- Author: Kathy Keatley Garvey
Have you read the excessive heat warnings and the guidelines to prevent heat illnesses as triple-digit temperatures hold us hostage in Yolo and Solano counties and elsewhere?.
UC Davis Safety Services related this week:
- Know the signs and symptoms of heat exhaustion and heat stroke.
- Keep potable water on hand at all times for consumption. It is recommended to ingest approximately four 8-ounce cups of fresh water per hour
- Cool off in well shaded or air-conditioned areas.
- Wear lightweight, loose-fitting and light-colored clothing.
- If possible, stay indoors and avoid strenuous work during the hottest part of the day.
- Minimize direct exposure to the sun whenever possible and wear sunscreen to prevent sunburn.
- Never leave children, disabled adults, or pets in parked vehicles.
- Listen to local weather forecasts and stay aware of upcoming temperature changes.
But what about the feral honey bee colonies?
All honey bee colonies must maintain a temperature of 94 degrees, or the brood (eggs, larvae and pupae), will be adversely impacted, as the late Extension apiculturist Eric Mussen (1944-2022) of the UC Davis Department of Entomology and Nematology used to say. When the inside temperature rises above 94 Fahrenheit, bees resort to (1) bringing more water into the colony to cool it down and (2) bee bearding, meaning that some of the adults will leave the colony and "beard" just outside the entrance to help reduce the heat load inside. The "bearders" are helping their brothers and sisters-to-be survive.
That said, it was interesting this week to see the bee-bearding phenomenon on a feral honey bee colony in a sycamore tree on the UC Davis campus. Most people and bicyclists wouldn't notice it, unless they're inclined to look up 30 feet.
Bees know what they're doing,. and they've been bearding for millions of years. So, no poking, no prodding, no choking them with smoke, no dousing them with water. Or worse, what if a passerby panics and calls an exterminator?
Just leave 'em alone. The bees know what they're doing.
They're engaging in thermoregulation. When the temperature drops below 94, they'll cluster and shiver their wing muscles to keep the colony warm. If the temperature rises above the required temperature, the worker bees will gather more water and deposit the droplets inside the hive so other bees can fan and cool the colony. Bearding is part of the process.
As Mussen told us: "Like most other animals, the bodies of honey bees are mostly water. Thus, they need to drink water routinely as we do. Additionally, water (or sometimes nectar) is critical for diluting the gelatinous food secreted from the head glands of nurse bees, so that the queen, developing larvae, drones, and worker bees can swallow the food. They use water to keep the brood nest area at the proper relative humidity, especially when it gets hot and dry outside the hive. Water droplets, placed within the brood nest area, are evaporated by fanning worker bees and that cools (air conditions) the brood nest area to keep the eggs and developing brood at the critical 94 degrees Fahrenheit required for proper development."
"On extremely dry, hot days, all bee foraging except for water will cease," Mussen noted. "Under those conditions it has been estimated that the bees may be bringing back nearly a gallon of water a day."
We could learn a thing or two from the bees.
(See the bee activity on this UC Davis campus 'bee tree' on a YouTube video)
- Author: Kathy Keatley Garvey
Today, during the 62nd annual international conference of the Society of Nematologists, being held July 9-14 in Columbus, Ohio, The Proceedings of the National Academy of Sciences (PNAS) published a UC Davis research team's important--and exciting--research paper on root-knot nematodes.
It's online at “Root-Knot Nematodes Produce Functional Mimics of Tyrosine-Sulfated Plant Peptides."
Basically, the researchers discovered that “both a harmful plant bacterium and a parasitic worm can mimic a plant peptide hormone to enhance their ability to infect plants.”
It's a joint project of nematologist Shahid Siddique, an associate professor in the Davis Department of Entomology and Nematology, and Siddique and UC Davis distinguished professor Pamela Ronald, a plant pathologist and geneticist in the Department of Plant Pathology and the Genome Center. They are the corresponding authors. Joint first-authors are Henok Zemene Yemer, formerly of the Siddique lab and now with Gingko Bioworks, Emeryville, and Dee Dee Lu of the Ronald lab.
It's like hijacking plant development to facilitate parasitism, according to Siddique. “This finding showcases an amazing case of convergent evolution across three different types of organisms, revealing how diverse life forms can develop similar strategies for survival.”
