Small, Colorful and Thirsty: Sweat Bees

The dog days of August have temperatures and rain which are supporting late summer flowering in both the landscapes and wild areas of panhandle Florida. Native wildflowers and many other late bloomers which surround homes and businesses are on full display.

The wet summer conditions have also stimulated the insect population. They, as a general rule, are not nearly as colorful as the flowering plants.

Some butterflies and moths aside, one six-legged native bug stands out for its metallic interpretation of a candy apple green finish. These pollinators with panache are sweat bees.

Also known as Halictid bees, they can vary greatly in appearance. The majority of them are dull to metallic black, with the remaining species being metallic green, or the much less common blue or purple.

Adult sweat bees are frequently seen on blooms when not pursuing a perspiring gardener. Nectar is a major source of food for these mature insects, but they also have a need for the salt in human perspiration.

Halictid bees are found worldwide, but they are especially abundant in temperate regions. In Florida there are 44 species found within eight genera of this family of pollinators

While these bees do not sweat, they are attracted to human perspiration which can be disconcerting when the behavior is initially encountered. These non-aggressive insects use the salt from the sweat for their nutritional needs.

Sweat bees are very important pollinators for many wildflowers and crops, including stone fruits, pears, loquats and field crops. This native bee’s population is also supported by wildflower plantings and by providing nesting areas.

Halictids typically nest in bare soil located in a sunny location. Minimum use of insecticides and ground disturbances will help to increase populations of Halictidae and other native soil nesting bees.

Most halictids nest underground, however nests which are built in rotting wood usually resemble nests located in the soil. Nest architecture of sweat bees in rotting rood is erratic because of the timber’s irregular configuration.

Cells containing an egg or larva usually are lined with a waxy substance extruded from glands on the underside of the bee’s abdomen. These bees help speed the decay and decomposition of deadfall trunks and large branches.

Halictids in north Florida overwinter as mated adult females. In the spring or summer, the females emerge, mate if they have not already done so, and begin digging nests and provisioning cells with pollen and nectar.

In each cell they lay a single egg. When the larva emerges from the egg, it consumes the pollen provision until gone so they must become self-sufficient and locate a suitable food source.

Adult males usually resemble females of the same species, except the guys are often slenderer. The boy sweat bees do not have an area of long dense hairs on their hind legs used for carrying pollen and sometimes have a yellow spot below the antennae on their face.

These flashy flyers add to late summer’s colorful landscape for those who are hardy enough to endure the heat and humidity.

About the author
Les Harrison

Les Harrison is a longtime resident of north Florida, having attended public schools in three counties. He has a Bachelor Degree from the University of Florida in Journalism and a Master’s of Science from Auburn University in Agricultural Economics. He is the author of more than 2000 newspaper and magazine stories and journal articles. During his career, he held positions in private, government and educational (university level) sectors. He holds the title of Extension Agent Emeritus. He can be reached at harrison.gl@gmail.com.

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