Ceratina pacifica

Prior to studying bees, I thought that all bees were round, fuzzy, brightly colored creatures. As many readers will know by now, I was definitely mistaken! While bees come in many different colors and forms, the family Apidae (which includes our honey bees and bumble bees) does include a large number of rotund, fuzzy bee species. However, even in this family that includes such familiar members, there are many exceptions.


The photo above is a female small carpenter bee, Ceratina pacifica, collecting pollen from the blossoms of a California thistle. Measuring about 9mm, she is not actually all that small by the standard of bees (and certainly large compared to many of the other small carpenter bee species)—but she is certainly dwarfed by the large carpenter bees in the genus Xylocopa, which can attain the size of large grapes. As one may guess by their similar names, the small carpenter bee and the large carpenter bee are cousins—they are both in the subfamily Xylocopinae.


This photo above is a male Ceratina, probably Ceratina pacifica but also possibly its closest relative, Ceratina punctigena. The males are very hard to tell apart from each other and can only be distinguished with difficulty under a microscope. One can immediately tell that it’s a male, though, by its white “lip” (clypeus). The shape of the white mark kind of reminds me of the Joker from the Batman movie, The Dark Knight—except inverted in color.

Small carpenter bees excavate the centers of woody stems to construct their nests. In the summer and fall, young females would bore into woody stems to hibernate, and the following spring or summer, these females would fully excavate their winter homes into functional nests and begin collecting pollen. We have roughly 20 species of Ceratina in North America, so I will write more about them later.

By the way, the photo of the male bee was taken using a 1000mm macro lens that photographer John Gibbins lent me for the day as we photographed bees together at Cuyamaca Rancho State Park for an article in the UT San Diego newspaper and website. I think the link to the news article on the UT website is now only available to subscribers, but here’s a text copy of the article hosted on a different website. Enjoy! And thanks John for the photography tips!

Leiopodus singularis

About a month ago, I had the pleasure of leading a small team of undergraduates to survey bees during what will hopefully become the annual Bioblitz at the Lake Hodges trails in Escondido/Rancho Bernardo, CA. Even though the weather was very suboptimal for bee activity (it was overcast and even rained at one point), we did find a highly noteworthy bee species: the chimney-bee-cuckoo, Leiopodus singularis.


Huge thanks to botanist and photographer, Dale Hameister, for taking the above photo of this male Leiopodus I found foraging on mustard blossoms. As far as I’m aware, this is the only photo of a properly identified, non-preserved male Leiopodus on the internet. Way to go, Dale! As its species epithet suggests, this is a singular, lonely bee. This is the only member of its genus found in North America; all the other Leiopodus species are in Central and South America. Leiopodus is the only genus in the bee tripe Protepeolini.


The above photo is, to my knowledge, the only photo of a properly identified, non-preserved female Leiopodus on the internet. I took this photo at Mission Trails Regional Park, which has some of the nicest coastal sage scrub ecosystems I’ve ever seen. I highly recommend going on a hike there in the spring!!

Even though this is a rather widespread bee species (it’s found in all four US states bordering Mexico, south through Guatemala), it appears to be locally quite uncommon. This bee is a cleptoparasite of the mallow-loving Diadasia species (such as, potentially, the aforementioned Diadasia nitidifrons), and thus I have only seen it in places where chaparral bush mallows (Malacothamnus fasciculatus) occur. I think the fact that Dale and I have taken such rare live photos of this bee species really highlights how much science still needs to be done to document the diversity and distribution of bees, even in pretty familiar localities like San Diego. I mean, scientists have discovered new bee species even in the heart of New York City!!


I had the pleasure of helping to lead a pollinator-themed hike at the SD National Wildlife Refuge today alongside Lisa Cox and John Martin. The drought hit the San Diego ecosystem rather hard, and a lot of plants that should be leafy and blooming are dead and dry this year. No doubt some perennial plants were killed by the drought, whereas others did not grow fresh foliage or did not attempt to bloom. Likewise, many annual plants either did not bother to germinate, or were stunted or killed by the dryness (and possibly by the immense heat wave that swept through the region this past week). However!! There were still a few things blooming and we did get to see some pollinators!


