Let's hear it for the sweat bee.
It's one of the many tiny bees that ought to be honored and recognized during Pollination Week, June 21-27, but it's often overlooked.
We've been seeing many of this species, Halictus tripartitus, in our pollinator garden in Vacaville. It's also called the "Tripartite Sweat Bee."
Thomas "Tom" Zavortink, a research entomologist and associate at the Bohart Museum of Entomology, UC Davis Department of Entomology and Nematology, noted why this one is Halictus tripartitus. "The abdominal terga appear to have apical hair bands, suggesting Halictus, and the scutum appears to have a slight metallic coloration, which along with the small size suggests Halictus tripartitus." Zavortink focuses on the systematics and biology associated with mosquitoes and solitary bees.
Most Halictus are generalist foragers, according to the Great Sunflower Project. "They use all sorts of genera of plants from the Asteraceae to Scrophulariaceae. They are very common on composites (daisy-like disc and ray flowers) in summer and fall."
We've seen them on everything from mustard to milkweeds to catmint to rock purslane, from spring to fall. They also appear regularly on the tower of jewels (Echium wildpretii).
Let's hear it for the sweat bee, an overlooked and underloved little pollinator.
Dear Crab Spider,
Please don't eat the pollinators. You may help yourself to a mosquito, a crane fly, a lygus bug, an aphid, and a katydid, not necessarily in that order. And more than one if you like. In fact, how about an all-you-can-eat buffet of luscious lygus bugs? So good! Yes, you may tell all your arachnid friends about the nutritious, high-protein meals available just for the taking. Please do. Just don't eat the pollinators.
Crab spiders do not listen. They will eat what they want and when they want it. And they will gorge themselves. They are not interested in joining Weight Watchers. They are Wait Watchers.
For the past several months, crab spiders have been lurking on our blanket flower (Gaillardia). Most of the time, they just sit there, waiting patiently for dinner to arrive. Sometimes it's a long wait--longer than it takes for a waiter to return to your table during a rush-hour holiday lunch.
So, Ms. or Mr. Crab Spider--not sure of the gender, but "Predator" will do--dined recently on a sweat bee, a female Halictus tripartitus. We watched Predator lunge at a honey bee (missed!) and pursue at a male long-horned bee, probably Melissodes agilis.
Our cunning little arachnid no doubt nailed a few others--the "waistline" is a dead giveaway.
Today's the Fourth of July and folks are splashing in their pools.
So, what happens when a bee falls in?
Sometimes they get lucky--if there's a human around to rescue them. And sometimes their luck extends to a floating leaf.
This tiny female sweat bee, genus Halictus (probably H. tripartitus, as identified by native polinator specialist Robbin Thorp, emeritus professor of entomology at the University of California, Davis, fell into our pool and then managed to save herself by climbing onto a cherry laurel leaf.
If you look closely, you'll see another sweat bee, an even smaller one, trying to climb onboard, too.
The scenario ended well. The bee coasting along the leaf dried her wings and then flew off.
Luck be a lady...
If you like to take photos of insects that are as small as a grain of rice, then you'll love--absolutely love--stalking a sweat bee.
Sweat bees, members of the worldwide family Halictinae and order Hymenoptera, are so-named because they are attracted to human perspiration or "sweat." They probably lap up perspiration because of the salt content, according to Christopher O'Toole and Anthony Raw, authors of Bees of the World.
The most important of the many genera, the authors say, are Halictus and Lasioglossum, which are common to both the Old World and New World.
Speaking of common, Halictus is also common in bee friendly gardens and swimming pools. Ever gone for a swim and feel a tiny insect sting you? It may have been a sweat bee. ("Their sting is only rated a 1.0 on the Schmidt Sting Pain Index, making it almost painless," according to Wikipedia.)
O'Toole and Raw point out that some sweat bees are only 4mm long, which is why they can be easily overlooked and so difficult to identify.
What's unique are about these ground-nesting bees? The females of all species of sweat bees mate before winter. "This means that, unlike female solitary bees of other families, those of halictids do not have to mate before founding a nest in the spring," they write.
Native pollinator specialist Robbin Thorp, emeritus professor of entomology at the University of California, Davis, identified this little pollen-packing sweat bee (below) as a female sweat bee, Halictus tripartitus.
She was nectaring a tower of jewels (Echium wildprettii) in our yard and packing a heavy load of blue pollen she'd gathered from the plant.
The tower of jewels is native to the Canary Islands. So, if you visit the Canary Islands, you can probably see--and photograph--this little sweat bee there, too.
When a sweat bee and a honey bee share the same flower, the size difference is quite distinct.
We took this photo of a honey bee on a rock purslane (Calandrinia grandiflora) blossom.
Above it stood a tiny female sweat bee (probably Halictus tripartitus, according to native pollinator specialist Robbin Thorp, emeritus professor of entomology at the University of California, Davis).
Two bees. Two sizes. One blossom. One native. One non-native. The sweat bee is a native, and the honey bee was brought over here in the 1600s by the European colonists.
Speaking of honey bees, this is the first day to participate in TwitCause. The Häagen-Dazs brand is donating $1 per Tweet (up to $500 per day) today through Nov. 11 to support honey bee research at UC Davis.
Häagen-Dazs joined forces with ExperienceProject.com (EP), a San Francisco-based online community for sharing life experiences.
Like to support honey bee research at UC Davis? Go to www.twitcause.com. Directions on top of the page detail how to follow, retweet, and help the honey bee cause on Twitter.