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.