Monday, March 12, 2012

Brittle Bush Bee Heaven

 Last year a late, very strong freeze kept many Brittle Bushes in the Tucson Mountains from blooming. In March it felt as if all kinds of interesting bees had found their way into our protected backyard habitat. Of course, the distances that these small endemic bees travel are really quite small. But for whatever reason, my BugGuide entries for last March show dozens more species than I'm finding this year.

So far I saw no Colletes (left), few Anthophora (middle) even though the Penstemons are already past their prime, and the long horned Eucera (right) are still missing. While a Leaf-cutter bee in Saguaro National Park volunteered to star in a video, I hardly see any in our backyard. The cactus bee Diadasia will certainly show up once the cacti are in flower.

Lasioglossum sisymbrii (left) is here, and several Agapostemon species (middle and right), some of them very pretty and shiny green. Some Agapostemons had been invading our living room windows throughout the winter to the delight of a resident Kukulcania Spider.

In the early morning hours, Honey Bees seem to be taking advantage of their greater body mass and thermoregulated hives: they visit the Brittle Bushes when it is still rather cool. (this observation is contrary to the info in BugGuide - Maybe the remarks there refer to climate conditions different from Arizona's)

Around noon,  by far the dominant genus in our backyard is Adrena, recognizable by their furry faces (facial fovea). I'm seeing at least 2 morpho-species, a brown one and one with a partly rust-colored abdomen. The females collect pollen into tibial brushes similar to those of honey bees. They will take the pollen to their solitary ground nests. Each egg will be laid on its own ball of pollen and sealed in its own chamber. Our sandy, dry soil is just perfect for these Mining Bees.

Adrena males are smaller and more narrowly built, with the light face that is characteristic for many male bees. They spend their time hovering and zigzagging over the flowers. They rarely land to refuel with nectar. All bees that are quietly collecting attract  their attention. Although  pheromones prevent greater confusion, these eager males zoom in on anything from Agapostemon to Honey Bee. It's quite annoying if you are trying to photograph.

If they find a conspecific female they grab it, and in most cases a struggle ensues which usually makes both bees fall off the flower and out of focus. To get photos I finally just focused on an attractive female and waited for the males to show and that worked like a charm.

The abundance of Adrena females also drew another visitor with a quite different agenda. Today I found my first Nomada Bee and promptly misidentified it as a wasp. Nomadas got their name from the fact that they have no nest of their own. Instead, they are clepto-parasitic cuckoo bees, depositing their eggs into the nests of the other bees, mostly in the genus Adrena.


  1. This weekend I was fascinated by the amount of bees around the wildflowers. As I went through my pictures, I noticed a crazy assortment of bees that looked different from one another. The brittlebush really is a strong magnet for a lot of insects. I saw lots of butterflies like the Painted Lady. Thanks for sharing your bee id's. Very interesting.

  2. Love your Sonoran Desert blog Margaret. It allows me to recharge my batteries while trying to cope with cold temperate northern European climate of sweden. I'm originally from there and long to be back in the Southwest. Keep up the good work.

  3. Hi Margarethe

    Just by way of a couple of photo challenges for you. When in the states as a Landscape Supervisor, I had the privilage one day to observe a European honey bee inside a Datura (or Jimson weed) flower. The hilarious thing was that the bee was actually drunk and under the narcotic influence of the flower's nectar. It kept buzzing it's wings on & off, stumbling around to get it's footing and just generally having a rough time of it. Here's a pic of bees in a Datura flower with bees.

    I know Datura or Jimson Weed is native to your area in the waste areas, so if you are able during the Datura's flowering period, hang out and see if you could see if you could capture on an actual video this comical scene that happens in nature.


    Okay, here is your next assignment. When I lived up in the mountains above Palm Springs for 24 years, my landscape acreage was totally dedicated to natives from the southwestern USA. One of the plants that I inserted into the landscape was California Coffeeberry (Rhamnus californica). You may have a similar shrub in the buckthorns, a plant genus there in Arizona like Rhamnus crocea , which is either called Redberry Buckthorn or Hollyleafed Buckthorn. Let me show you a pic of of the flowers which for the most part are not at all showy, infact they are very dull olive green and inconspicuous.

    My point though is that although not exactly showy and desirable to the human eye, they attract every type of insect critter in the bee, wasp, fly, knat, mosquito, beetle, etc family that you can possibly imagine. They are so numerous that a single bush looks almost alive as if moving and the sound of buzzing is incredible. The various critters are literally stumbling and falling all over themselves. My point is that the shrub attracts a fair amount of beneficial preditory insects of all types. I'd love to have a pic I could display as an example of biological advantages people can insert into their landscape for plant health care.

    Thanks , Kevin

  4. Datura has not the same effect on insects as it has on humans. Many insects utilize its nectar just fine, as I have described in an earlier blog. I doubt that the plant's alkaloids are in the nectar. It would be VERY counterproductive for a plant to poison its pollinators (although species specific incompatibilities can exist.) Your observation is an anecdote that finds me very skeptical.
    I like your idea of planting insect attracting Rhamus very much and I am actually trying to get one through the ASDM gardener.
    As for your assignments: You can buy the one-time release of my photographs, the fee will depend on the file size. You also may commission images of your choice, the fee then depends on the difficulty of getting to the subject and also on the file size that you require.
    All my images are copyrighted and may not be used, copied, printed, down-loaded in any way without my written permission.

    1. Ah that's too bad. The bees I've seen have always come stumbling out of the Datura flowers as if intoxicated. They weren't or didn't appear poisoned in that sense, just a little typsy. But I seriously did observe it. In fact I brought my employer back and showed them.

      Actually, I would love to simply link to your website's photos and drive more traffic here, though I'd have no problem at a future date applying the fee. But the Rhamnus - Coffeeberry flower s attracting pollenators is a great illustrative tools for gardeners to use their thinking caps when designing a garden layout. I could have sat there many times for hours just being entertained by what was goinf on. What really caught my attention and made me realize it's potential was the tiny miniscule parasitic wasps which paracitize grubs, worms and catapillers from many pests. I don't know alot about various insect types or kinds, but from what I saw they were the type we find in the etomology mags for holistic plant health care.

      No problem about the copywrite stuff. Really appreciate your work.

      Thanks again.

    2. If you want to link, just link to a whole blog chapter, not an image. Just click on the title, it will be underlined, and the web address on top is then the permanent address for that particular blog chapter. I may even post one on Rhamnus when it blooms

    3. I've already created a post on my personal experience with Rhamnus californica here

      Attracting Beneficial Insects With Beautiful Landscape

      When you get your post and pics, I'll keep checking and link your page to mind.

      Thanks again, Kevin

  5. I found your blog on Blogger's Blogs of Note. I usually have one trip a year to Tucson, and will be there in mid-April. I also usually have at least one hike in the desert.

    I love your blog and your interest in insects, and your work on documenting them.

  6. I justamente LOVE all the pictures!!!! Saludos.

  7. I justamente LOVE all the pictures!!!! Saludos.

  8. Kevin
    I found out in the meantime that you are probably quite right with your observation. The alcaloids are in the nectar, and they do affect pollinators. Honey Bees did not coevolve with our kind of Datura (US) and the flowers are mainly 'night-active' which the bees are not. The color too: this is not a bee flower. So it's hard to tell which evelutionary significans the intoxication of an occasional be has. But the primary pollinators are Manduca Moths, and they get 'drawn deeply' into the flower, stay longer, and are sure to return. They love it, get addicted, and become super faithfull pollinators.