December 2022 Bulletin

Crazy Corbiculae

Latin for “little basket”, corbiculae have evolved to carry pollen by the bushel. These concave parts of the tibia are fringed with hairs that help to keep the packed pollen secure to the leg. As the bees use their forelegs to clean themselves, they rub those legs on their hind legs, pushing the pollen through a comb of short hairs at the base of the tibia. Sometimes, they will add a little moisture from their tongues to the make the pollen stick together better. The hairs that run along the sides of the tibia (labeled “fringe” hairs in the figure above) keep the pollen pack from falling off while they fly (What a bummer that would be!). The pollen pellet can weigh as much as 30% of the bee itself. However, the strength of the hold by these hairs is estimated to be 20x higher than the force normally experienced while flying!

Only four groups of bees have corbiculae: affectionally, bumbles, honeys, stingless, and orchids. They are (not by accident) also highly social bees. Theory predicts that their social nature favors carrying large quantities of pollen that can be “popped” off relatively easily and stored in a colony of multi-generation family units. To learn more, check out this recent article on the topic.

Examples of bee with corbiculae (clockwise from top left) Apis dorsata, Bombus pauloensis, Melipona quadrifasciata, and Exaerete smaragdina. Note: Images are not to scale. Photos by Eduardo Alemeida, Ph.D., University of São Paulo

iNaturalist Year in Review

Every year, iNaturalist puts out an amazing infographic about how you interacted with iNaturalist in the last year. On it, you can see how many species you posted and your pattens of posting compared to last year. For example, Nina mostly posted observations of bees (no surprises there), and 99.9% of her identifications for others were also bees.

To see your year and review, log onto the website and click the green “see my personal year in review button” or copy and paste the below URL, and replace “your-username” with your account name.

Let us know if there’s anything that surprised (or delighted?) you about looking at your stats!

Nina’s breakdown of species observed

Bees Around the World

This fall, Colleen Crank and Wayne Hause got to travel a bit and found some cool bees along the way!

In New Mexico, Colleen documented this beautify male Hunt’s bumble bee (Bombus huntii). This species often has a “trimmed” look with hairs short and even, but this male looks a little messier. He still has the tell-tale color patterns on the back of his thorax and on his abdomen. For more about this species check out Bumble Bees of Western United States by the Xerces Society. It’s free to download and print!

In Japan, Wayne and his wife saw these cuties busily foraging. The first is an Andrena or Colletes (we can’t quite see if there are “eye brows”, aka facial fovae, or not) and the other two are flower flies, perhaps in the Syrphidae Family.

Thanks for sending the photos! We love seeing organisms from all over the world – especially when everything around here is “resting” for the winter. Have you seen something extra cool during your travels or in your neighborhood? Send them our way, and we’ll share them with the Shutterbee community.

iNaturalist Data Cleanse

For Shutterbee, we rely on photos getting to a certain taxonomic resolution depending on the group. For some bees such as bumblebees, we only incorporate photos that are species level, whereas most bees we use genus level. One thing that’s great about iNaturalist, is that the data can constantly improve. One way you can help us (and improve your data!) is to occasionally go through your posts and see which ones are languishing at a higher taxonomic resolution.

There may be a few reasons why the photos have not made it to tribe/genus/species

  1. The photo quality wasn’t great. This happens to all of us, we know those bees don’t like to sit still! For these photos, you often won’t see any IDs on it and they cannot improve.
  2. There’s disagreement between identifiers
  3. There’s photos of multiple bees in the post (e.g., Photo 1 is a honey bee and Photo 2 is a carpenter bee)

Fortunately, there are some ways to improve your data in the cases of #2 and #3.
[Note: if this seems too daunting for you, don’t worry about it! We wanted to instruct people on how to do it, but this is not a requirement.]

First, you need to find all your observations that meet the criteria. The easiest way is to log on to your iNaturalist on the browser version and then click this link, changing out “username” at the end of the URL for your username.

You will then be in the identify section of the website. Click on the first photo, and then you can use arrow keys or click the arrows to go through your observations.

If your ID differs from everyone else’s, you can click the little arrow next to your ID and then click “Withdraw.”

Click the down arrow and then “Withdraw” to remove your ID.

If your observation has photos of multiple species (not just multiple bees in a single shot but essentially two+ observations mashed together) There will usually be a comment by someone saying so. For these, photos do as follows:

Where the “View” button is located

1. Click the view button at the top, this will open up the observation in another window
2. Click the blue “Edit” button on the top right.
3. Uncheck any photos that are of a different species
4. Click the blue “Save Observation” button at the bottom

Cleaning up your postings is totally optional! If this is challenging for you, don’t worry about it. If you need some additional help, you can email Nina ( or send her a message on iNaturalist (tockgoestick).

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