“Root-knot nematodes are a major threat to various crops, including fruit trees and vegetables,” Siddique said. “In California, tomatoes, almonds, and walnuts are among the major hosts susceptible to root-knot nematode infection.”
Siddique and UC Davis distinguished professor Pamela Ronald, a plant pathologist and geneticist in the Department of Plant Pathology and the Genome Center, are the joint corresponding authors. Joint first-authors are Henok Zemene Yemer, formerly of the Siddique lab and now with Gingko Bioworks, Emeryville, and Dee Dee Lu of the Ronald lab.
Plant-parasitic nematodes (PPNs) are among the most destructive plant pathogens, causing an annual economic loss of $8 billion to U.S. growers and more than $100 billion worldwide, the authors said.
The team also included emerita professor Valerie Williamson of the former Department of Nematology; Maria Florencia Ercoli, postdoctoral fellow in the Ronald lab; Alison Coomer Blundell, a doctoral candidate in the Siddique lab; and Paulo Vieira of the USDA's Mycology and Nematology Genetic Diversity and Biology Laboratory, Beltsville, Md.
“Plant peptides containing sulfated tyrosine (PSY)-family peptides are peptide hormones that promote root growth via cell expansion and proliferation,” the authors explained. “A PSY-like peptide produced by a bacterial pathogen has been shown to contribute to bacterial virulence. Here, we discovered that PSY-like peptides are encoded by a group of plant-parasitic nematodes known as root-knot nematodes. These nematode-encoded PSY mimics facilitate the establishment of parasitism in the host plant. Our findings are an example of a functional plant peptide mimic encoded by a phytopathogenic bacterium (prokaryote) and a plant-parasitic nematode (an animal).”
The project drew financial support from a collaborative grant awarded to Siddique and Ronald from the National Science Foundation's Division of Integrative Organismal Systems.
Siddique, a member of the UC Davis faculty since 2019, focuses his research on basic as well as applied aspects of interaction between parasitic nematodes and their host plants. “The long-term object of our research is not only to enhance our understanding of molecular aspects of plant–nematode interaction but also to use this knowledge to provide new resources for reducing the impact of nematodes on crop plants in California.”
Ronald, noted for her innovative work in crop genetics, especially rice, is recognized for her research in infectious disease biology and environmental stress tolerance. Thomson Reuters named her one of the world's most influential scientific minds and Scientfic American recognized her as among the world's 100 most influential people in biotechnology. In 2022 Ronald received the Wolf Prize in Agriculture.
The next steps? “Currently, we are working to understand the mechanism by which these peptides contribute to the nematode infection,” Siddique said. “This entails the characterization of receptors involved and gaining insights into transcriptional changes.”
- Author: Kathy Keatley Garvey
It's a butterfly that breeds on thistles, such as Cirsium, Carduus and Silybum.
The one that visited our yard June 17 wasn't visiting a thistle, however. It landed on a cactus.
It's an orange and black butterfly (orange wings with black markings). White fringes the edges.
UC Davis distinguished professor Art Shapiro, who has monitored butterfly populations in Central California since 1972 and maintains a website, Art's Butterfly World, says it's an abundant, weedy species on his transect."
The Mylitta Crescent is featured on his website banner.
"The Mylitta Crescent breeds on Thistles," Shapiro writes. "It originally used native species of Cirsium, probably mostly in wet habitats. With the naturalization of weedy European species of Cirsium, Carduus and Silybum, it is now found in all kinds of disturbed (including urban) habitats. Many of the weedy hosts dry up by early summer and it then must contract down to colonies of Bull Thistle, Cirsium vulgare, which persists all summer (or, on the East slope, Canada Thistle, C. arvense). The part-grown larvae overwinter and can be found sunning themselves on mild midwinter days. The upperside pattern of males varies greatly and is sometimes nearly obsolescent. The ventral hindwing is redder in cold seasons, especially in females, and the crescent marking is more strikingly silvered. Males patrol along roadsides and often sit at ground level. Both sexes visit many flowers, from Thistles to Yerba Santa to Heliotrope. Breeds continuously in warm weather: February-November near sea level, June-October in the high country, often one of the last species flying and visiting Rabbitbrush there."
This butterfly isn't as recognizable as the monarch icon, but it's still striking.
