Dr Douglas Fraser
The last four, frantic weeks of bumble bee activity has calmed. The ground is peppered with carcasses of drones, which until last week were still jumping on queens as they emerged from the many holes in our flat-roof facia boards. Famously, bumble bees are said to defy the physics of flight, but somehow they do, until, that is, a drone latches onto the back of the rather bigger queen. The pair often falls to the ground with an audible thud. Then they co-ordinate their talents to confound Newton’s laws, once more. Presumably, having done their business, the matriarchal society has decided that their continuance is as useful as is the bicycle for fish. There’s a lesson for us all.
Now the queens are flying less (presumably laying eggs more) and the familiar feeding grounds are full of the relatively smaller workers. Currently they are gorging on nectar from geraniums (especially the blue ones) and Cotoneaster.
The Cotoneaster is in full flower and is seething with bees. Rather like when watching faint stars, it is better to look slightly off and see the glimmer with your peripheral vision, it is not quite possible to see all the bees except as a shimmer across your whole field of view. It certainly does not work in a still photograph.
The most common bee in our garden is the tree bumble bee (Bombus hypnorum). This is a newcomer, having apparently crossed the Channel and was first seen in the UK in 1981. It is pretty common across the UK, now. If it is any measure of familiarity, it is this bee that is enjoying the blue Allium flower in the BBC Gardeners’ World opening sequence. It has pale-rusty brown hairs all over its thorax and a white tail (last few segments of the abdomen). In our population, the queens can be as large as 20 mm, whilst the workers are up to 15 mm. This makes it quite a large bee.
Here is an older tree bumble bee worker. Her thorax hairs are wearing off, giving a tonsure, showing her shiny black exoskeleton.
By contrast, the smaller red-tailed bumble bee (Bombus lapidarius) workers are only about 9 or 10 mm, although this year’s queens did measure around 15 – 18 mm in length. The drones are all black.
Highlighting my poor photography skills (for such fast fliers in blinding sunshine), here is the only evidence I captured of the buff-tailed bumble bee (Bombus pratorum). After the tree bumble and the red-tailed bumble, these are the next most common in our garden, but most of my photographs are of Cotoneaster flowers, 1/10th of a second after a bee had left! It is a dreadful photo, but as a field sketch portrait, it works better! On this queen, it is clear to see the single orangey-yellow ‘stole’, a band of yellow at the front of the thorax, +or- a smaller yellow band on the abdomen, and the orangey-buff final segments of the abdomen. Workers have a yellow ‘stole’, whiter tail, with only a hint of buff.
The least common bee this week has been the white-tailed bumble bee (Bombus leucorum), which is the classic picture-book stripy bee. Here a fuzzy shot shows the two yellow bands (one on front of thorax and one about one third of the way down the abdomen) and the pure white abdominal tip. The queens have been as large as 25 mm and the workers up to 18 mm. The drone is about the same size as a worker, but has a yellow face and no pollen on his legs.
There are also honey bees (Apis melifera), which I suspect are totally wild, as I know of no hives within a couple of miles (the usual range).
Now the Cotoneaster flowers are becoming berries (bird food) and the worker bees have moved on to other sources of nectar and pollen. The necessary succession of sources has to be planned and enabled in human-dominated environments. Thankfully, most keen gardeners like flowers for as long as possible. Bees require simple flowers, with easy access to the nectaries and anthers – not always possible in “over-engineered” cultivars. But that is a subject for another virtual field trip, soon.