Deserving of a bigger buzz

Solitary bees are often ignored in favour of their honey-producing brethren, but their incredible importance as pollinators cannot be overestimated

- DAVID TOMLINSON

WE ALL know honeybees, and the majority of us are equally familiar with bumblebees, even if we struggle to name them individually, but solitary bees? They are a huge group that most of us know little about, but of the 270 species of bee found in Britain, nearly 250 of them are what are known as solitary bees. If that sounds a lot, some 20,000 bee species have been described worldwide, and there are surely many more yet to be named. For the record, there are 24 species of bumblebees to be found in these isles, along with the single species of honeybee.

Few of the solitary bees have English names, while specific identification is usually a challenge even for experts. A small number are easy to name but for most a microscope is needed: the submarginal cells on the forewing are of great value in specific identification, as is the form of the tongue. It’s a highly complicated business and explains why so few have anything other than a scientific name.

Solitary bees are aptly named, as they don’t live in colonies like honeybees or most bumblebees. None use hives, while more than half of them nest in the ground, where they excavate their own chamber. However, the solitary bees are a remarkably diverse and varied lot, so quite a number of them play by a different set of rules. Some build so-called ‘aerial nests’, typically taking over old beetle holes in vegetation. We also have one species of solitary bee, a small metallic-blue insect called Ceratina cyanea, that excavates its own aerial nest, usually in bramble stems. It digs out the pith of the stem to create the space to lay its eggs. There is also a trio of snail-shell-nesting bees, using empty shells for their nests – a remarkably sensible arrangement.