- Author: Kathy Keatley Garvey
If you've ever been asked that, you may have responded--quite politely--"Small, thank you!"
You probably didn't thank the squash bees.
But as we celebrate Thanksgiving with family and friends, let's remember that squash bees probably pollinated the pumpkin that ended up as a pie on your table.
The squash bee, Peponapis pruinosa, is a specialist that pollinates only the cucurbits or squash family, Cucurbitaceae, which includes pumpkins, squash, gourds, cucumbers and zucchini. P. pruinosa is a species of solitary bee in the tribe Eucerini, the long-horned bees. There's also another genera, Xenoglossa.
Squash bees are early risers, rising before the sun does. They begin pollinating the blossoms as soon as they open. Other bee species, such as honey bees (which are non-natives), don't visit the flowers so early.
Around noon, the blossoms close for the day, so there's a limited time for pollination--and a limited time to admire and photograph them.
The females are ground nesters. "The males sleep in the blossoms at night and wait for the females to arrive," the late late Robbin Thorp (1933-2019), UC Davis distinguished emeritus professor of entomology, told us.
Another attribute: The squash bee is a native of North America, unlike the honey bee.
"Before Europeans brought honey bees to the New World, squash bees were busy aiding the adoption, domestication, spread, and production of squashes and gourds by indigenous peoples throughout the Americas," according to an article by USDA research entomologist James Cane.
"Hey, there, pumpkin, do you want another piece of pie, pollinated by our native bees, the squash bees?"
- Author: Kathy Keatley Garvey
If you're having pumpkin pie or butternut squash this Thanksgiving, thank the squash bee.
Squash bees are specialists (not generalists) that pollinate only the cucurbits or squash family, Cucurbitaceae, which includes pumpkins, squash, gourds, cucumbers and zucchini.
Last summer we saw dozens of Peponapis pruinosa pollinating our squash and cucumbers. Peponapis pruinosa is a species of solitary bee in the tribe Eucerini, the long-horned bees.
"Isn't that a honey bee?" a friend asked.
"No, it's a squash bee; it's smaller than the honey bee."
"Never heard of it."
Other factoids, as shared with us by the late Robbin Thorp, distinguished emeritus professor of entomology at UC Davis:.
- Both the males and females are golden brown with a fuzzy yellow thorax. The males have a yellow spot on their face.
- Males sleep in the blossoms at night. There they wait for the females to arrive.
- Squash bees are early risers (they rise before the sun does). They begin pollinating the blossoms as soon as they open in the morning. Other bee species, such as honey bees, don't visit the flowers so early. The squash blossoms close after several hours so there's a limited amount of pollination time.
If you're aiming to photograph them, get there early. If you don't, you will find the blossoms closing.
- Author: Kathy Keatley Garvey
In case you missed it, today was National Pumpkin Day.
But it ought to be National Squash Bee Day, because the squash bee (my favorite species is Peponapis pruinosa) is an important pollinator of squash and pumpkins.
A little bit about the squash bees:
- Squash bees are specialists; not generalists. Squash bees pollinate only the cucurbits or squash family, Cucurbitaceae, which includes pumpkins, squash, gourds, cucumbers and zucchini.
- Both the males and females are golden brown with a fuzzy yellow thorax. The males have a yellow spot on their face.
- Males sleep in the blossoms at night. They're waiting for the females to arrive.
- Squash bees are early risers (they rise before the sun does). They begin pollinating the blossoms as soon as they open in the morning. Other bee species, such as honey bees, don't visit the flowers so early. The squash blossoms close after several hours so there's a limited amount of pollination time.
Wikipedia says: "The name squash bee, also squash and gourd bee, is applied to two related genera of bees in the tribe Eucerini; Peponapis and Xenoglossa." Both genera are oligoleges (pollen specialists) on the cucurbits.
Another reason why we should be concerned, according to Wikipedia: "Species such as Peponapis pruinosa have been in decline due to several reasons, probably at least in part to pesticide sensitivity."
Happy Squash Bee Day!
- Author: Kathy Keatley Garvey
But among the people who study pollinators, it is.
Also known as a squash bee, it is an important pollinator of cultivated crops of squash, pumpkins, and others members of the genus Cucurbita.
Enter Katharina Ullmann, a graduate student in the Neal Williams lab in the Department of Entomology and Nematology at the University of California, Davis.
She researches them, studying their persistence in agricultural landscapes.
And on Wednesday, June 4, Ullmann will present a seminar on her research: "Squash Bee Persistence in Agricultural Landscapes: the Role of Connectivity and Disturbance" from 12:10 to 1 p.m. in 122 Briggs Hall, located off Kleiber Hall Drive. This is the last in the series of spring seminars hosted by the department.
