Solitary Bees

I've been mostly in the garden today and noticed that there was some activity around the bee tubes. 3 solitary bees which I think are leaf cutters were busy in and out of some of the tubes for most of the afternoon.

I've certainly had some success over the years since putting the tubes out and noticed red mason bees as well as these leaf cutters in evidence. Earlier in the year though I was a little concerned to notice a parasite in the form of a small red eyed fly called Cacoxenu indagator around the tubes. In fact I think that several tubes had been suffered parasitism as small holes had appeared in the mud casings and freshly emerged flies were sat around the entrances. There were 6 flies watching the 3 bees going about their business and I must admit that the 6 flies are no more, I'm hoping that they didn't get a chance to lay any eggs in the tubes the bees were working on.

The bees will create upto 6-8 cells, each partitioned from its neighbours with mud or leaves and containing an egg sealed in with enough pollen to see the larva through its growth and development. The larva becomes an adult around mid-September and remains in a cocoon over the winter, biting its way out in the early spring. The bee at the back of the tube is the oldest and is the first to be ready to emerge in late March-early April. It bites through the partition of the cell in front and then bites through the cocoon and nips the rump of the bee inside, waking it from hibernation. This bee then repeats the process until all the bees are awake and ready to exit the nest tube.

You can see a parasitic fly waiting in the tube in the top right of the picture.