This tiny bee measures just 5mm long and is one of the most under-recorded bees in the UK. For many years this bee was considered to be very rare until scientists realised it’s small size and habit of nesting in bramble thickets meant it was being overlooked and was simply under-recorded.
Females of this species excavate the pithy centres of Bramble and Raspberry stems and use the hollows to form their nests. They are unusual in that they are occasionally primitively social with offspring sometimes remaining in the nest to help their mother provision a second batch of larva. On the continent, their close cousins Ceratina nigrolabiata are the only bees known to help in protecting the offspring by guarding the nest entrance against predators and pollen thieves.
The Small Blue Carpenter Bee - Ceratina cyanea on a Bramble stalk
They are also unusual in that they are one of the few British solitary bees to overwinter as an emerged adult. The mated females overwinter by hibernating inside their hollow bramble stem nests. Most of our other solitary bees die, and only their immature offspring survive until the following year when they emerge as adults.
Look out for these bees with their slow casual flights foraging on Bramble flowers, Ragworts, Cinquefoils, Scabious, and Dandelion-like composite flowers.