"It is well documented that wild native bees can benefit many crops through increased seed and fruit set, thus providing sustainable pollination alternatives in cases of honey bee decline and increased honey bee rental prices," Ullmann says. "Yet, it is unclear how to best manage crop systems to support wild native bees. Research on enhancing wild native bees has historically focused on field border management. However, to ensure the sustainability of a crop-pollination system, a comprehensive approach should also include within field practices."
"Promoting a whole-farm pollinator management strategy is especially important given that agricultural intensification is associated with practices that negatively impact wild native bees. Whole-farm strategies may provide effective alternatives for growers who are slow to adopt resource-intensive, border-management practices. The proposed project will contribute to our understanding of these strategies by determining the impact of tillage practices and crop rotations on a ground-nesting, native bee that is an important pollinator in a specialty crop system."
Ullmann said that Cucurbita crops (including squash and pumpkin) rely on pollinators to set fruit. "The specialist squash bee, Peponapis pruinosa, is an important pollinator of Cucurbita and can reduce grower reliance on rented honey bee colonies. In-field management is particularly relevant for this species given that it nests preferentially below its host's vines. I will use observational surveys and manipulative experiments to identify crop rotation schemes and tillage practices that benefit P. pruinosa. These results provide insights into how species persist in agricultural landscapes, with an emphasis on the roles of connectivity and disturbance."
Ullmann, who expects to receive her doctorate in entomology in September 2014, researches population persistence in dynamic landscapes, and on-farm beneficial insect habitat enhancements. Her interests also include supporting citizen science, translating research related to pollinator conservation and encouraging dialogue between researchers and farmers.
She developed a native bee YouTube channel aimed at providing a direct line of communication between university researchers, farmers and the general public. In addition, she developed the blog Pollinator Farm and associated social media handles on Twitter and Facebook.
Ullmann's seminar on June 4 is to be video-recorded for later posting on UCTV.
- Author: Kathy Keatley Garvey
Rachael Long, Yolo County farm advisor and director of the Yolo County Cooperative Extension program, has lined up a group of outstanding speakers at her Pollination Workshop on Friday, Oct. 11.
Open to the public (no registration required), the event will take place from 8:30 to noon in Norton Hall, 70 Cottonwood St., Woodland.
You'll hear how hedgerows enhance biodiversity and provide crop benefits in agricultural landscapes, how insecticides reduce honey bee visitation and pollen germination in hybrid onion seed production, and why multiple stresses are hard on honey bees. Assisting her in coordinating the workshop is Katharina Ullmann, graduate student in the Neal Williams lab, UC Davis Department of Entomology and Nematology.
Those are just a few of the topics.
The agenda:
8:30 to 8:35
Introductions and Updates
Rachael Long, Farm Advisor/County Director, UCCE Yolo County
8:35 to 8:55
"Hedgerows Enhance Biodiversity and Provide Crop Benefits in Agricultural Landscapes"
Rachael Long
8:55 to 9:20
"Sustainable Pollination Strategies for Specialty Crops"
Neal Williams, associate professor, UC Davis Department of Entomology and Nematology
9:20 to 9:40
"Insecticides Reduce Honeybee Visitation and Pollen Germination in Hybrid Onion Seed Production"
Sandra Gillespie, postdoctoral researcher in Neal Williams lab, UC Davis Department of Entomology and Nematology
9:45 to 10:10
"Best Management Practices for Squash and Pumpkin Pollination"
Katharina Ullmann, graduate student in Neal Williams lab, UC Davis Department of Entomology and Nematology
10:10 to 10:20
Break
10:20 to 10:45
"Native Bee Nesting in Agricultural Landscapes: Implications for Sunflower Pollination"
Hillary Sardinas, graduate student, UC Berkeley's Environmental Sciences and Policy Management
10:45 to 11:10
"Restoring Pollinator Communities and Services in California Central Valley"
Claire Kremen, professor, UC Berkeley's Environmental Sciences and Policy Management.
11:10 to 11:35
"Maintaining Honey Bee Hives for Hive Health"
Billy Synk, manager and staff research associate, Harry H. Laidlaw Jr. Honey Bee Research Facility, UC Davis
11:35 to Noon
"Multiple Stresses are Hard on Honey Bees"
Extension apiculturist Eric Mussen, UC Davis Department of Entomology and Nematology
For more information, contact Rachael Long at (530) 666-8734 or rflong@ucdavis.edu.
Note that one of the speakers, Sandra Gillespie, will be presenting a UC Davis Department of Entomology and Nematology seminar next Wednesday, Oct. 16 on “Parasites and Pesticides: Indirect Effects on Pollination Service.” It will take place from 12:10 to 1 p.m. in 122 Briggs Hall. It will be videotaped for later viewing on UCTV.
