Battle of the Bees

Heriades truncorum. Photo by Dick Belgers, Wikimedia Commons

The number of bees we’ve identified from our summer collection topped 160 this week. We won’t finish identifying all the specimens collected before the deadline for my student’s final written report, but we’ll get through most of it. She’ll certainly have enough data to say some interesting things.

Between our garden and prairie sites, we’ve mapped out some twenty genera divided among five families. Within genera there are multiple species, but that likely won’t get sorted out until the spring. It’s been a tough journey, keying out all these organisms. One bee can take anywhere from a few minutes to hours. Even then, we have to wait for expert confirmation, at least in some cases, to make sure we got this right.

This week, though, I could tell how much I’ve learned as I whipped through a set of specimens under the scope. I know now the moment I look at a bee what characters to jot down, what will likely be important in determining its final identity. I also have a gestalt feel for where things belong in the grand scheme of bee classification.

Even the statement, “I haven’t seen this before,” is now useful information – because the list of bees I haven’t seen is getting smaller relative to the list of bees I have.

Since I began learning how to identify bees, one character has been the bane of my existence: facial foveae. Like bulerías in flamenco dance, facial foveae should be fun and whimsical. But they’re just hard, and I don’t get them.

“What are facial foveae?” you say.

I’m so glad you asked!

Facial foveae are shallow depressions found on the face of bees, just between the eyes. If you google “facial foveae,” you’ll find a diagram that shows where they can be found, with facial foveae clearly marked as stippled ovals. Something like this:


Should be easy, right? Except when you look at a real bee face, this is what you see:

Andrena fragilis,

Now, I ask you: How am I supposed to know whether there are foveae beneath all the fuzz on that cute little face? Especially when pretty much every bee out there has fuzz on its cute little face? You have to get the angle and the lighting just right and most importantly, you have to train your eye to recognize what you’re looking for.

Facial foveae tripped me up for the first time just over a year ago, when I sat down to identify my very first bee from Jerry Smith Park. I thought I saw facial foveae where there were none. As a result, I misidentified a species of Melissodes as Andrena – putting the bee not only in the wrong genus but the wrong family.

How could I make such an embarrassing mistake, you ask? Well, to give you an idea, here’s an example of what a Melissodes face looks like:

Melissodes trinodis,

Compare this image to the Andrena above, and you tell me: Which of these two is the obvious case of a bee with facial foveae?

Elementary, my dear Watson. It’s the first one, of course! Right? Right? 

See what I’m saying?

Now, as you work with bees not only do you learn how to see facial foveae, you learn there are other characters that can be used to distinguish one genus from another. Melissodes, for example, also have a particular color pattern to their antennae. But sooner or later, you have to nail down hard characters like facial foveae if you want to be a successful bee taxonomist.

This past spring, we collected several Andrena that finally allowed me to have a first-hand look at the “velvety facial foveae” that set them apart from all other bees. That made me a very happy camper and greatly shored up my confidence in my bee identification skills.

Summer passed. Autumn arrived. The number of bees I identified passed the 100 mark, then the 150 mark, and then a couple weeks ago, I ran into something that looked like this:

Heriades carinata, Discover life
Heriades carinata,

I sat back from my microscope and thought, “Okaaay…Are those ‘velvety facial foveae’ or is that just fuzz between the eyes?”

With this one question, almost all the confidence I’d gained identifying bees flew out the window. I mean, I didn’t think I was seeing facial foveae, but how could I be sure?

And if those were facial foveae and this was an Andrena, it almost certainly meant I’d misidentified the other bees from earlier in the season. Those bees had been large and fairly robust, while this one was itty bitty, black and bullet-shaped.

And if I’d misidentified that first batch of spring bees, for all I knew, I’d misidentified the last 100 bees I’d gone through because gosh darnit how am I supposed to know whether I’m recognizing all these crazy obscure characters correctly?!

Fortunately, nowadays biologists have more than one resource to work with when identifying our critters. In addition to Mike Ardhuser’s Key to Missouri Bees, which has been my primary reference for Jerry Smith Park, I use the colloquial but very handy The Bees in Your Backyard by Joseph S. Wilson and Olivia Messenger Carroll. I also have a list of bees previously collected at Jerry Smith. By cross-referencing this list with and my other resources, I was able to confirm my new bee belongs not to Andrena but to the genus Heriades, part of the family Megachilidae.

Heriades do not have facial foveae, just fuzz between the eyes. They are overwhelmingly cute, and not just because they’re tiny. They are widespread, but not many species are known; only three native species have been recorded east of the rocky mountains. These little bees nest in cavities in wood, or occasionally in pine cones.

Yes, that’s right – they nest in pine cones from pine trees. I guess that makes Heriades the original Christmas tree bee! So Happy Holidays, my bee friends from around the globe. May your winter nights be warm and joyful, and filled with fuzzy facial foveae.


4 thoughts on “Battle of the Bees

  1. Hi Karin, Love your bee posts. Remind me of my wasp identifying struggles. Are you using DNA barcoding for the bees, or does it not exist yet? Are you posting your identified bees on iNaturalist where specialists look at things? It is a wonderful resource. I wonder if whomever made the original keys really had to use fovea at the family level.

    Liked by 1 person

    1. Hi Joan! You know, when I was trying to key out the spider I worked with for my dissertation and beyond, I couldn’t even get it down to family because the character that supposedly defined Theridiids in the key – comb-like structures on the hind tarsi – weren’t present on my little spiders. When I finally sent them to the Smithsonian spider guy, he said, “Oh, yeah, they’re Theridiids,” and I said, “but what about the comb thingy’s on the hind tarsi? I’m not seeing any…?” and he said, “Well, all Theridiids have those except the ones you’re working with.” [eye roll] Wouldn’t that be just my luck?

      I think DNA barcoding is available for some wild bee species but not all; I have to do some homework on that again, especially before I try to start knocking this all down to species level. I signed up for inaturalist last summer but haven’t done too much with it yet. I need to set up a good stage for photographing my specimens in the lab. That’s on my to-do list.

      Can’t wait to see you and Dave! Just a few more days!


  2. I get all shivery-thrilly when I read the passion in your bee posts. Since we met, I’ve always thought of you as a writer. I knew you’re a scientist! But you’re a SCIENTIST! A dedicated, passionate scientist at least as passionate about this art as you are about writing. Maybe even more. So cool.

    Liked by 1 person

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