Sweat Bees

Entomologists have described about 20,000 species of bees. Bees are related to wasps. However, unlike most wasps that feed on other insects, bees get most of their protein by collecting pollen. Since pollen is such an important component of the bee diet, bees are consistent and reliable visitors to flowers. The consistency makes bees ideal carriers of pollen from one flower to another. Bees make pollination more efficient so bee pollinated plants need to produce less pollen than wind pollinated plants. Part of the greater efficiency in pollination is used to reward the bees for serving as carriers. The mutually beneficial relationship of flowers and bees is a factor in the diversity of both flowering plants and the bee species that pollinate them. Historically, the rapid radiation of bee species from about 110 to 90 million years ago coincides with the rapid evolution of flowering plants.

The Bee family, Halictidae, contains about 2000 species or 10 percent of the total number of bee species. The Halictids are colloquially known as “sweat bees” because of their habit of drinking sweat. Sweat contains salts and other nutrients that bees use to supplement their diet of pollen and nectar.

The Halictid bees are much smaller than the familiar honey bees and can easily escape notice. The small size and rapid movements make photographing these bees and keeping them in focus a challenge. Some of the Halictids have brilliant green or blue metallic colors such as the one featured in this post. The iridescent colors are important in mate recognition.

Honey bees are important pollinators, but they cannot do it all. Some species of plants are rarely visited by honey bees. Other pollinators, such as sweat bees may be their primary pollinator. Even for plants visited by honey bees, other bee species can increase the level of pollination. Halictids and other bees have an important role as pollinators of crop plants.

Halictid bee with metallic coloration collects pollen and nectar

About jjneal

Jonathan Neal is an Associate Professor of Entomology at Purdue University and author of the textbook, Living With Insects (2010). This blog is a forum to communicate about the intersection of insects with people and policy. This is a personal blog. The opinions and materials posted here are those of the author and are in no way connected with those of my employer.
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5 Responses to Sweat Bees

  1. Anonymous says:

    For some reason I was thinking it said sweet bees, so I thought I’d be reading about honey bees, then I realized you meant “sweat” and laughed at myself.
    This was rather informative. I’ve never heard of this type of bee. I believe I’ve seen them, but when I did it looked like a mutant fly. I learned something new today :).

  2. Addison W. says:

    This was a very informative article. I had no idea that this type of bee existed. I am one of that many that thought most pollination was done by honey bees alone. It is interesting that these sweat bees feed on sweat. Now that I think of it, I remember bees like these landing on my sweaty arm during the summer while I was playing basketball. These bees are incredible how they pollinate so many plants and flowers. Without these sweat bees, there would be a lot less flora in this world.

  3. Anonymous says:

    I remember dealing with sweat bees a lot during summer marching band camps and practices. I wonder, are the bees attracted to a certain amount of sodium (or other minerals) in one’s sweat? From my observations, the bees seemed to like some people more than others, and I don’t believe it has anything to do with the colors of clothing. Or does it? I’ve always been curious.

    • jjneal says:

      Sometimes insects prefer a location rather than a person. Odors and perfumes can be attractive. Bees can see UV light and are commonly attracted to UV colors. On hot dry days, animal sweat is a convenient source of moisture.

  4. Kasey Fell says:

    I remember when I was little and played soccer, I would always come encounter with these little sweat bees. I would always be able to tell that it was a sweat bee because of how much smaller they were compared to normal bees. I would have never been able to guess that these little guys play just as much as an important role in pollination as regular honey bees do.

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