Solitary Bees

I empathise with solitary bees. When we think bee I guess we tend to think of honey bees – the one species of truly social bee we have. They chat to each other and work in groups. They work to the greater good and share their tasks. It’s difficult not to think they derive some form of pleasure or satisfaction from their relationships with each other.
Bumblebees – technically “eusocial” – also belong to their own family in a nest. The queens are obvious and attractive and her sisters are “the sound of summer”. Everyone loves bumblebees.
Solitary bee emergingBut at this time of year, while honey bees and bumblebees are beginning to buzz around the garden in larger numbers, their overlooked cousins are starting to appear. The solitary bees are emerging.
Which type of bee is most “important” to us in its role as a pollinator is a moot point, but it seems sensible to think it’s these guys. For a start, there are well over 200 species in the UK – that’s a lot of different bees adapted to pollinate a lot of different plants.
They live everywhere; in holes in the ground, in walls, roofs, cliffs, and plant stems – I even have them in my bee hives, rather weirdly. It’s easy to persuade some of them to nest in an artificial bee box, unlike bumblebees. These are one piece of paraphenalia produced by the wildlife industry which work pretty well. You can even buy them with viewing windows in the side. If you wanted to make sure you had the optimum design you could even solitary bee houses.
There’s something rather plaintive about solitary bees. Their lives are brief and single minded and they go about them quietly, unnoticed and unheralded. Like so much of what’s living in our back gardens, unless we looked for them we wouldn’t know they were there.
Solitary bee boxLike other bees, all the males do is mate and generally lead a sybaritic existence. They are the first to emerge from the row of eggs carefully laid and provisioned the previous year, and hang around waiting for the females to appear.
The eggs inside the nest hatch and the larvae eat their food before making a cocoon and entering their pupal stage, which is how they overwinter – on their own, imprisoned in the dark for a year. The moment when they emerge is really magical. I saw one break the protective seal at the end of its tube in one of my bee boxes this morning. After a poo and a brief stretch in the sun he spent the next half hour loitering around the box waiting for a female to follow.
Solitary beeThe more common species are mason bees (like this one) and leaf cutter bees, Osmia and Megachile. The female bee finds a good spot to lay their eggs, and provision the end or bottom of the crevice/tube/hole/stem/etc. with a food bed made from pollen. She then lays an egg, and protects it by immuring it with a stopper of mud or leaves, making a cell. This is not a guarantee of safety; solitary bees have their own parasites and predators. She then repeats the operation. When she gets to the top of the nest she might leave at least one cell empty, to persuade woodpeckers et al there’s no-one at home. This often fails.
Her work rate is phenomenal. She is constantly to and fro, looking for nest sites or gathering pollen, mud or leaves, which she works assiduously to protect her offspring. And then, after around a month, she dies.