A mystery

I was peeling a stem of Soft Rush (as one does) yesterday, and spotted what looked like a caterpillar with an orange head and a green tail inside the pith:

Juncus stem and 'caterpillar'

(For scale, the Juncus rush is about 3mm. in diameter.)

But when I examined 'it' under a lens, I found I had a collection of separate 'things' all lying adjacent to each other:

Juncus stem with 15 separate 'things'

I immediately thought of the micromoth Coleophora alticolella, which feeds on Juncus flowers, and thought that these might be the overwintering eggs, so I fired the picture off to a couple of experts (isn't the internet wonderful?) for their opinion. The consensus is that these aren't micromoth eggs, but the overwintering eonymphs of Juncus-mining sawflies.

I have mentioned before that sawflies have an 'interesting' development lifecycle and these are a prime example of that. Whereas butterflies and moths go through a strict egg-larva-pupa-adult lifecycle, sawflies can exist in a range of states including some intermediate nymph stages like we see here.

Now we notice a few things about the photograph:

1) we have three different colours: orange, white and green (very patriotic, for an Irish specimen)

2) the white ones have a brown dot on them

3) the brown dots appear in different places, but overall they describe a smooth(ish) arc.

Until something emerges (or a range of somethings emerge) from these cocoons, we can only speculate about what we actually have here:

• It could be that the coloured specimens are about to emerge, or that they have failed and are dead.

• The arc of brown dots could be the eyes of the eonymphs, or they could be the eggs of a parasitic wasp.

I have fired the images off to a specialist group who are experts on sawflies and I am currently waiting to see what they have to say. I could separate some of the cocoons and put them under a microscope, but I'm very keen to leave them intact to see what emerges, so I have put the sample into a sealed tube and hope to be able to identify the adults after they emerge.

I have searched the internet and can find no images of the eonymphs of likely species, so this might well be the first image of its kind.

It's only March and already we have mysteries.

Sawflies again

The first batches of Nematus pavidus larvae are almost full size now, so I suppose they'll soon be moving down the branches to overwinter.


The Campodorus females are still lurking, laying eggs when they get a chance, although I haven't seen any of the Mesochorus females for about a week, now. This shot shows full-size larvae with a Campodorus female in the centre of the leaf:



Notice a family resemblance? This is another sawfly larva that I find from time to time on either Bramble or Raspberry. No id, yet.

End of a Sawfly

The other day I showed the Shieldbug Picromerus bidens, which are predatory on caterpillars. This shot shows a sawfly larva being consumed tail-first by another specimen. The larva is about 3 cm. long and is suspended from the proboscis of the Shield Bug.


The original shot is much higher quality, but for some reason (speed?) Blogger always drops the quality of images.

The urge to reproduce

I never cease to be amazed at the attempts of disadvantaged plants to reproduce. This tiny (5 cm. tall) Knapweed had managed to produce viable flowers despite having seeded in the middle of a road.


This Willow had been damaged much earlier in the year, and the new shoot has a catkin on the end of it:


I suppose the urge to make offspring is an essential part of the make-up of any successful species.

This blue Sawfly is quite numerous at the moment. The curved antennae - somewhat reminscent of horns - are quite distinctive.

Bad light

Even when it isn't raining at the moment, any light that we do get is horrible, but we do what we can.

The Angelica is currently covered with insects of all kinds. Most are nectaring, but a few of them use the nectaring insects as a source of their own food in a similar way that crocodiles and lions use watering-holes as prime feeding ground.


The above shot shows:

A) Ichneumonids
B) Tenthredo sp. Sawfly
C) Ectemnius Wasp
D) Tree Wasp

This nectaring Ichneumonid poses a bit of a problem. I've seen this upward-curved ovipositor a few times, but I can't really work out the purpose of that curve. Maybe it reverses into a hole and lays its egg backwards?


Sometimes you see something and you intuitively know it's new. This Leafhopper was a bit larger than the usual ones and slightly more rounded. A quick check through the references reveals that it's Aphrophora alni, and is new to me.


Similarly, this hoverfly shouted "I'm new, too", and I managed to get a few shots before it flew off. It's certainly a Melangyna sp., but that's as close as we can get without capturing it.


These are scarce at the best of times: the larvae are specialist eaters of specific aphids.

Sun!

The view East from Leg 2 of the Hedgerow:



This is by far the smallest local hoverfly - Neoascia podagrica. In order to see them, I have to sit on a verge and wait for tiny shimmering dots to hover into view. This specimen was about 5 mm long. For those of you raised on inches, that's about 1/5th of an inch. Check it out on a ruler.


It took a little while to resolve this pair of Cixiids. These are true bugs - related to the much more common leaf hoppers.


Rhingia campestris is a very visible hoverfly with its rosy abdomen clearly seen in flight. The long 'nose' is a sheath for its extremely long, folding tongue. Previously seen only in rural areas (its larvae live in cow dung), this is now being seen in more urban settings, leading to the assumption that more domesticated dung is also being used.


This male Melanostoma scalare was nectaring on Germander Speedwell and Dog Violets:

Sawflies are closely related to bees and wasps. The female's sting is modified into a saw which is used to cut slits in leaves to hold her eggs.

Further update on Ichneumonids and sawflies

In February, I posted about hyperparasitic Ichneumonids, and yesterday the story took a further amazing twist.

To summarise, the Ichneumonid I had been following was a hyperparasite, which was targetting the larvae of the primary parasite already inside the sawfly larva. Since then I have been searching for the primary parasite to complete the picture.

Yesterday I found a new Ichneumonid ovipositing in the sawfly larvae, but the ovipositing process was the most bizarre I've ever seen. This is a shot taken from below the leaf:


The Ichneumonid is under the leaf, with her abdomen curled round the edge of the leaf and ovipositing into the larva, which is above the leaf. I've seen these long-abdomened wasps before, but didn't know why the abdomen was so long. Now I know.

Just in case there's any doubt, here's the ovipositor in action:

This shot shows the Ichneumonid leaving the scene after her work was done:

The portion of leaf shown is about 8 cm. long.

You couldn't write a story like this.