Last week I was seeing these little bees on our woollen breeches, Hydrophyllum appendiculatum, along the old road at Bull Mills. Its distinctive marking and color made it easy to identify as a pure green sweat bee, Augochlora pura, AP for short. It is in the Halictidae family of sweat bees, named because of their habit of landing on our skin, presumably for salt. They are commonly seen in forested areas and in one study accounted for 92% of the bees collected. They are able to sting defensively but I have never been stung except when there was one that I didn't notice on the lid of a soda I was drinking. Even then the lip pain lasted only a few seconds.
For a little bee measuring 1/3 inch there is an incredible amount of information on its life cycle. Females mate in August and September but remain in ovarian diapause over winter before creating new nests and having offspring the next year. All the males die in winter, their only purpose achieved, but during mating they are very aggressive.
"Males fly in swarms and hover over flowers. They fly from flower to flower and feed, and land on any similarly sized insect on a flower. In fact, they even pounce on black dots on paper.[11] When a male finds a receptive female, he mates with her for from three seconds through two minutes. Instead of pursuing females in the air, A. pura males wait for them to land on flowers. Males have been observed to stack themselves on top of a copulating male, attempting to mate with that one female. Augochlora pura males have been observed to stroke the female's head with their antennae before and during copulation." Wikipedia
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| Nest cell with food and larva - Wikipedia |
Although AP has been observed feeding on over 40 species including a few exotics ignored by other bees, my observations have all been on great waterleaf, aka woolen breeches which we discussed in a blog last week.
