Bee Ecology

Solitary Bee Ecology and Conservation

What are solitary bees?

When most people think of a bee, they imagine a honeybee. In fact, there are around 250 species of bee in the UK, they are a range of sizes and shapes, only a handful of which are striped, and only one of which produces honey! Perhaps most shocking to even the most enthusiastic bee-fancier, is that only around 10% of UK species have any kind of queen, the vast majority live solitary lives. Not being part of a colony doesn’t make these bees any less interesting though!

Types of UK solitary bees

Aerial Nesting (Anthidium, Chelostoma, Heriades)

Aerial or cavity nesting bees are the most likely to visit our nest boxes. These species tend to build their nests in pre-made tunnels, for instance in hollow twigs or holes left behind by wood-boring beetles. The nests are then divided into chambers using mud, leaves or even animal hairs, depending on the species. In each of these chambers, the female lays a single egg next to a ball of pollen that the growing larva will devour as it grows.

anthidium manicatum female

The wool-carder bee (Anthidium manicatum) actually collect plant fibres from plants and use these to build their nests

Photo credit: Steven Falk

 

megachile ligniseca

A male wood-carving leaf-cutter bee (Megachile ligniseca) on the front of a bee hotel in Shrophshire. The females of these species cut out pieces of leaf with their jaws and use them to create their nest-chambers. Although the type of bee hotel is different to the ones we will use, leaf-cutter bees would be welcome visitors to our nest boxes!

Photo credit: Steven Falk

Ground Nesting Bees

Some solitary species take refuge underground, where their young are better protected from predators and the elements. These mining and digging bees can often be found in large aggregations, with numerous nests side-by-side. With so many nests together, some people mistake these aggregations for swarms of bees, but the bees rarely help each other out directly. Rather, by being present in larger numbers they are at an advantage: they look more frightening and confusing to predators, and, if attacked, each bee has a lower probability of being eaten. While we are unlikely to get these sorts of bees in our nest boxes, they are common in garden lawns. Look out for the small ant-hill-type mounds and welcome your visitors as part of the family. In fact, if you are visiting any of our nest boxes in the Oxford Colleges, many of the college quads are home to nesting aggregation of the tawny mining bee (see photo)! 

andrena fulva

The female Tawny Mining Bee (Andrena fulva) is one of our most striking solitary bees. Males, by comparison, are less distinct and often confused for closely related species

Photo credit: Steven Falk

 

colletes hederae

Female ivy bees (Colletes hederae) are found nesting in dense aggregations in sandy areas. As the name suggests, this species feeds primarily on common ivy (Hedera helix) and is one of the latest active bee species, with a flying period from September to as late as November. It is also one of the newest UK species, having first arrived in 2001.

Photo credit: Steven Falk

Snail Nesting Bees

No description of the UK’s solitary bee species would be complete without mention of the red-tailed mason bee (Osmia bicolor) that actually makes its nests in abandoned snail shells. What is even more remarkable, is the female seems to take steps to make the nest inconspicuous, collecting grass stalks and other objects to conceal the nest.

osmia bicolor

The striking female red-tailed mason bee (Osmia bicolor) actually nests in empty snail shells!

Photo credit: Steven Falk

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