What was that!

If you grow Mexican sunflowers (Tithonia) in your pollinator garden, you've probably noticed the fast-flying longhorned male bees being totally territorial.

Their job is to target whatever's on the Tithonia. It doesn't matter if it's a bumble bee, a honey bee, or a butterfly--it's fair game.

As the late Robbin Thorp (1933-2019), a global expert on bees and a distinguished emeritus professor of entomology at the University of California, Davis, used to say about the male longhorned bees, Melissodes agilis: "They're trying to save the flowers for their own species, per chance to mate with them."

Watching the territorial behavior is jaw-dropping, but imagine if you're a butterfly trying to sip a little nectar.

"Oh no! What was that heading straight at me?"

"Horrors! Here he comes again! Can't a pollinator get a little peace around here?"

The longhorned bee, Melissodes agilis, is just one of the more than 1600 species of bees found in California. If you want to learn more about them, be sure to read California Bees and Blooms: A Guide for Gardeners and Naturalists (Heyday, 2014), co-authored by scientists from UC Berkeley and UC Davis.

"California Bees and Blooms (co-authored by Gordon Frankie, Robbin Thorp, Barbara Ertter and Rollin Coville) holds a magnifying glass up to the twenty-two most common genera (and six species of cuckoo bees), describing each one's distinctive behaviors, social structures, flight season, preferred flowers, and enemies," according to Heyday.

That it does. And if you try to stop the action with your camera, it helps to set the shutter speed at 1/3000 to 1/4000 of a second. (The two images of the bee and painted lady butterfly captured with a Nikon D500 camera, mounted with a 70-180 mm macro zoom lens, with the aperture set at 5.6 and ISO at 800. Image of the bee and monarch taken with a Nikon D800 mounted with a 105mm lens, and with similar settings.)  

Robbin Thorp, distinguished emeritus professor of entomology at UC Davis. (Photo by Kathy Keatley Garvey)

Ah, pillow fights, popcorn, and marathon movies on TV, you ask?

No. "Boys' Night Out" is when the longhorned male bees in our pollinator garden in Vacaville engage in sleepovers on our Mexican sunflowers (Tithonia) and other blossoms.

At night, the girls sleep inside their nests, and the boys cluster on flowers.

Lately, we've been admiring a trio of boys--Melissodes (possibly M. robustior, as identified by Robbin Thorp, distinguished emeritus professor of entomology at the University of California, Davis)--bunking down on a Tithonia. Every day, around sunset, they head over to the same flower, arrange themselves in comfortable sleeping positions (hey, quit kicking me), and it's nighty-night! When the sun rises, they vacate the bedroom. Sometimes it's earlier than planned, no thanks to buzzing bumble bees, carpenter bees and honey bees foraging around them and disturbing their beauty sleep. The nerve!

Other species of male longhorned bees--including Melissodes agilis and Svastra obliqua--sleep on flowers at night as well.

"Most frequently, the boy bee overnight clusters are single-species clusters," says Thorp, co-author of California Bees and Blooms, a Guide for Gardeners and Naturalists, with UC-affiliated authors Gordon Frankie, Rollin E. Coville, and Barbara Ertter.

Thorp,  who holds a doctorate in entomology from UC Berkeley and taught entomology at UC Davis from 1964 to 1994,  continues to "bee involved" in research, writings, bee identification and public outreach. He teaches annually at The Bee Course (American Museum of Natural History), at the Southwestern Research Station, Portal, Ariz. The nine-day intensive  course is offered for conservation biologists, pollination ecologists and other biologists who want to gain greater knowledge of the systematics and biology of bees.

In a previous Bug Squad blog, Thorp responded to a reader's inquiry about "stings" from the clustering bees. "Boy bees cannot sting," he pointed out. "They lack a stinger which is a modified ovipositor in their wasp ancestors.  Occasionally a girl bee may spend the night out if she is caught by sudden drop in temperature.  Usually she will not be part of a group sleep over.  So don't attempt to handle unless you are confident you can tell boy bees from girl bees or they are too sleepy to defend themselves."

