I found these bees clinging together in a group in my yard just before a thunderstorm. Apparently, while the females of these solitary bee species nest in the ground, the males often sleep together in groups on vegetation. During rain they will cling to plants to weather out the storm. I believe these are longhorn bees, but I'm not sure what species.
Native bee species need plants to survive. They rely on native plants as a food source but also as structural support for daily living. Lawns of non-native grass offer little if anything in the way of food or habitat for our native insect populations. The plant these bees are clinging to is in the Asteraceae family (sunflowers, asters, goldenrods, and many more). I'm not sure what species this particular patch of plants is, but I've left it to grow in our yard out of both curiosity and as habitat for local wildlife.
Many of us who are fortunate enough to have yards are still bound by ecologically unfriendly HOA restrictions and city ordinances that require lawn maintenance. We should push to change those laws but there are still things we can do in the meantime. For instance, I planted a patch of goldenrod in my front yard and I put a border around it to make it clear to the city that it is a flower bed. At the end of the summer, I leave the goldenrod stems in place. This provides habitat for the insects that need those branches as homes for the winter.
Another great way to make habitat for bees is to maintain a brush pile. Instead of sending branches and sticks to the landfill, I have a brush pile against the fence in my backyard. Carpenter bees and other insects make their homes in this pile and the birds in my yard love hunting for insects there and gathering nesting materials during the Spring.
