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Pure Green Augochlora

Augochlora pura


I was examining this very rotten stump for fungi when I noticed these small, metallic green sweat bees nesting in the wood. They looked like tiny, living emeralds. They had brilliant green heads, thoraxes, and abdomens that were covered with small white hairs. I identified these bees based on inspection of two distinguishing traits: (1) dark, oval shaped tegulae, and (2) the bee's faces had distinctive epistomal lobes where the parocular area extends down into the clypeus. I'm assuming the bees I spotted are mated females that are making nests in the wood.


I spotted several of these solitary sweat bees nesting in a rotting stump in a deciduous forest.


These bees are referred to as "sweat bees" because they like to lick sweat from human skin, most likely seeking salt. Electrolytes such as sodium are important for nerve and muscle function, in addition to a variety of other life processes. So, it appears that sweat bees imbibe human sweat in order to help them maintain homeostasis. Interestingly, as you can see in these photos, these bees are cobbling their nests together using galleries in the wood that were probably made by other insects. Within these galleries, the female bees will leave cakes made of pollen, nectar, and spit, which will soon be food for her offspring. It's thought that her saliva is added to the cakes because it has antiseptic qualities that help keep the food fresh and add extra protection to the eggs. After a brief interlude with a mate, she will lay eggs on the pollen/nectar balls. The nests are lined with a thin, impermeable membrane that she produces from glands in her body. The nests need this added protection because there are many predators that would gladly devour her offspring. When the larvae hatch, they consume the nutritious cakes. Once larval development is complete, they will pupate, and then emerge later as adults.

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Christine Y.
Christine Y. 2 years ago

Thanks for your comments Mark and Leuba. Yep, the bear has to survive just like all of nature's creatures. Circle of life.

Leuba Ridgway
Leuba Ridgway 2 years ago

Well done Christine for doing what you could do to protect the rest. The rest is nature in action I guess...

Mark Ridgway
Mark Ridgway 2 years ago

Oh no... that's nature I guess.

Christine Y.
Christine Y. 2 years ago

I have an unfortunate update on these bees. I went back to their stump to find it all dug up and mostly pulverized. There was bear sign nearby, and so I'm guessing that a bear dug up the stump to feast on the treats hidden in there as there were lots of ants, bees, and larvae in the rotting stump. I did see some sweat bees still in their cells though, and I gathered the stump remains and piled them back on top of the remaining bees to try to give them some protection from the coming cold weather.

Christine Y.
Christine Y. 2 years ago

Thanks Jonathan!

Congrats for the SOTD and ceratainly a great spotting and info.

Christine Y.
Christine Y. 2 years ago

Thanks so much Danièle! I'm so honored that you chose this beautiful bee for SOTD! Thanks also to Leuba, Mark, António, and Felix for your comments.

Felix Fleck
Felix Fleck 2 years ago

Very interesting and great shots! Congrats.

Very nice series Christine,congratas on the SOTD and thanks for sharing

Mark Ridgway
Mark Ridgway 2 years ago


DanielePralong 2 years ago

Congratulation Christine, you've set the bar very high again with this outstanding series of images and notes on Augochlora pura, our Spotting of the Day:



Leuba Ridgway
Leuba Ridgway 2 years ago

That is one great spotting Christine - the colour, the shots and the interesting information makes it an excellent spotting. Thanks.

Christine Y.
Christine Y. 2 years ago

Thanks so much for the nomination!

AshleyT 2 years ago

Your spotting has been nominated for the Spotting of the Week. The winner will be chosen by the Project Noah Rangers based on a combination of factors including: uniqueness of the shot, status of the organism (for example, rare or endangered), quality of the information provided in the habitat and description sections. There is a subjective element, of course; the spotting with the highest number of Ranger votes is chosen. Congratulations on being nominated!

Christine Y.
Spotted by
Christine Y.

Connecticut, USA

Spotted on Oct 23, 2017
Submitted on Oct 24, 2017

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