There are 4,000 species of native bees in the U.S., but how to tell them apart?

Though we focus on studying honeybees in the bee lab, there are a multitude of native bee species. Scientific inventory, monitoring and other research on native bees is gaining momentum as their important role in ecological conservation becomes more clear. This past June, I spent most of my time in the bee lab “processing”, pinning, and organizing samples of native bees collected as part of an ongoing bio-monitoring project at the Bernard Field Station. “Processing” meant washing the samples in a somewhat elaborate setup (credits to the USGS Bee monitoring laboratory) involving dishwashing soap, mason jars, and a hair dryer. As someone who had never vigorously washed and blow-dried dead bees from 9 to 5 for a couple of weeks, it was a strange experience that at times produced…delirium? Maybe that’s why, this semester, I wasn’t particularly eager to open the collection boxes into which I’d pinned the samples for further identification – though fortunately, one of my peers who has experience with bee identification was glad to take the lead on this project.

Boxes on boxes of pinned bees and information about where they were collected.

When we met to talk about the process of sorting the samples into appropriate phylogenetic categories, it became clear to me how useful and important it was to have clean samples to look at, and all the time I spent blow-drying them made more sense to me. As it turns out, identifying bees even to the level of genus involves evaluating minutiae: characteristics such as the shape and number of cells in a bee’s wing, or the presence of pollen-collecting or other hairs on the body of the bee give the kind of precise information that we need, and they can be difficult to spot. For our purposes and experience levels, we found that the best tools for identifying these bees are Discover Life and an identification book for bees native to California. The identification book is especially helpful since Discover Life seems to have a more extensive catalog of species found on the east coast, less so of species in California. Even so, it’s pretty helpful since it enables a user to narrow down a list of potential classification using a combination of the characteristics they are able to assess. For example, here’s a brief walk-through of how we would identify this bee:

The setup for evaluating characteristics of a bee using a microscope

For most samples, it is relatively easy to categorize them into a family based on some easy-to-observe characteristics. Given this pictograph, we can determine from the eye shape/orientation and wing shape/details that this particular bee belongs to Halictidae.

This narrows down our possible classifications. Next, we’re given a number of other characteristics to evaluate, sometimes as simple as determining whether a trait (e.g. pollen-carrying hairs on the abdomen) is present or not, or as meticulous and variable as the length of the bee. Depending on the sample, some of these determinations may just be too difficult to make – it’s hard to count the number of cells in a tiny, bent wing. But usually informational diagrams and explanations are offered to help with the trickier ones.

A few of these determinations in combination with each other typically narrow down the possible classifications to fewer than 10 or 15, at which point it can be easier to turn to the identification book, or turn to photo comparisons on Discover Life. From these images, it seems like our bee probably belongs to Augochloropsis, a genus containing beautiful metallic and iridescently colored bees.

This particular bee is pretty distinctively colored, so we’re able to narrow down its classification to just a few possibilities. However, the majority of our bees aren’t as flashy – and are smaller, making it more difficult to see little details. Here are a few of my favorites:

So why go to the trouble of identifying all these native bees? There are actually about 4,000 native species catalogued in North America, though not all of them have been named and on the whole they’ve been relatively understudied. Although public concern for bees in general has centered on Colony Collapse Disorder in commercial honeybees, native bees – notably bumble bees – have also suffered steep declines in recent decades. Native bees, which tend to be more specialized pollinators than honeybees, are particularly affected by loss of native habitat. Pesticide usage may be another significant cause of this decline. This is alarming because they are responsible for the pollination of native habitat – and are therefore also essential to the conservation of native habitat. In order to better understand that conservation, and the pollination networks in native habitats, we need to know more about native bees. To read more about how you can be involved in helping native bees, check out http://www.nativebeeconservancy.org/.