I was surprised to find a female sweat bee, on our back porch this afternoon. One of her wings had gone wonky and she was trying to get it back into the right folded position on her back. (You can sometimes tell the females from the males by the fact that the female’s legs are so hairy.)
There are several different genera of sweat bees and over 150 different species, so identification can sometimes be tricky, but I think our visitor was either a Pure Golden Green Sweat Bee, Augochlora pura, or maybe a Peridot Bee Augochlorella pomoniella. I’m basing that on her overall coloring and the fact that her tegula (the bit where her wing attaches to her body) is dark rather than green (like they are in the genus Augochloropsis). I’m leaning more toward the Peridot Bee because it’s found throughout California, whereas the Pure Golden Green Sweat Bee is usually found in the eastern US (on the other side of the Rockys).
According to the US Forest Service:
“… Augochlora makes her nests under the loose bark of old trees. Where you see a fallen log on the forest floor female Augochlora see valuable real estate. She builds cells made of mud and debris found under the bark that she glues together. She works throughout the days gathering pollen from her favorite flowers, carrying it back to her log home on her hind legs. In her nest, she mixes the pollen with some nectar and her own saliva. Scientists think that her saliva has antiseptic qualities that help keep this food fresh and add extra protection to the eggs. Once she has gathered enough food for one larva she lays an egg inside the cell and seals it. Her nests are lined with an impermeable thin membrane that she produces from glands on her body. The nests need all this protection because there are marauding ants and many other little predators that would promptly devour her babies; bee larvae make delicious meals for hungry predators. ..” CLICK HERE to read more.