Nematus update

The first willow leaf has now almost been consumed, so the trek to the next leaf will commence very soon. Notice how all of the larvae have migrated to the stalk end of the leaf in preparation for the journey. Larvae are currently about 4-6 mm long.


And here's the bad news as far as the larvae are concerned. This is the primary parasite, a Campodorus sp. Ichneumonid. This is the one that oviposits from under the leaf, curling its long abdomen round the leaf edge. The larvae are currently too small to target, but I suspect egg-laying will commence in a day or two.

Interestingly enough, this specimen was checking out individual leaves and then walking along the willow twig to the next leaf. I suppose it's making sure the trekkers don't escape its attention.

A very common leaf-miner found on Alder is the Sawfly Fenusa dohrnii. This makes a brown blotch mine that wanders between two veins, heading towards the leaf edge.


This close-up of the larva shows the distinctive shape, with wide 'shoulders', which confirms that we are looking at a sawfly rather than a fly, which has simple bullet-shaped larvae.

Moths and leaves

I was up in the deforested heath looking at willows for signs of bud-break and spotted this caterpillar on a bush. Turns out it's the Northern Eggar - Lasiocampa quercus f. callunae. Specimen about 3 cm. long:


This is an interesting species (or species complex). The southern populations feed on Oak and have a one-year lifecycle. Northern and western populations feed on heather and willow and have a two-year lifecycle. Populations in the English midlands vary between one year and two year cycles.

I did find a few willows in bud-break:


And also a single specimen of Alder:


And with catkins:


One of the groups I'll be studying closely this year is leaf-miners. I've previously tended to be a bit cavalier in my leaf-miner hunting, but this year I'm going to be more organised, with target species and timescales all planned in advance.