There are bees everywhere at the farm vegetable garden just now and in larger numbers than last year. Last week I found the eggs of leaf-cutter bees, but now other species are turning up. The nest of wild honey bees (Apis mellifera) in the wall of a cottage next to the garden, that I watched last year, seems to have grown. The two photographs below were taken exactly a year apart and show the difference in bee numbers. Although the bees have been using that spot for many years, I’ve never seen so many around the entrance. It is a heartening sight.
April 23rd 2011
April 23rd 2010
In the garden itself, we are regularly annoyed by the activities of voles. I haven't seen them, so don’t know if they are field voles or banks voles, but they dig networks of tunnels under the beds. Plants that were previously thriving suddenly wilt and die and, when we investigate, we find there is a big hole under the dry and dangling root, with a little passageway leading into the ground. Voles are part of the food chain, of course, and many will be taken by grass snakes, owls or foxes, but it’s still upsetting to discover that your carrot bed has been undermined by a major excavation.
This time, however, it may well be the turn of the voles to be vexed, for two of their tunnels have been taken over by red mason bees (Osmia rufa). Ha, take that, voles! Red mason bees are solitary, but gregarious, meaning that they will nest close to one another, but each female makes her own nest tube rather than working for a queen. They are incredibly useful in the garden, pollinating a wide variety of plants, especially fruit, so although the holes they’ve chosen for nests are in the carrot bed, we’ll let them stay where they are and sow more carrots somewhere else. It will be interesting to see how the fruit plants at the garden produce this year.
Like the leaf-cutter bees, red mason bees lay eggs in a nest tube, with each egg cell being supplied with pollen and nectar for the emerging bee larva. The main difference is that whilst leaf-cutter bees make their egg cells from rolled leaves, red mason bees build theirs out of mud, hence the name ‘mason bee’. They don’t actually dig into walls, soil or wood, but use existing holes, so they don’t cause any damage. The other pleasing thing about them is that they are not at all aggressive and have a tiny sting, which they will only use if roughly handled, so they are safe for children to observe.
You can encourage mason bees by leaving bundles of hollow plant stems in sheltered spots in the garden and by having a log pile - beetles will bore into the dead wood and then the bees will use the tunnels after the beetles have left.