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Sunday, September 16, 2012

Metallic Green Bees – Genus Agapostemon





Have you noticed any interesting insects recently? It seems like we discover new insect visitors every time we look in Mother Nature’s Backyard. Right now our Plant of the Month (Sweet-scent – Pluchea odorata) is attracting a number of interesting insects (see above).


Late summer and early fall can be a good time to observe insects, depending upon the weather and the types of plants that are blooming. Some insects hatch in the summer and are active now; others are completing their life cycle in early fall. And all can provide hours of interesting viewing. One of the more interesting insect groups – and among the more showy – are the Metallic Green Bees in the genus Agapostemon. These are true native bees in the family Halictidae (the Sweat Bees). But they are quite different from the familiar – but non-native - European Honey Bees.

Metallic Green Bees are found in North and South America. There are about 40 species, with the greatest abundance in temperate regions and Southwestern United States. The Agapostemon are floral generalists, which means that they visit a number of different flower species. Despite their lack of specificity, generalists like Metallic Green Bees can be important pollinators in gardens and in the wild.



Metallic Green Bees are short-tongued, so they favor flowers with a relatively open architecture and easily accessible nectar, which serves as food for adults. Like all foraging insects, they appreciate the convenience of plants with many small flowers clustered together. This in part explains why you’ll notice Metallic Green Bees visiting plants in the Sunflower family (Asteraceae; including Sweet-scent) and the Buckwheats (genus Eriogonum). Both of these plant groups feature many small simple flowers that produce high-quality nectar.





You’ll recognize Metallic Green Bees by their unique coloration. Our local females are often metallic green all over while the males have a yellow-and-black striped abdomen (the rear segment of the body) and metallic green head and thorax (see photo above). They are medium sized bees (about 0.3 to 0.6 inches long) somewhat smaller and slenderer than European Honey Bees. You’re likely to see the females busily visiting flowers, collecting pollen on the brushy hairs of their hind legs. The males will be seen nectaring (sipping nectar) or slowly cruising flowers in search of females.

Most species of Agapostemon are solitary ground nesting bees, although individual bees may nest in close proximity. They build deep vertical nests in the ground or in earthen banks. Metallic Green Bees have two generations per year: the summer generation which is almost all female and the fall-spring generation which includes both males and females. Fertilized females from the fall-spring generation over-winter from late fall until early spring. These females accumulate a layer of fall fat that allows them to survive the winter (note: cold weather kills the fall-spring males, which do not have the fat layer).

Fall-spring females from the previous year emerge in early spring and lay eggs in cells in the underground nests. They provide each cell with a pollen ball to feed the developing larva. The early spring-laid eggs give rise to the summer generation, which is mostly female. The summer generation, which emerges and nests in summer, lays eggs that produce the fall-spring generation. Surprisingly, the fertilized eggs laid by the summer generation give rise to fall-spring females while the unfertilized eggs develop into fall-spring males. The fall-spring generation emerges in fall and includes both males and females. And so the cycle continues, from one year to the next.


The warm days of fall provide a wonderful time to get out and enjoy the out-of- doors. So get out in your garden – or in the wilds - and look for these interesting native bees.

49 comments:

  1. Howdy! This is my first visit to your blog! We are a group of volunteers and starting a new project in a community in the same niche.
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  2. We have had a green bee living in a door ornament for almost a year...seems unreal, but she is still there. I know because she makes a small opening to come out and then closes it at night. It's really amazing.

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  3. Then these four must have been sisters. Saw large "anthill" in brick walk in front yard but then saw these faces peeking out: http://www.flickr.com/photos/kaz52/8990030574/

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  4. Wow that's a cool picture of the nesting bees. I've recently seen a bunch of green bees on my sunflowers. I had never seen them before and they are amazing.

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  5. I just saw one of these in my garden.

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  6. I have many nests in my backyard. First also thought they were ant hills until I saw the green head pop up.
    Not sure that I like my whole yard filled with bee hills.

