30-Apr April’s Bee Society: Builders & Bandits

The first thing to do when you see a bee is to make a note of its size, colour, hairiness, whether it has any bands of colour, what habitat you are in and possibly what flowers it is visiting. It is also worth checking whether or not it has pollen baskets. These are hairs on its legs where it collects pollen to feed its young and they are often full of bright orange or yellow pollen. All bees collect nectar and most collect pollen which is why they visit our gardens and flower-rich meadows. However, others prefer open, sandy areas, heaths and even that most curious of habitats, well-trodden paths.

The most familiar of all bees is the honey bee Apis mellifera which is a good place to start as so many other bees are similar with just slight differences. Any queens will not be seen as they are in hives or cavities in trees laying eggs and it is too early to see any drones. The workers, of which there could be several thousand, are generally golden brown with some white hairs, have a definite waist, some faint banding and a slightly pointed roundish tail. Bumble bees or Humble bees as they used to be called are the ones most associated with early spring. They are usually large, very hairy, without a waist and often with distinct bands of colours. They produce workers like honey bees but far less, perhaps just a few hundred. Even so it is all these workers produced by these colonial bees that account for most that we notice as our other bees produce far less offspring. There are in the region of twenty different bumble bees in London but only five or six that you tend to see more commonly. We can now add three more to those already mentioned.

The Brown carder bee Bombus pascuorum is completely ginger-brown with no other banding. Carder bees get their name from the way they use their jaws to “carder” dried moss and grasses to construct their nests which can look like miniature bird nests. A larger red-tailed bumble bee than the one we saw last month could well be B. lapidarius.

It is very black and shiny with a reddish-brown tail. Any almost all-black bee at this time could be the flower bee Anthophora plumipes especially if it seems to have orange legs. It tends to be quicker than other bees that we have seen, buzzes at a higher pitch and as its name suggests hovers around flowers, especially tubular ones in our gardens.

There are over two hundred different solitary bees in Britain and although many are declining a good proportion of them have been recorded on Mitcham Common. They generally lay there eggs singly on a reserve of pollen and honey that they have collected and then deposited down some kind of burrow. They then just leave their offspring to develop. They repeat this process perhaps in the same burrow or several different places and after doing so quite often die.

We tend to notice many of them entering or leaving these tiny holes in sandy banks which are the entrances to their burrows. This behaviour is typical of mining bees e.g. Andrena spp. of which there are over sixty different species on Mitcham Common. They tend to be small bees whose stings in some cases cannot even penetrate our skin. They have, as a rule, hairy thoraxes and less hairy abdomens which vary in colour from red to brown and occasionally are black. If they burrow into lawns they are often referred to as lawn bees. Here they leave small, tell-tale mounds of earth where they have been burrowing and one species that tends to get noticed more than most is the large, hairy fox-red Tawny Mining bee Andrena fulva.

Another group of bees seen more in flower-rich meadows are the Sweat bees (e.g Halictus and Lasioglossum). They tend to be medium-sized brown or black, often with some blue or green metallic colouration. Some are semi-social with several females sharing the same burrow with just one bee acting as guard at the entrance moving to one side to let others in and out. Digger bees also burrow in open ground but are far more like bumble bees. Some construct small pots which they fill with honey and then lay an egg floating on the top. Potter bees do the same. Various other bees are attracted to masonry to rear their families.

The Plasterer bees (Colletes) are one such group noted for their hairy heads. They have no pollen baskets as unusually they carry their nectar in their crops. Sometimes small bubbles of nectar can be seen on their faces. Yellow-faced bees are closely related but tend to be very dark in colour without markings except for distinctive yellow or pale faces and perhaps a few palish bands on their abdomen.

Mason bees (Osmia spp.) also nest in holes in walls as you might expect. Osmia rufa is a ginger-red rather solid-looking bee but others have metallic colours and smoky wings.

A number are attracted to gardens by our “bee hotels” made of sections of bamboo but others are known to nest in key holes, bramble stems and even snail shells. Another group more typical of meadows are the Flower bees. These tend to be stout and easily confused with small bumble bees. Leaf-cutting bees e.g. Megachile spp.) cut neat discs out of rose, lilac and willow leaves. These they then roll up and push down their burrow one after the other, each rolled leaf containing an egg and some food. The female then sometimes sits at the entrance of her burrow biting anything that tries to enter. Leaf-cutters as a group tend to be solid-looking, sometimes with yellow markings and wide heads.

Any bee we see collecting downy material to line its nest from the leaves of mulleins or lamb’s ear Stachys lanata is likely to be a Carder bee. They are often totally brown but do sometimes look greyish or reddish. The Common Carder bee Bombus pascuorum is a smallish bumble bee with a noticeably hairy reddish thorax. It is the only bumble bee in London to have a reddish thorax.

Bees that burrow into old or dead wood were all generally in the past referred to as Carpenter bees. Some pick the old, unused burrows of other creatures and others prefer to excavate their own.

Sometimes small amounts of sawdust near the entrances testify to their activities. Nowadays, the word Carpenter is largely used just to describe Xylocopa species which includes the never-to-be-forgotten gigantic cobalt blue Xylocarpa violacea. Not only is it enormous, shiny and vividly coloured but also noisy and very fast flying. Until recently it was an occasional vagrant from southern Europe but is now making more appearances even in my own garden in central London.

Finally, as if identifying different bees in the field wasn’t difficult enough, there are the Cuckoo or Homeless bees. These are parasitic and like a cuckoo lay their eggs in the nests of other bees. Here they hatch and not only eat the foodstore but occasionally the occupants and even kill the queen. The difficulty in identifying them is that they often visually mimic their hosts although you sometimes do see them near bee nests acting furtively waiting for a chance to nip in and lay an egg. As a general rule they are often darker, less hairy and more shiny than their hosts, although some are very wasp-like e.g. Nomada spp. All of them possess no pollen baskets, obviously having no need for them.