Sunday 3 September 2017

Snail shell bees

Another little excerpt from my book.

It’s raining. This means my planned excursion to Salisbury Plain to search for the snail shell bee Osmia spinulosa would most likely be quite fruitless, so I’ve decided to stay at home and write about her instead....

I first came across this little solitary bee a few years ago whilst living in West Malvern, Worcestershire. By that time I had begun to take photographs of pretty much anything ant-sized and upwards that visited my tiny patio garden on the side of the hill - and had already uploaded a few thousand images of two, four, six and eight legged creatures to a file on my lap-top titled ‘unidentified garden visitors’. Many of my garden visitors will remain forever unlabelled in that file, but when I enlarged the photograph I took of this particular bee, I could tell from her ‘jizz’ that she must be an Osmia species... and was quite excited when I realised she wasn’t one I already knew. She was certainly not one of my regular bee hotel nesters. 

As well as being excited by the possibility of adding a new bee to my garden tick list, I was also struck by the fact that my hitherto almost-non-existent ID skills had just notched up a level; i.e. I was able to place this bee into a ‘genus’ before going the BWARS (Bees, wasps & ants recording society) site rather than after hours of trawling through it searching for a visual match or posting my photograph on twitter to ask for help. I cannot tell you how empowering this felt.

Once I had decided she was an Osmia species, it was relatively easy to pin-point exactly which. Many of our solitary bee species are impossible to tell apart without a microscope, but this one had unusual blue/green/ eyes so I was able to identify her very quickly.

So, not only was this a new bee (for me) but I had also managed to identify her accurately and entirely by myself as O. spinulosa - the Spined Mason-bee. On their own, these two happenings were already worthy of celebration, but once I started to read about her nesting behaviour I could barely contain my excitement.  I’d been watching other Osmia species flying back and forth to my bee hotels carrying balls of mud or chewed up leaf mastic with their mouthparts - or with the undersides of their abdomens caked in bright yellow/orange pollen - and was already entranced by their nesting behaviour. But this bee doesn't lay her eggs in bee hotels, she lays them in old snail shells. A bee who makes her nest in snail shells… how exciting is that? And how in the world had I never come across her before?!

More about these, and other snail shell nesting bees in my book, but for anyone who has come to this blog searching for information about snail shell bees, please see Steven Falk's amazing flickr pages which are full of photographs and information....

Osmia spinulosa (Spined mason bee)

Osmia bicolor (Red tailed mason bee)

Osmia aurulenta (Gold-fringed mason bee)

B x


  1. What a lovely post. Thank you and congratulations on you superb ID skills! Can I please ask ... I have a couple of insect hotels but only one has ever had anything in it (and I'm not sure where it is now I think of it, I was shoved in the leylandii hedge!) Where is the best place to put them? Our sunny spots positively bake in the summer but the shady spots are damp and horrible in the winter! Same goes for bird next boxes really. While there is loads of info on making these things, there is little about where to put them! (That or my searching skills are rubbish ��)
    Thank you

    1. Here you go.... loads of great information here!