By Camden Thomas, Restoring Lands Field Coordinator
While walking through a park or perhaps admiring your garden, have you ever stopped to take a good look at our friendly bumblebee pollinators? Here in Southeast Wisconsin, you may have been lucky enough to have spotted a rusty patched bumblebee! The rusty patched bumblebee is an especially important bumblebee because it is the only federally endangered bumblebee not only in Wisconsin, but the entire U.S. The rusty patched bumblebee was once common across the eastern U.S. and upper Midwest, but has declined in population by 87% in the last 20 years. With such extreme population declines, you would think that it would be quite a rare sight to see one.
However, Southeast Wisconsin happens to be one of the last strongholds for the rusty patched bumblebee. While it is certainly a far cry from the most common bumblebee you will see in your garden or on your walks, we are lucky to live in a region that we can stumble across these wonderful endangered bumblebees. Here at Restoring Lands, we have been doing bumblebee surveys to get a better understanding of what bumblebees use our preserves, and we have been successful at finding the rusty patched at five of our preserves so far!
Why should we care about the rusty patched bumblebee?
In the last 15 years or so, pollinators have been catching on in popularity and many people have become aware of their important ecological functions. Many of our foods and flowers must be pollinated to reproduce and grow the fruits and vegetables we eat. Our pollinators are the heroes who often go unnoticed in their extremely important duties. Some examples of foods that depend on pollinators are: Apples, strawberries, cherries, blueberries, raspberries, peaches, onions, tomatoes, squash, cucumbers, and many more. But we have many other bumblebees and other pollinators, so why does the rusty patched bumblebee matter? Different species of bumblebees occupy different niches in the ecosystem and focus on different species of flowers.
If the rusty patched bumblebee were to become extinct, we would lose the niche that the rusty patched bumblebee fills, and there is no way to get it back. It would reduce the diversity of pollinators in our ecosystem, and if another common bumblebee species had a major population decline due to disease or other ecosystem issues, the loss of the rusty patched could be disastrous for our plants that require these pollinators. The massive decline of the rusty patched bumblebee could also be a harbinger for what is to come for the rest of our bumblebees and studying the rusty patched could be the key to preventing these issues in the future.
How can I help the rusty patched bumblebee?
Keep dead grass, brush piles, and fallen leaves through the winter as these are all areas that bumblebees use to hibernate and survive the harsh cold. Refrain from spraying insecticides as these insecticides often harm unintended animals such as our bumblebees. Keep a garden of native wildflowers that bloom throughout the seasons to give our pollinators a healthy food source. Some good wildflowers for bumblebees are: Anisse hyssop, common milkweed, cream indigo, white and purple prairie clover, culvers root, sweet joe pye weed, bergamot, mountain mint, Virginia waterleaf, wild geranium, shooting star, new England aster, Canada goldenrod, calico aster, etc. Early spring native flowers and trees are especially important as the new queen bees emerge and search for food and nests to start their colony for the summer. Having abundant early food sources are critical for their survival.
How to identify the rusty patched bumblebee
Luckily, the rusty patched bumblebee is fairly easy to identify compared to other bumblebee species due to its namesake rusty patch. On the second segment of the abdomen, female workers and males will have a characteristic reddish-brown to orange patch. It can be distinguished from other bees that have brown and orange hairs because on the rusty patched, the rusty spot is completely surrounded by yellow hairs. On other species such as the brown belted or the red belted bumblebees, their brown and red hairs will touch the black hairs of the abdomen. The rusty patched is unique in that the rusty patch is surrounded by yellow hairs.
Another characteristic to look for is a black “thumbtack” of hair on the top of the thorax. Several other species of bumblebee also have this “thumbtack” design, however it is a great secondary feature to look for if you might not have a great view of the abdomen. One more note to keep in mind is that many queen rusty patched bumblebees lack the rusty patch and just have yellow hair on the first two abdomen segments, which is a great time to look for that “thumbtack” pattern on the thorax.
A good tip to getting a good look at a bumblebee is to take a video and then look for specific frames in the video to see identifying markings. If you are interested in learning more about bumblebee identification, bumblebee resources, or reporting bumblebee sightings, please look into the DNR’s bumblebee brigade website https://dnr.wisconsin.gov/topic/WildlifeHabitat/BumbleBeeBrigade.
