Friday, 8 December 2017

Another update!

On 14th September 2014, I posted about a Stigmella perpygmaeella leaf mine on Hawthorn with a hymenopteran parasite in the mine. I couldn't get any further with the identification at the time, so left the wasp identification abstract.

I have now got a little further with the wasp identification, so here's a little update, with an updated version of the image.

The original micromoth larva is shown at point A, and is quite clearly chewed and dead. At point B we have the 'visitor', which has a distinctive dark gut. I have now discovered that the intruder is a Eulophid wasp, which is an ectoparasitoid of the micromoth larva.

So the sequence of events is as follows:

  1. Female micromoth lays her egg on the leaf.
  2. Egg hatches and the larva tunnels through the leaf, getting larger as it feeds, until reaching point A.
  3. Female Eulophid detects the moth larva inside the leaf and deposits her egg on or near the moth larva.
  4. Eulophid egg hatches and the wasp larva consumes the moth larva, leaving just the head capsule and other debris.
  5. Eulophid larva moves off back through the mine where it will pupate at point B.

I wonder if the wasp larva makes its little journey back down the mine in order to avoid being detected by a potential hyperparasitoid.

Anyway, here's the picture:

Eulophid larva (B) having consumed Stigmella perpygmaeella larva (A)

Tuesday, 7 November 2017

Out of the blue

In 2004 I photographed a 'caterpillar' that closely resembled the male flowers of Pine, and I assumed that the larva was gaining some protection from mimicry, since the area was covered in fallen flowers. The original page is here, half way down.
I was subsequently informed that the caterpillar had been parasitised, and that it hadn't originally been that colour, so I binned the assumption about mimicry and moved on with my life.

I have made a composite image of the original images for comparison:

'mummy' (left) and male pine flower (right) for comparison

This morning I was amazed to find a virtually identical image where the parasitoid was identified as an Aleiodes (Braconid) wasp.

The Aleiodes lays an egg in the live moth larva and wraps the parasitised larva in a protective shell which results in the mummified appearance shown above. The Aleiodes larva feeds internally on the mummified caterpillar and pupates internally before emerging as an adult. The lifecycle of these Braconids is fascinating and complex, with some species managing to become bivoltine by parasitising different (and often unrelated) univoltine moth species which have mature larvae at different times of the year.

I suppose the Aleiodes might still gain some protection from mimicry, since there will almost certainly be hyperparasitoid wasps that target the mummies.

So. Still much research to be done, but it's nice to get even a Genus id after 13 years.

Sunday, 9 July 2017

Year end

The last year or so has been spent mostly poring over microscopes and identifying obscure specimens from different parts of Ireland. I also started the Irish Leafmine recording system in conjunction with the National Biodiversty Data Centre, and that initiative has seen a new batch of mine-recorders submitting records for the first time. Here's a shot of the coverage in the first year:

The scheme, which can be accessed here, necessitated the creation of the first Irish checklist of leafminers, which currently stands at 839 species, and can be accessed here.

I have also been working on an Irish checklist of plant galls in an effort to increase awareness and recording of plant galls in Ireland. Hopefully this new scheme will get under way in 2017. This list currently stands at 1277 species (there are many more types of organism that cause galls than those that mine leaves!).

Now that I have more or less retired from my computing career, I have devoted more time to my book, which documents the more interesting finds over the last 14 years since I started taking photographs and writing my blogs. I think 2017 might be the year that I try to find a publisher.