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  7. Thanks for the info!
    We just saw one of these bees flying and collecting some pollen from white clovers in our front yard. We had never seen one of these bees before and it is good to learn about this species from your posting ;)

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  8. Dartmouth Ma. Bees enjoying my cactus flowers

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  9. Just spotted this green headed bee in my Cone Flowers - I pinch off the Chinese Beetles, so spend a lot of time examining foliage and flowers in search of these hungry guys. I've only ever seen one. Do they sting? Powell, OH Observer

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  10. I just was searching the internet for "green metallic bees" and came across this post. I'm in Virginia, and there are alot of these on my Black Eyed Susans and Purple Coneflower...they are very busy bees. Very cool.

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  11. just saw 2,,how long have we had green bee's. I'm in my 50's an this is the first I'v ever seen or heard of.

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  12. Just saw one on a calendula flower! It had fat yellow legs and yellow antennae- Seattle, WA.

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  13. I just encountered these green bees for the first time. I was pulling weeds where my
    cone flowers and black eyed susans are when a swam of bees came out where I was sitting on the ground. One did sting me on my elbow and it hurts. I think one stung the cat too. She was walking near them and jumped about 2 feet high, turned to see what may have happened and then ran off. California, KY

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    1. We just noticed these bees in our yard because my husband got stung on his ankle while mowing-he said it does hurt quite a bit-do they make hills at the base of maple trees? We have a large hill at the base of our maple about 30 feet from the ground hole where he got stung and assumed it was ants until we looked up the bees online. Greenbrier,Tennessee

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  14. I always have honey bees in abundance because of the borage that is all over my garden, but I saw the green metalic bees for the first time last month on my artichoke flowers. They are a lovely addition to my NW Oregon garden.

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  15. I live in NC and walked into my kitchen and stepped on one. I have never seen anything like it so I put it in a paper towel and showed my husband. They are beautiful. Just a lttle odd since I didn't even know they existed.

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  16. In Florida they collect nectar and pollen from a small palm with the common name saw palmetto. Here is a link to my photo taken on May 26th 2014.
    https://www.flickr.com/photos/71477136@N04/14091606660/

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  17. I just encountered one today, I got really scared because it landed on top of me while i was relaxing in our back deck. My family allergic to most of insects, I think I accidentally killed it. I feel so bad now.

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  18. I live in the pacific northwest and I just found a hill in my back yard.... now to mark it so the husband doesn't mow over it.

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  19. Photographed these beautiful insects this morning in my backyard. They were all over the wildflowers that grow naturally in the yard. I had never seen one before and didn't even know that bees came in so many colors! I love nature!!

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  20. Seems strange that this is the first year so many people including myself have seen these beautiful creatures. They're like a house fly and a bee crossed genetically. Maybe an answer for the microwave frequencies? IDK,

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    1. Exactly what i was thinking. Ive never seen them before and i love biology and the outdoors.

      I wonder if the european honeybee collapse has something to do with us noticing more of these flying around

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    2. I agree, seems strange they are being spotted by so many people recently. And they do look like some kind of mutant. I'm glad I looked it up so I know they're actually a species, and it's a good thing.

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    3. I just saw my first one today as well!

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    4. we have a huge amount of honey bees this year in south florida, plus a lot of these green bees,...glad to see the bees making a comeback,...

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  21. I have a rather large nest of them in my front lawn and horse pasture. I had never seen one before so I took some pictures and posted them on facebook. Does anyone know how deep they nest? We get some pretty cold weather and dont know about the survival rate of a nest. They really are quite pretty. I live outside of Kelso Wa up in the hills.

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  22. Just found a green bee in my house, looks larger than a normal bee though and has amazing colors.
    -Gold Coast Australia-

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  23. Here in florida, I've never seen these before now, but they are beautiful.

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  24. I have one that hovers over my jasmine bush in my backyard just off of my deck and has done so for over a year, every morning, aside from the colder months. It does not leave when I am out there. If I get too close, it darts a bit then settles back in. I noticed a second one last week for a couple of days but have not seen it lately. Does anyone know how long they live?
    Sarasota, FL

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    1. These bees don't hover like a helicopter.

      There is a fly that does this though. I see them in the forest a lot, and they like beams of light for some reason. They look kind of like a wasp, but they are harmless.

