A summer with the leafcutters

I’m happy to report that this year there have been up to three leafcutters at any one time nesting in the bee houses, which is a huge improvement on the situation last year where no bees nested at all! I think it likely that this is down to having moved the bee houses to a better location on a little wall at the end of the decking outside my studio.

This summer I have taken thousands of photographs of the leafcutters as well as other solitary bees and bumble bees, and have been busy tagging, editing and organising them all. I now have a good selection of shots of the bees involved in all sort of activities. Over the coming months I’ll be working on drawings from these, which will eventually be used to illustrate the book on the leafcutters. I’ll post progress on the drawings as I complete them, and write in more detail about the bees and what I’ve observed over the summer. But to begin with, here is a selection of photographs to illustrate the story of the leafcutters this year.

The site of the nests, and some old cells:

Above: The last time we saw the leafcutters, the first of the bees was searching for a suitable nest site and clearing out old leaf debris from one of the bamboo stems. Above left is a shot of the site of the bee houses this year, at the end of the decking on a little wall. Some of the herbs I planted for the bees can be seen to the left of the shot. The chair directly in front of the nests is where I rest my camera when I’m pestering the bees! Centre left:The first leafcutter arrived early in the summer and cleared out some of the old nest material from previous years.

Above right:These two shots are of leaf cells from earlier years. The bees from these nests did not hatch out when the time came, and I dissected the cardboard tubes in which they had been laid to investigate. I’ve included the pictures again here to show the construction of the nests. This is the kind of leaf debris which the bee was clearing from the bamboo stems. You can see how pieces of leaf are used to make individual cells, into each of which is laid a single egg provisioned with nectar and pollen collected from the garden. This year the leafcutters did not use the cardboard tubes, although these were used by smaller bees. The earliest leafcutter first made a nest in the bamboo stalks, and when all those of suitable size were filled she moved on to the bee logs which I had drilled earlier in the year. For information about the types of bee houses I have and how to make and site them in your own garden, see this page.

Rose leaves and the bees:

Far left:this is the kind of thing you may have seen in your garden if you have leafcutters nesting nearby. These bees are particularly fond of roses, and cut these tell-tale elongated and circular holes in the leaves. I don’t particularly mind as they don’t seem to harm the plants too much – much worse things seem to afflict my poor roses! Centre left: if you look closely you can see the bee working away on this leaf. The picture centre rightshows how close were some of the rose leaves to the nest site itself. However, the bees are very particular in choosing their leaves and will sometimes fly quite a distance to gather specific material, even though there are what seem to be perfectly good leaves in the vicinity of the nests. I’ll write more about what I’ve observed of their selection process for nesting material at a later date as it is fascinating. Far right is a view of one of the logs which was used this year. Almost all of the holes in this log were filled by a single bee, who was very patient with my photographing of her. The sequence in which they were filled can be seen from the differing colours of the leaves as they dried over time in the sun.

Cutting the leaves:

Above: These bees have been nesting in my garden for a few years now but until this summer I had never seen any bees cutting leaves. Here is just one series of shots I was lucky enough to get of the bees in action. You can see the way she cuts and rolls the piece, ready to fly back to the nest. These elongated pieces are pressed into the sides of the tubes to form the sides of the cells, while circular pieces of leaf are used to seal the ends.

Back at the nest, she seals a row of cells:

Above left: The bee arrives back at the nest with a piece of leaf. Once there she will work with the leaves, either constructing the sides of the cells, or in sealing the ends. In the two shots above centre we see her manipulating a piece of leaf into place with her jaws before pushing it with her head and nibbling and pressing it with her jaws. She is sealing the end of one of the rows of cells in the drilled log. In the above right picture you can see what a marvellous job she makes of pressing and cutting the leaf pieces into place. She uses many layers of leaves in this final seal, flying to and from the roses to gather each piece. The innermost of these discs are worked hard into place, while towards the outside she sometimes only tacks a few final pieces into place.

Feeding and foraging:

Above:The leafcutters lay a single egg into each leaf cell, and provide their offspring, who will not emerge until next summer, with a mixture of pollen and nectar gathered from flowers. Here is a selection of pictures of leafcutters in the garden this summer. Only the one on the right can I be certain is one of ‘my’ nesting bees, as she returns to the log carrying a load of pollen on the hairs of her abdomen. The other bees I think were visitors to the garden but were not nesting here. Which brings me to the question:

Which kind of leafcutter?

You may remember I ordered a back issue of British Wildlife with an identification guide to the leafcutter species. I am fairly sure I have two species, since there are obvious differences in the colour of the hairs on the underside of the abdomen. I am still undecided which species is which, and will post some closer shots of the bees soon, as some of you experts out there may be able to help with identification.

The bees have not finished work this year yet. I thought they had, since we had a some days of rain and cooler weather. It seemed that summer was over and the bees were gone. But over this past weekend there has been sunshine and I was surprised and happy to see the last of the leafcutters carrying a piece of leaf into the bee log. Yesterday morning she was sunning herself on the shelf in front of the nests. I’m not sure how long they usually work, and I expect it probably depends on the weather. The bee who filled the most tubes and features in the majority of the photographs has definitely gone, but this final bee seems to be very busy still, so let’s hope the sunshine lasts.

Meanwhile, inside the nests I expect that the first of the eggs has hatched and the new generation of bees which will chew their way out of the nests next spring is eating away at the food inside their little cells.

Some further pages of this site which you may find of interest:

| How to build bee houses | Plants for bees | Drawings of bees|

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All images ©Christine Farmer 2009-2012
Please contact me if you wish to use any of the images.

Comments

  1. Judith

    Great mind! I am writing about my leaf cutters too. This is a fabulous article and the pictures are great. I think the larger species is Megachile Willoughbiella and the smaller M. Centuncularis but dont quote me. I think even the experts plump for Megachile species. Aren’t they just the most fascinating things?

  2. Christine Post author

    Hello Judith – thanks for the comment! They are indeed fascinating insects and really get me wondering about all sorts of things, especially how did they develop the method of leaf construction? When did the first leafcutter cut a leaf?

    I’ve popped over to your blog – I love your watercolours and the way you describe your trips out and about. You’ve inspired me to try to update this blog a little more frequently… we shall see!

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