinacea x S. farinacea). The queen had apparently emerged from hibernation to find food on that warm summerlike day.
I knelt to capture some images.
"Oh, it's just a bumble bee," scoffed one tourist, casually sipping a glass of wine. "They're everywhere."
Sadly, they're not.
Think bees. Think butterflies. Think plants that will attract them.
Members (you can join online or at the gate) can peruse and purchase plants from 9 to 11 a.m., and the general public from 11 a.m. to 1 p.m. Members save 10 percent off their plant purchases, while new members receive an additional $10 off as a thank-you gift.
You can chat with the Arboretum folks to pick out that special plant you're seeking. They also provide an online list of available plants and/or you can download The Life After Lawn: Garden Gems Plant List.
Many of the plants at the sale are All-Stars. What's an All-Star? The Arboretum horticultural staff has identified "100 tough, reliable plants that have been tested in the Arboretum, are easy to grow, don't need a lot of water, have few problems with pests or diseases, and have outstanding qualities in the garden." Many are California native plants and support native birds and insects. Most All-Star plants can be successfully planted and grown throughout California.
If you miss the Oct. 7th sale, not to worry. There are two more fall plant sales:
Saturday, Oct. 21
Open to the Public: 9 a.m - 1 p.m.
Saturday, Nov. 4
Public Clearance Sale: 9 a.m. - 1 p.m.
It's a good idea to BYOB (Bring Your Own Box), BYOW (Bring Your Own Wagon) or BYOC (Bring Your Own Cart).
While you're there, check out the 100-acre Arboretum, including the nearby Ruth Risdon Storer Garden (aka Storer Garden), a Valley-wise garden,and the Carolee Shields White Flower Garden and Gazebo (aka White Garden). Have you seen all of the 17 special gardens and collections?
They're called "living museums" because that's what they are. Living museums. And especially when they attract pollinators!
If you're looking for plants to attract pollinators, including bees and butterflies, then the UC Davis Arboretum's Plant Sale on Saturday, Oct. 22 is the place to "bee."
A public fall clearance sale will be held from 9 a.m. to 1 p.m. at the Arboretum Teaching Nursery on Garrod Drive, UC Davis campus. It will feature a "wide selection of Arboretum All-Stars, California natives, and gorgeous drought-tolerant plants," officials said. Members (new members can join at the door) save 10 percent and also reap other benefits.
The sale will include more than 16,500 plants and more than 450 varieties.
Will they have milkweed? Yes.
"It looks like we'll have plenty of milkweed, two varieties--Kotolo (Asclepias eriocarpa) and showy milkweed (Asclepias speciosa)," said Katie Hetrick, director of communications.
Will they have butterfly bush (Buddleia)? Yes.
"We have a ton of Buddleia," said Hetrick, mentioning just a few: Magenta Munchkin, Dark Dynasty, Buzz, Orchid Annie, Purple Haze, Lavender Cupcake--and "The Chips": Lilac Chip, Pink Micro Chip, and Blue Chip Jr.
"And let's not forget all the Salvias!" Hetrick said. "Those are a nectar fave with pollinators including butterflies, bees and hummingbirds!" Among the Salvias on sale: Bee's Bliss, Pacific Blue, Marine Blue, Pozo Blue, Debbie's Rose, Little Kiss, Red Swing, Violet Riot, Royal Bumble, Hot Lips, and Scott's Red.
Taylor Lewis, UC Davis Arboretum and Public Garden Nursery Manager, related that pipevine, the host plant of the pipevine swallowtail butterfly (Battus philenor), will be available.
Ellen Zagory, director of horticulture, listed some of her favorite sunflower family plants that attendees can buy:
- Aster 'Monch'
- Coreopsis, 'Little Penny'
- Coreopsis, 'Enchanted Eve'
- Coreopsis, 'Red Elf'
- Echibeckia, 'Summerina Brown'
- And lots of Echinacea (cone flowers)
For a full list of the plants available, download the PDF.
And, it's interesting to see what folks in the area have planted instead of lawns. The Aboretum's web page offers great ideas.
Do you know how much acres in the United States are planted in lawn? Huffington Post reports in a 2015 news story: "According to a new study from NASA scientists in collaboration with researchers in the Mountain West, there is now an estimated total of 163,812 square kilometers, or more than 63,000 square miles, of lawn in America — about the size of Texas."
All that manicuring, all that water, all that work. And little or no food or shelter for the pollinators.
Every well-manicured lawn "uses up to 900 liters of water per person per day and reduces sequestration effectiveness by up to 35 percent by adding emissions from fertilization and the operation of mowing equipment," Huffington Post says.
Indeed, lawn is our nation's single largest "crop."
But it doesn't have to be. There IS life after lawn. And there is MORE life after lawn.
If you have a patch of salvia (sage) growing in your yard, watch for the nectar robbers.
Carpenter bees are among the insects that engage in nectar robbing. They drill a hole in the corolla of the flower, circumventing the usual plant-pollinator relationship. In other words, they're “cheating” pollination by "stealing" the nectar. Scientists call this "robbing the nectar."
The most prevalent nectar robbers in our yard are the mountain carpenter bees, Xylocopa tabaniformis orpifex. They're better at drilling holes than the Texas oilmen.
If you watch closely, you may see a honey bee following the carpenter bee around. She's taking the easy way out, finding the hole pierced by the carpenter bee and then gathering nectar to take back to her colony.
If a flower could communicate, it would probably say something like "Hey, you're doing an end run to get my nectar. Please don't use the side entrance--I have a front door."
Oh, the life of a praying mantis...
You can hang upside down like an acrobat, shading yourself from the sun while waiting for prey and avoiding predators. You can crawl beneath dense leaves, the better to ambush, snatch and eat an unsuspecting bee. And you can mate with a fine-looking specimen like yourself and produce some more fine-looking specimens.
Life doesn't get any better than this if you're a praying mantis. (Unless, of course, you're a male mantid and the female practices sexual cannibalism. Or, if you're a newly emerged offspring and your brothers and sisters are feasting on one another and then...eyeing you.)
Finding praying mantids is not so easy. Sometimes the slightest movement in the leaves will reveal their location. Sometimes when you water a plant, they'll emerge, looking quite irritated--if mantids can look irritated. Other times they're blatantly perched on top of a blossom or lurking beneath it.
Up until recently, we'd never actually seen them mating. But there they were that warm midsummer day on Sept. 17 in the Häagen-Dazs Honey Bee Haven doing just that. See, the praying mantids like to hang out in the bee garden because that's where the bees are. The half-acre garden is located next to bee research hives at the Harry H. Laidlaw Jr. Honey Bee Research Facility on Bee Biology Road, University of California, Davis.
Ah, we thought, a "lover-ly" photo to add to the educational collection of Lynn Kimsey, director of the Bohart Museum of Entomology and professor of entomology at the University of California, Davis.
So, we took a few photos, being careful not to interrupt them.
If this were a documentary being filmed about the birds 'n the bees, can't you just hear it? The Cole Porter hit, "Let's Do It," softly playing in the background:
...And that's why birds do it
Bees do it
Even educated fleas do it
Let's do it, let's fall in love.
All the while, the Cleveland or blue sage (Clevelandi salvia) stirs with life. A hummingbird, honey bees and carpenter bees drop down to investigate the blossoms and sip a little nectar. A garden spider patrols its sticky web. A scared lizard darts into the shadows.
Ants lumber by with their heavy loads. No sign of any "educated fleas," though.