      I was impressed at its maneuvering skills

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    2. Sounds more like a carpenter bee.

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  25. They live at most about a year. It depends on their sex and what time of year they hatch.

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  26. I got out of my shower and heard a buzzing sound and looked up , there was a male bee with a green back. It is unique for sure but I did get rid of it since I was worried about my young kiddos getting stung. We just planted Bogan villas and jasmine and maybe that's why but a guy two streets down is also nesting bees for honey In his yard. Could this be why we see it more than because we have flowers?

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    Replies
    1. Yes, having more flowers on your property attracts bees and butterflies.

      Without bees many fruits and flowers would bloom.

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  27. I'm in CT and it's the first year I've seen these little bees.They are around my catnip flowers and squash blossoms. Pretty cool looking.

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  28. This is the first year I've seen them,too.Cool looking little bee.Seems like they are all around the country.I'm in CT. They seem to like my catnip flowers and squash blossoms.

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  29. I just saw a metallic green bee fir the first time, on the bee balm on my front porch today, and had to come look it up on the internet, because it looked surreal. like something out of Transformers. I almost thought maybe it was some kind of little sci-fi drone, it looked so unusual. Glad to see from these comments that they are common now. I have never one like it before in my life, and didn't know what it make of it, except that it looked like a cool little robot bee. :)

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  30. Saw something very much like this today here in Central Florida...HOWEVER...the abdomen was not yellow and black but GREEN and black with pollen sacs on the legs

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  31. I just got bit/stung by one yesterday & it hurt so bad! Does anyone know if they are poisonous? & what can I do to treat my bite/sting

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  32. We had more last year (more of with yellow/balck striped back part) found on the lavender bush. Think they can feel the autofocus as did better just staying near a flower and taking a pic when found them on it.
    Many years ago, would sit in garden and they(all green) were on the basil, and some really tiny bee's. Some bees were cutting circles out of leaves and would hold them to underside with their middle legs and zoom off. A small (think green metalic) had made a home from the ground hole of an outlet outside. Really is amazing what you see/hear when just watch/listen !! (espec if dont spray and poison yard...)
    Stings- carfully remove stringer since if stinger sack,might squeeze more into person. My mother used mud(it didnt help). Have heard ice, antihistamine,sugar poultice,seaweed(tried,for me it worked great), baking soda. Thank you for the info Lynn

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  33. I have never seen this bee before and it took me by surprise! Especially against the yellow buttercups that my wife has planted. But I never thought of Minnesota as temperate. Thank you for your description of these interesting bees.

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  34. I saw one today in he community garden next door. We are in Denver, CO. I thought it was a fly at first.

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  35. I saw one on my liatris early this morning, what a little jewel! Was able to identify it as a male thanks to your blogspot.

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  36. I just saw my first one today. Love in Illinois. Solid green so female? Beautiful. This blog help me identify it. Thank you. Would like to see want a nest (hill)looks like. I have two small dogs and would hate to have them stung.

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  37. Thank you for your blog. First time I saw this type of bee. And you gave me the info I needed. Would like to see their nest tho. I have 2 small dogs and would hate for them to get stung or to disturb the nest. Pls send pic. Thank you.

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  38. I have to say I hate these little bees. I accidentally disturbed a nest and was stung so many times and so fast I had to go to the hospital. A second time, when I was mowing the lawn, the mower scared another nest and they swarmed on me. They are pretty and serve a great purpose, but they are highly territorial. Their stings hurt for days. Be careful.

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  39. Anyone know how deep the nests go? We're putting in a sidewalk that will go over the small (5-hole) colony I've been enjoying all summer. Wondering if it's feasible to dig up and relocate the nest in the dead of night while they sleep.

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  40. My husband just got stung by one,today it seemed to sting him multiple times....do they have more then one stinger? This is the first time we saw one!!

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  41. I just told my husband, if I pass out, I was stung by a green beelike insect. That's what I saw and now can identify from your helpful website. Fortunately, I'm not allergic but it does hurt. Watering flowers in front area. I live near Microsoft.

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