60 foot blog: Anatomy of a wasp.....

We moored a short distance above Cholmondeston Lock on the Middlewich Branch of the Shropshire Union Canal in Cheshire. Whilst cleaning the windows, I spotted what I thought was a fly on the hatch door. I caught it in my pot, took some photos & then spent most of the day trying to figure out what it was!

I'm really a beginner when it comes to insect anatomy, however it didn't take too long flicking through my insect guide to decide that it was probably some sort of Ichneumons wasp, a large group of parasitic wasps whose larvae live in or on the young stages of other insects. It most closely resembled the picture of a male Amblyteles armatorius, although mine had a more stripey abdomen.

According to the book, wasps from this family should have a thick edge to the forewing and a prominent stigma, which this one seemed to have:

Forewing showing thickened edge & stigma

Amblyteles armatorius should have a yellow or cream scutellum i.e the large plate at the rear of the thorax, and a 'hind yellow trochanter', the trochanter being the segment of the leg between the large femur & the small coxa, which attaches the leg to the thorax. It clearly has a yellow scutellum, and as far as I can make out the trochanter on the hind leg is yellow.

Yellow scutellum & yellow hind trochanter

I then spent ages looking on the web to see if I could find anything closer to this wasp & discovered a website which had a photo of a female Amblyteles armatorius which looks just like this. So as long as that was correctly identified, then that's probably what this is! However, there are apparently several similar species, so I could be wrong!

In common with a lot of other insects, wasps have not only the large compound eyes, but also simple eyes in the middle of their head called ocelli, usually 3 of them arranged in a triangle. It's thought that they can just detect variations in light intensity.