Solitary Bees

On the subject of solitary bee parasites I just wanted to share some of my experience through some pictures I took; of some of the mites that I found in my paper tubes and Cacoxenus indagator a fly parasite, so you get to see what they look like up close. Writing this was inspired by seeing the videos of disinfecting solitary bee cocoons.

When I first saw evidence of mites in my plastic tube bee observation box in June 2008, I didn’t know what had happened. Successful cells normally showed the silhouettes of an oval cocoon (vaguely visible in image with labels #4 & 5), however the cell containing mites looked to me as if a developing bee inside it had sneezed (as if having a bizarre hayfever) which had spread the pollen onto the walls of the tube. Hope you can see what I mean in the first picture (labelled #3)

On peeling open my paper tubes at the end of last year I got a real close-up of them. I would need to film this with a macro-video camera, but it was kind of spooky the way something invisible was slithering/crawling in amongst the digested/sneezed pollen dust. In this second image we see this ‘dust’ very clearly (labelled A).

What you may also notice in the middle of this image are the three larvae. These are from Cacoxenus indagator fly which I saw many times at the entrances to my tubes and tunnels. They look like fruit flies, and I have to say that I wasn’t very charitable to them.

Here’s a picture of two of them that I had photographed quite unwittingly in 2007 before I really knew what they were. The red-eyed little devils were apparently conversing amongst themselves, clearly pretending they were up to nothing sinister.

I would guess that about nearly ten percent of my tunnels were infected with their larvae when I open up the tubes at the end of last year. So I cleaned them out manually to ensure a minimum amount of infection this year.

Finding their presence in such quantities underlined the fact to me that I should not leave any tunnels with them in (if I really want to maximise my population’s potential), nor should I put drilled bee blocks in place without paper inserts that I can remove at the end of the season. I have decided that any reeds and tunnels that I have bee unable to disinfect (because I was afraid of damaging the cocoons), will be placed in a different part of the garden.

Here’s a video I took last year on my YouTube channel where we actually get a brief glimpse of a pesky fly snooping around (@40 secs hovering bottom right).

…and finally an even more interesting moment, this last video where we see a solitary bee female doing some spring cleaning of a tunnel of my bee observation box. It wasn’t till afterwards that I realised that I had recorded her tugging out an old empty cocoon (@35s & 48 seconds) and returning to the same tube. Oh yes, and there’s also another pesky Cacoxenus indagator glimpsed at the bottom of the shot hovering just underneath the box @30s.