Nematus pavidus

Those of you who have been following my exploits will know that I have been following the larval stages of the Sawfly Nematus pavidus for a few years.

To summarise very briefly, the larvae appear around this time of year in large batches, and consume vast swathes of Willow leaves, defoliating entire branches. During that time they are visited by parasites and predators of all kinds, with secondary parasitisation taking place. I tend to follow the life-cycle very closely, and keep a photographic record of what I see, so today is day 1 of that process for 2009.

The eggs are laid in batches on the underside of the leaf:

You can clearly see the single ocellus (eye cell) of the larva inside the egg, which is about 1mm long.

The larvae hatch out and spread over the surface of a single leaf:

Notice the characteristic s-shape of the larvae, which are about 2mm. long at the end of day 1.

When I took the shots, I had no idea that surprise number one was already waiting for me. When I got the pictures onto the computer, I spotted this truly minute (1 mm!) parasitoid exploring the larvae:

Based on size and shape, I'd venture that this is one of the Chalcids (parasitic wasps, related to Ichneumonids). So already we have something new for this increasingly interesting project.

The orange spots are a fungal rust.

While I was taking the shots of the larvae, I spotted this Chironomid (non-biting midge) wandering over the leaves:

Every day is different

I went to our highest local point in the expectation of finding some orchids in flower. The first thing I saw was this female Orange Tip - the first I've seen this year, although I've seen the eggs and now the larvae...see below.


The Northern March Orchids were in perfect condition for a photograph. Plenty of specimens in the usual place.


My first thought for this (from distance) was a slightly early Common Spotted Orchid, but the flower shape is identical to the Northern Marsh. This specimen was about 1 metre from the Northern Marsh, so I'm happy to call it the hybrid between the two. Nice portrait.


This Heath Milkwort was a bit of a surprise: I usually find it in deep blue, strong pink or pure white. This pale blue one is entirely new. Wonderful colour.


The first Orange Tip larvae have hatched. This one is about 3mm long...just visible on the stalk of the seedpod.

These are the eggs of the Dock Leaf Beetle, Gastrophysa viridula. The shot was on a Sorrel leaf, which is slightly unusual, although not unknown.


A Willowherb that doesn't look like a Willowherb: New Zealand Willowherb. This seems to like slightly higher places.