Sweat Bee Life

From the archives (upstate New York):

This summer I stumbled upon a sweat bee nest while moving some old boards. The nest was between two boards and this is what it looked like when I lifted the top one off. (Sweat bees, family Halictidae, are often metallic, shiny green or blue.)

Sweat bees vary from solitary to social. This nest had multiple adults, which probably indicates they were living socially. Does anyone recognize the species?

All life stages were present. In this cell there is a ball of food and what looks like an egg (it seems to have a knob at one end?). Usually the food is a mixture of pollen and nectar, hence the yellow-orange color.  See the water beads in the cell? The sweat bees line the cells with wax.

The older larvae are plump grubs. Prior to pupating, the larvae enter a resting stage called a prepupa.

Sweat bee pupae look like most bee pupae. You can see their eyes, mouthparts and antennae. This species does not appear to spin a cocoon.

Everything is pretty neat and tidy.

I tried to replace the board, but when I checked the next day, it was obvious the disturbance was too much. Many of the cells were empty.

The nest was overrun with snails (I think they ate the larval food),

millipedes, sowbugs,

and of course, ants.

What a difference a day makes in the life of a sweat bee.

10 thoughts on “Sweat Bee Life

  1. Ossein

    Augochloropsis metallica/Augochloropsis sp. would be my very first and totally per-Quickmodus-aquired answer to the question of species. And if you're very fast, and fortune let's the blind man see, and I am right, then you could still make me a Xmas present just on time ;-))

  2. Júlio

    Really beautiful photos...
    I have some doubts about solitary Hymenoptera...
    What's the sex ratio of a solitary species of Hymenoptera? What about the male's life in such species? I know somethings about the figwasps, but they seem to be a very specific case...
    Does a queen exist when bees or wasps are living in a social system, but not that social?

    PS. I've been following the blog for some days and I hope I'm not bothering with the basic questions...should I use the AntQuestion page?

  3. Roberta

    Post author

    Ossein, you are definitely fast. :-)

    In the solitary bees that have been studied, when they are in the social phase (and some species can be social or solitary under different environmental conditions), they do have a "queen" and workers.

    Solitary bees produce males, usually throughout the nesting season. How many and what size of males depends on the species and resources available. It might be worthwhile to do a blog post on production/allocation of males in ants and bees.

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  5. Good find! Try to put it back the way it was and get them to return next year!

    What kind of wood were your boards, how were they spaced, how weathered was the wood, and were they in a damp environment?

  6. Roberta

    Post author

    I would say the boards were both very weathered and damp. They were either very close to the ground or on the ground. I don't know what kind of wood.

  7. Fascinating! I'm so pleased that you found all of those life cycle stages in one place at one time. And to top it off, the pictures are great. Thanks for this post.

  8. Roberta

    Post author


    That is a good question. The adult sweat bees fly to flowers to feed on nectar and gather pollen. The females build nests, usually in the soil. They will spend much of their time constructing and provisioning the nest and the rest gathering food.

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