Thursday, July 16, 2009

Leaf-cutter Bee

29th June - I noticed for the first time some activity around my homemade solitary bee nesting box. A Leaf-cutter Bee Megachile centuncularis, has started to build a nest in one of the bamboo cane chambers.
As regular readers of this blog will know, I have had considerable success with my purpose built nest box which is South facing (See Mason Bee blog - April 2008).
The homemade nest box is East facing and uses tatty old bamboo canes cut off to similar lengths as the purpose built one. The Mason Bees do not seem to like this one.

2nd July - The chamber has been completed as can be seen from the green leaf plug at the entrance.

3rd July - A second nest hole is now being worked on.
Whether this is the same female or another one, I cannot be sure. As the dates are so close together I'm assuming it is the same female. Within the bamboo cane the leafcutter bee collects fragments of leaves to construct individual nest cells. Within each cell the bee lays an egg and provides nectar and pollen for the developing larvae. The cell is then sealed with another leaf and the finished cell somewhat resembles a cigar butt.

3rd July - The second nest hole is near completion. The female caps the nest hole with a solid plug made of cemented leaf pieces.

3rd July - The female is just completing the finishing touches. A completed nest tunnel will contain a dozen or more cells in a tube 10cm to 20cm long. My tubes are 15cm long. The adult female can lay between 35 and 40 eggs and live up to 2 months. Therefore, it is even more likely that the same female has so far used two tubes.

4th July - 2 nest holes now completed. Once finished, the female will desert the nest and leave nature to take its course. The eggs hatch into larvae, consume the pollen ball and enter hibernation. The following spring, the larvae pupate and turn into adult bees.

Saturday, July 04, 2009

Nature can seem unkind

21st June.

I found this rather beautiful caterpillar on my Variegated Yellow Loosestrife
Lysimachia punctata 'Alexander'.

My wife Bron, who is very good at identifying caterpillars, tells me this is the larva of the Light Knot Grass moth Acronicta menyanthidis. What confused me was the two white marks on the last two Abdominal Segments.
The foodplants of this moth are Heather, bog myrtle, bilberry, birch, sallow and other plants! Therefore, as this was found on Yellow Loosestrife, then I guess this counts as the 'other plants'.

I have never recorded the Light Knot Grass moth in my garden, therefore I have transferred the caterpillar to my rearing tent, along with some fresh leaves.

27th June.

Alas, as this picture shows, two small white larvae have emerged from the caterpillar, which now appears to be dead.

Perhaps it has been parasitised by Ichneumon wasps, which I do see regularly around the garden.

If anyone has any idea on the species of parasite, then please let me know.