The bee photographed above is a male Hylaeus. One could immediately identify this bee to genus based on its sleek black form and pale markings on the face. Males tend to have extensive markings, while females often have just two little strips on the insides of the eyes. This feature earns this bee genus the common name of “yellow masked bees,” although a good number of species have white markings rather than yellow (like the handsome fellow photographed here). I’m not going to attempt identifying him to the species level because Hylaeus species around here all look so similar to one another, even under the microscope!

Hylaeus is unique among bees in that the female does not carry pollen using specialized external body parts (such as pollen baskets or pollen brushes). Instead, she swallows pollen grains and regurgitates them back at her nest (which may be tunnels in wood, holes in the soil, or a variety of other cavities they can find). For this reason, it has been really hard to study what plant species serve as the pollen sources for Hylaeus species—as one would need to either dissect foraging females (as my academic elder sibling Professor Erin Wilson at UC Riverside had done during her PhD at UC San Diego), or examine pollen in excavated Hylaeus nests. Hopefully, the Hylaeus species photographed above accepts pollen from the plant this specimen is sitting on (Eriogonum fasciculatum, a.k.a. California buckwheat), because it’s one of the very few plant species blooming in the environment!

Oh! By the way! I just changed the setting to allow for readers to ask questions! So, please feel free to do so! :-)

tumblrbot asked:


I remember bits and pieces of staying with my grandparents when I went to stay with them as a 2-year-old, to give my parents some space when my younger brother was first born. My grandparents lived in Tainan at that time, and they would make buttered mantou for breakfast, take me on walks to the nearby university, and watch Kimba the White Lion with me. Fun times! :)

Diadasia nitidifrons

This dashing blue-eyed blonde is Diadasia nitidifrons, whose name means something like “thoroughly hairy thing with a shiny forehead.” You can see both of these characteristic in this photo! Bees in the genus Diadasia are sometimes called “chimney bees,” because females have a tendency to construct chimneys out of soil that lead from their underground burrows. 

As with many other Diadasia species (most of which are found in the American Southwest and Mexico), D. nitidifrons is a specialist pollinator of the Malvaceae (mallow family). In San Diego, this bee is most often found in scrub habitats foraging on the chaparral bush mallow (Malacothamnus fasciculatus), although it also visits checkermallows (Sidalcea sp.) and apricot mallows (Sphaeralcea sp.). There are a few other members of the Diadasia genus that specialize on other plant groups—I will discuss these in the future too! :)

The next time you walk past a nicely blooming chaparral bush mallow, take a look inside the flowers—you may find a cute little Diadasia staring back at you!

Bee faces!

I was recently asked by UC San Diego’s Geisel Library to put together a San Diego native bee display. Since the specimens that will be put on display will be behind two layers of glass, it will be a little difficult for the audience to get close enough to the bees to get to know them personally…so I took a bunch of microscope stacked images of bee faces that will play on a monitor next to the displays so passersby can have a more intimate look at our amazing bees!

The above face belongs to a worker California bumble bee, Bombus californicus, which is closely related to the Sonoran bumble bee in my last post. The  long, black face of this species looks very, very similar to the more common and widespread yellow-faced bumble bee, whose face is much less elongated.

This face belongs to a male small carpenter bee, Ceratina punctigena. The white “lip” is the clypeus of the bee, and interestingly, having a yellow or white clypeus is common in males of many different bee genera in different families.

This squat face belongs to a female sweat bee, Halictus ligatus, which looks unremarkably like any other sweat bee in the genera Halictus and Lasioglossum from a distance, but its mugshot looks different from most of the other sweat bees.

And of course, how can we forget the many brilliantly metallic bees we have in San Diego, right? This beautiful blue-green face belongs to a female mason bee, Osmia aglaia. There are quite a few different metallic Osmia species in San Diego, and until my friend Dr. Molly Rightmyer drafted a key to the species, it was really difficult to tell them apart from one another.

There are plenty more faces (in fact, about 60 more) where these come from! I will try to upload them a few at a time after the exhibit at Geisel Library goes live—this is just a sneak peek.