The reader also asked: "Typically how close to the girls' nest(s) do the boys' slumber? I want to try and make sure I don't touch it when planting at end of summer."

 "Boy sleeping aggregations are based on a suitable perch and not related to where females are nesting, but probably no more than 100 yards from the nearest female nest," Thorp answered.  "Females nest in the ground and have rather distinctive round holes about the diameter of a pencil or slightly smaller, sometimes with small piles of dirt around them looking like mini-volcanos.  The holes may be widely separated or clustered together depending on the species, but each female digs her own burrow."

The reader also wondered: "When watching the boys tonight, about ten of them started waking up and kicking each other. They finally settled down and started to nestle back in for the 'night'--it was only 6 p.m.--but I wasn't sure if my presence was getting them riled or they tend to act like kids sharing a bed?"

Said Thorp: "The boys usually settle in as the light dims in the evening.  Cool, and drizzly conditions may modify bed time. Each establishes his own spot, so there may be some jostling for position initially."

Longhorned bees are among the more than 1600 species of undomesticated bees that reside in California. In their book, California Bees and Blooms, the authors focus on 22 of the most common genera and the flowers they frequent. Meanwhile, check out Frankie's UC Berkeley Urban Bee Lab website to read more about native bees and the exciting research underway.

What's better than a yellow-faced bumble bee (Bombus vosnesenskii) on yellow mustard?

Not much. Both are signs of early spring.

Mustard is popping up all over, along with oxalyis and wild radish. The earth is warming. Spring is here. Get ready.

In the University of California book, California Bees and Blooms:  Guide for Gardeners and Naturalists, the authors write that B. vosnesenskii and B. melanopygus "are considered spring bees because that is when their population is highest, tailing off in numbers the rest of the year."

The book is the work of Gordon Frankie, UC Berkeley entomology professor; Robbin Thorp, distinguished emeritus professor of entomology at UC Davis;  photographer and entomologist Rollin Coville (he received his doctorate from UC Berkeley), and botanist Barbara Ertter, also affiliated with UC Berkeley.

Be sure to check out their companion pocket guide on the UC ANR website. It's titled Common Bees in California Gardens. It will help you identify 24 of the most common bees found in urban gardens and landscapes. That's 24 out of nearly 1600 species of native bees found in the Golden State.

 Yellow-faced bumble bee, yellow mustard, Golden State....Life is good...

It's spring and it's loud in the Spanish lavender patch.

The girls--the honey bees--are buzzing furiously as they forage among the blossoms, but so are the boys, in this case the mountain carpenter bee, Xyclocopa tabaniformis orpifex. The girls are there for the pollen and nectar to take back to their colonies, and the boys are there for some flight fuel.  And to find mates.

Xyclocopa tabaniformis orpifex is one of three species of California carpenter bees: the others are Xyclocopa varipuncta (the largest one, about the size of a bumble bee), and Xyclocopa californica. All females are mostly black. The male Xyclocopa varipuncta, aka "the teddy bear bee," is a golden with green eyes. The other males often have yellow hair on their head or thorax.

The carpenter bees usually fly from March through October, according to California Bees and Blooms, A Guide for Gardeners and Naturalists, a University of California production featuring the work of Gordon Frankie Robbin Thorp, Rollin Coville, and Barbara Ertter (Thorp is a distinguished emeritus professor of entomology at UC Davis, Frankie is a professor at UC Berkeley, and Coville and Ertter are also affiliated with UC Berkeley).

A handy identification pocket guide--a companion to California Bees and Blooms--is Common Bees in California Gardens, published by the University of California Agriculture and Nature Resources. It will help you identify 24 bees and you can lean about the distribution, flight season, nesting habits, floral hosts and how each bee species transports pollen. You'll see beautiful images by noted photographer Coville, who holds a Ph.D. in entomology from UC Berkeley.

Excellent publications! The more you know about bees, the more likely you are to protect them and plant for them.

Ah, spring! It's loud in the Spanish lavender patch...