- Author: Kathy Keatley Garvey
Especially when it comes to bumble bee colonies.
Postdoctoral scholar Rosemary Malfi of the Neal Williams lab, University of California, Davis, will speak on “Timing Is Everything: Bumble Bee Colony Performance in Response to Seasonal Variation in Resources” at 4:10 p.m., Wednesday, May 30 in 122 Briggs Hall.
“Wild bee populations are considered to be strongly regulated by the availability of flowering resources on which they rely for food, that is, pollen and nectar, yet we lack robust, experimental data demonstrating the mechanistic connections between the floral resource environment and bee population health," Malfi says. "The temporal distribution of resources, in particular, is an understudied but potentially highly influential aspect of habitat quality affecting bees. Bumble bees (Bombus spp.) are annual, euosocial insect with high conservation value. Because their colonies must grow for several weeks before reproducing the timing of within-season resource abundance and scarcity is especially likely to impact their demographic performance."
At her seminar, Malfi will describe her postdoctoral work here at UC Davis, "in which we investigated the importance of the timing of floral resource abundance for bumble bee (Bombus vosnesenkii) colony success through two large field experiments involving the manipulation of the food environment that colonies experienced. In the first study, we assessed how differences in the resource environment early in colony development affected both individual and colony level traits across the season using radio-frequency technology (RFID) and mark recapture methods. In the second study, we determine whether a pulse of food resources early in development, compared to a pulse delivered later during the 'pre-reproductive' phase, has a greater or similar impact on the peak size and reproduction of bumble bee colonies. We use a null method of exponential colony growth to explore whether resource pulses have persistent effects on colony growth after the pule itself has disappeared. Together these studies demonstrate that resource abundance early in development is critical for the success of bumble bee colonies, and this populations."
A native of Philadelphia, Rosemary received her bachelor of arts degree from Bryn Mawr College, an all-women's liberal arts school in the greater metro area, and worked two years at the Academy of Natural Sciences of Philadelphia as a lab manager for the in-house Patrick Center for Environmental Research.
Mali holds a doctorate in environmental science (ecology) from the University of Virginia in 2015 , studying with major professor T'ai Roulston. She focused her doctoral research on the influence that flower (i.e. food) availability and parasitism have on bumble bee (Bombus spp.) population dynamics, and how risks associated with these factors vary among species within a community. In her work, integrating field observations, parasite analysis, colony manipulations, the use of radio frequency technology, and simulation modeling, she investigated these sources of environmental influence independently and interactively through studies that focus on bumble bee populations and environmental risks present in northern Virginia.
Among the bumble bee parasites Malfi has studied: Nosema bombi, a pathogenic fungus implicated in "the precipitous and rapid decline of several bumble bee species across North America." During her graduate studies, she became especially interested in the interaction between bumble bees and one of their parasitoids, the conopid fly. "Although the basic biology of this interaction has been described," she says, "little is currently known about the ecology of this host-parasitoid relationship, particularly in North America." Malfi discussed her work on the conopid fly at the January 2016 open house of the Bohart Museum of Entomology, UC Davis.
Malfi's postdoctoral position at UC Davis ends in September, and then she will be moving to Massachusetts with her family. She will be working in the lab of Lynn Adler at the University of Massachusetts, Amherst, to carry out research on the influence of diet on bumble bee colony development and health.
Career plans? "For now, my career plans are to continue pursuing research on wild bee population health," she says. "In my next position at UMass Amherst, I'll be focusing on how the diet of bumble bees may mediate the influence of pathogenic parasites on individual- and colony-level performance."
- Author: Kathy Keatley Garvey
The black-tailed bumble bee wasn't flying very well.
You wouldn't, either, if you were trying to fly with a backpack on your back.
Except this wasn't a backpack but sticky pollen.
The bumble bee, Bombus melanopygus, was foraging in our Spanish lavender last weekend when we noticed something unusual: a sort of hump on the back, a reddish coloration.
"That mass on the rear of the Bombus melanopygus thorax is a load of pollen," said Robbin Thorp, distinguished emeritus professor of entomology at the University of California, Davis. "A larger lump than most that I have seen before. Deposited from several visits to some 'nototribic' flower. Nototribic flowers are those that deposit pollen on the upper side of visitors. Like salvias with their anthers at the top of the tube."
Biologist Africa Gomez of the UK writes about it in her abugblog: "Some bees...specialize on collecting pollen from flowers with raised anthers, which touch over the bee's head or thorax when bees land on them. These are called nototribic flowers and include species from the Lamiaceae (the mint family) and Scrophulariaceae (the figwort family)."
"Although bee-pollinated plants benefit from bees taking nectar--exchanging nectar for inadvertent pollination- they do not benefit when potential pollinators efficiently gather the pollen for their offspring consumptions instead," Gomez points out in her blog. "Nototribic plants in response to specialised pollen gathering by bees, have flowers that make pollen hard to collect, even when they have plentiful nectar. Only bees equipped with either specialised behaviour or morphological modifications, or both can effectively make use of their pollen."
As for the bumble bee foraging on our Spanish lavender, it eventually bumbled off with that heavy load, taking flight like a weighted Spruce Goose.
- Author: Kathy Keatley Garvey
Might As Well Be Spring
"I'm as restless as a willow in a windstorm
I'm as jumpy as puppet on a string
I'd say that I had spring fever
But I know it isn't spring."--Frank Sinatra
Wait, it is spring!
Today is the day we've all be waiting for--the first day of spring.
If you're lucky, you'll see bumble bees nectaring on spring flowers, including nectarine blossoms.
We spotted this bumble bee, Bombus melanopygus, also known as a black-tailed bumble bee, heading toward our nectarine tree and foraging on the blossoms.
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 little buddy, Bombus melanopygus, appears to be nesting nearby due to her frequent visits to the nectarine blossoms. Hmm, wonder if she is occupying a rodent hole or maybe an old birdhouse....
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, distinguished emeritus professor of entomology at UC Davis, who is also the co-author of Bumble Bees of North America: an Identification Guide.
Happy spring!
- Author: Kathy Keatley Garvey
It's Thanksgiving Day and time to give thanks for NOT what we WANT, but what we HAVE.
And, not for what we OWN, but what we CANNOT.
That includes the yellow-faced bumble bee, Bombus vosnesenskii.
On the morning of Nov. 12, we traveled to the Sonoma Cornerstone, Sonoma, to check the plants and pollinators in Kate Frey's amazing pollinator garden. Kate Frey, co-author of The Bee-Friendly Garden" (with UC San Francisco professor Gretchen LeBuhn), is a world-class garden designer and pollinator advocate.
Flashback to Sept. 23, the last time we visited the Frey garden. We noticed monarch butterflies, painted ladies, honey bees and--one bumble bee, a hungry queen Bombus vosnesenskii, newly emerged from winter hibernation to grab something to eat. Sometimes on warm sunny days, the queens will disrupt their hibernation to search for nectar. They. Are. Hungry.
At 12:30 on Nov. 12, the temperature rose to 62 degrees.
And then we saw her, The Queen. The Queen. Resplendent in gold and black, she buzzed loudly toward the spiked floral purple plant, Salvia indigo spires (Salvia farinacea x S. farinacea). Honey bees quickly moved out of her way as she claimed the nectar, all of it. Her wings glowed in the sunlight and her buzz seemed loud enough to break the sound barrier.
Is there anything more bee-utiful?
One bumble bee. One queen. A royal moment.
- Author: Kathy Keatley Garvey
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.