Also, a HUGE THANKS to Rhea Brady of the Torrey Pines State Reserve Docents Society, who graciously gifted me several beautifully hand-drawn pictures of flowers and bees for the blog. I’ve used one for the header and will try to work others in somehow.

Peace :)

Bombus sonorus

Before I became hopelessly engrossed in the study of native bees, I really only knew of two kinds of bees: honey bees, and bumble bees. I had seen and even caught lots of other bees before, but had always thought of them as small wasps or winged ants. In my many discussions with others about bees, it seems that this is a pretty common scenario—for the most part, no matter how little a person cares or knows about bees (or insects in general), one usually knows that there are bumble bees, and that they are distinct from honey bees. That’s a great start!


The bee photographed above, Bombus sonorus (the Sonoran bumble bee), is one of the five bumble bee species that reliably occur within San Diego County (there are a few more on record but they seem to be much rarer). Like other bumble bees, it lives in a “primitively eusocial” colony. What this means is the following:

1)  A single queen establishes a nest by herself

2)  The queen will work hard to forage for pollen and nectar to raise her first few offspring

3)  Once the first batch of offspring come into adulthood, they will start foraging and tending to the colony, and the queen can then stay back and produce eggs

4)  There’s usually little specialization of tasks (unlike in honey bee colonies); most workers will do a variety of similar thing to maintain, provide for, and defend the colony

5)  There’s usually little outward difference between the queen and her offspring; most of the difference is in the size and development of ovaries (queens are bigger and have more developed ovaries)

6)  The queen lives for about a year, and thus so does the colony; at the end of each year (not necessarily following the Julian calendar) new virgin queens leave the nest, mate with wandering males, and find a place to rest, where they will stay dormant until the beginning of their nest-building season.


The Sonoran bumble bee is distinctive in its extensive yellow fur and very large size (the other yellow species, Bombus melanopygus, is very much smaller). In fact, it is one of the largest bumble bee species around here, with queens exceeding the size of most of our large carpenter bees. This species is also interesting in its seasonality: most of our other bumble bee species are active in the spring, but the Sonoran appears to be active in the late summer and fall. Unfortunately, this species seems to be in decline in San Diego. The San Diego Natural History Museum used to have records of this bee occurring throughout the County, including places like Balboa Park, but in the last 3 years of searching, my research group and I have only documented this bee within a narrow stretch of the coast. We don’t really have a clear understanding of why this has occurred, but hopefully we don’t lose this majestic species for good.


The beginning of the spring season is defined differently depending on one’s culture and climate. For me, it’s spring when I start seeing Andrena, commonly known as mining bees. In fact, the earliest solitary bee I’ve ever seen was an Andrena male, basking himself on a mission manzanita leaf on January 18, 2013 (made possible by the mild winters in San Diego). For female humans, the name Andrena means “strong,” “virile,” or “brave” in Greek, which could certainly apply to some of the earliest-flying of this genus, who have to brave the harsh cold weather to collect pollen and construct nests. However, it’s probably likely that this bee genus obtained its name from the Greek “anthrene,” meaning “wasp” or related buzzing insects. Given that it’s one of the most abundant and diverse bee genera in the world, it’s not surprising that the genus would’ve obtained such a generic name from biologists in the 1700s.

I photographed the above male Andrena out at Anza-Borrego desert last Saturday during a collecting trip. The morning started out very cold and windy (though sunny) and despite many plant species blooming, we saw no bees until about 10AM. But as soon as 10AM hit, these male Andrena snapped out of their torpor and began flying around. As with most males of solitary bees, male Andrena do not participate in constructing nests or collecting pollen and nectar. Instead, they patrol flower patches, waiting for females to arrive, and then pounce on the females to mate with them. In this sense, they are pretty much just a flying pair of eyes and testes.

I was lucky this past week and got TWO photos of Andrena! This one was shot on a cool morning in Gonzales Canyon near Torrey Pines High School. This is a different species of Andrena from the first photograph, and is a female. Cool mornings are great for photographing insects because it’s a good combination of actually finding insects because they’ve woken up and started working, and having enough time to snap the photos because they are still sluggish from the cold.