- Author: Kathy Keatley Garvey
But it's not going to happen.
So here we are in our Vacaville pollinator garden, looking at the Chinese forget-me-nots. We see honey bees, leafcutter bees, syrphid flies, lady beetles, cabbage white butterflies, and other critters foraging. It's National Pollinator Week.
And then we see a pinkish caterpillar munching away on one of the sky-blue blossoms. He's a very hungry caterpillar. Did we say "hungry?" He's ravenous. Absolutely ravenous!
It's a tobacco budworm, Heliothis virescens, as identified by UC Davis distinguished professor Art Shapiro, an expert on Lepidopterans who has monitored butterfly populations in central California since 1972--and also studies moths. (See his butterfly website.)
In its adult stage, the tobacco budworm will become a moth. (If we let it!)
In its larval stage, it can vary in color from pale green to pink to dark red to maroon, according to a University of Florida entomological fact sheet.
"Tobacco budworm is principally a field crop pest, attacking such crops as alfalfa, clover, cotton, flax, soybean, and tobacco," the University of Florida entomologists related. "However, it sometimes attacks such vegetables as cabbage, cantaloupe, lettuce, pea, pepper, pigeon pea, squash, and tomato, especially when cotton or other favored crops are abundant. Tobacco budworm is a common pest of geranium and other flower crops such as ageratum, bird of paradise, chrysanthemum, gardenia, geranium, petunia, mallow, marigold, petunia, snapdragon, strawflower, verbena, and zinnia."
Naturalist-photographer Greg Kareofelas, a Bohart Museum of Entomology associate, remembers rearing one that he plucked from his geraniums a few years ago. We are not going to rear this one. Tobacco budworms are not our buddies.
This afternoon honey bees tried to push the pest away. They did not succeed.
Tomorrow the California scrub jays nesting and chirping in the cherry laurels probably will!
- Author: Kathy Keatley Garvey
You're shaking my confidence daily...
--"Oh, Cecelia" written by Paul Simon of Simon and Garfunkle
If you think of the song, "Oh, Cecelia,' every time you pronounce Phacelia (the plant), you're not alone.
Pollinators, especially honey bees, bumble bees and syrphid flies, love the lacy Phacelia (Phacelia tanacetifolia) at the Joseph and Emma Lin Biological Orchard and Garden (BOG) near the Botanical Conservatory at the University of California, Davis.
P. tanacetifolia, a leggy three-foot plant clustered with light blue to purple flowers, is a member of the borage family, Boraginaceae. It's native to the southwestern United States and northern Mexico.
Where is the BOG? Back of Parking Lot 26 on Kleiber Drive.
What's in it? It's landscaped with several dozen species of heritage fruit trees and colorful mini-gardens.
A sign describes the garden. "This unique landscape showcases a slice of biodiversity in the heart of the central campus and is a hub for outdoor learning...The drought-tolerant plants growing in these beds are all from Mediterranean regions with similar summer-dry climates in Davis, including the Mediterranean, South Africa, Chile and Australia. The beds demonstrate the diversity of plants that can grow in the Sacramento Valley and provide students and campus visitors with a variety of species to observe and study."
So, basically, BOG is an outdoor laboratory for hands-on learning. "Classes perform biodiversity assessments, record insect observations and monitor the onsite weather stations," Instagram relates. Student employees, interns and volunteers at the Botanical Conservatory take care of the garden.
Among the flowers blooming in the BOG in the early spring, by color:
- Red: European red flax, Linum grandiflorum rubrum, an annual that's native to Algeria
- Yellow: tidy tips, Layia platyglossa, an annual that's native to California
--The seep monkey flower, Mimulus guttatus, native to California
--Lupine, Lupinus, native to North America. - Blue: Desert bell, Phacelia campanularia, an annual herb that is native to California and endemic (limited) to California.
- Lavender: Phacelia, also called Lacy phacelia, blue tansy or purple tansy (Phacelia tanacetifolia), native to the southwestern United States
--Lupine: Lupinus, native to North America - Red-Orange-Yellow: Blanket flower or Gaillardia (Gaillardia × grandiflora), native to North and South America
- Orange: California golden poppies, Eschscholtzia californica
But it's the Phacelia that's the big draw today.
Phacelia, you're breaking my heart...