Ceratina 
Small Carpenter Bees

In Minnesota, there are four described species within the genus Ceratina. These relatively hairless, tiny metallic-blue bees are 2 to 9 mm in length (0.08 to 0.35") and are on the wing from early spring to late autumn. All four species nest in pithy perennial or woody plant stems and have eusocial nests. Each female initiates a nest by herself in a plant stem or pithy wood branch. The female remains alive while the larvae develop in the nest, pupate, then become adults. For some species, the offspring emerge as adults the same growing season, may help rear more offspring, then overwinter in other stems than their nest. The female interacts with her offspring and provides some limited parental care. Prior to offspring emergence the following growing season, the female guards the nest, perching at the end of the cavity over the winter. Mating occurs in spring.

Like other bees in the family Apidae, Ceratina have a very long glossa (tongue) that allows them to access nectaries from tubular or more complexly-shaped flowers. Ceratina are commonly found in yards and gardens and are polylectic, visiting a wide variety of flowers belonging to many plant families and genera.