I is for Ichneumon

14 Sunday Dec 2025

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British wasps, ichneumon, Ichneumon wasps, British ichneumons, Pimpla species, Campopleginae pupa, Ichneumon pupa

This has been a good year for sightings of Ichneumon wasps, and I have written a couple of posts about some I’ve found: Three Ichneumon wasps, on 19 August, featured my first Ctenichneumon panzeri record (now verified); Heteropelma amictum, found on the same day but not yet verified (the national Ichneumon recorder is currently working his way through what must be a huge number of national records – these voluntary verifiers do an incredible job!); and Ichneumon stramentor, a species I’d seen previously and which has been verified. Another first sighting, the handsome Tromatobia lineatoria, whose identity has also now been confirmed, featured in a second blog, Ichneumon: Tromatobia lineatoria, published recently, on 13 November.

There have, of course, been other Ichneumon sightings. One that I didn’t write about because I was rather unsure of its identification is shown above; it has now been verified as one of the Pimpla species. And in July I found a cocoon, which I recognised as having been created by an Ichneumon wasp but has now been confirmed as belonging to the subfamily Campopleginae. I’m hoping my luck at finding new Ichneumon species will continue in 2026.

Ichneumon: Tromatobia lineatoria

13 Thursday Nov 2025

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British ichneumons, ichneumon, Ichneumon wasps, parasitic wasp, parasitoid of spider egg sacs, Tromatobia lineatoria

Different days, different ways, different directions …
I have no real plan for my daily walks but, recently, my feet have been taking me past the local park whose railings have turned up some nice insects in the past, and the location is again proving productive.

This handsome ichneumon is one of my finds from last week and, though it hasn’t been confirmed (there doesn’t seem to be anyone nationwide verifying ichneumon records, unfortunately), I think this is Tromatobia lineatoria. There is another very similar looking ichneumon, Perithous scurra, but the female of that species has a much longer ovipositor.

I was a little surprised to find an ichneumon this late in the year but the Naturespot website says this species can be found between May and November, so this is right at the end of its date range. The website entry also says this ichneumon is a parasitoid of spider egg sacs; there are plenty of spider webs strung along the railings so my sighting in this location is understandable.

Three Ichneumon wasps

19 Tuesday Aug 2025

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British ichneumons, British wasps, Ctenicheumon panzeri, Heteropelma amictum, Ichneumon wasps, Ichneumon xanthorius

Two things:
Firstly, my records of these three Ichneumon wasps have not yet been verified so, although I’m fairly confident of their identification, I’m not 100% certain.
And, secondly, I decided to write this blog after someone replied to one of my social media posts, saying – supposedly jokingly – that they had scurried away after seeing one of these creatures, a female with a prominent ‘stinger’ (the implication being that they were frightened of the wasp). So, just to be clear, these wasps will not harm humans; the ‘stinger’ is an ovipositor, for depositing eggs in to their hosts; and many Ichneumon wasps are large, colourful, and really quite beautiful creatures.

At 10-15mm, Ctenichneumon panzeri is a medium-sized Ichneumon that can often be found on umbellifer flowers, as you can see in my photo. As with all Ichneumon wasps, they are parasitoids; Ctenicheumon panzeri deposits its eggs in the larvae of moths of the Noctuidae family.

Heteropelma amictum is one of the larger (20-30mm) and more spectacular ichneumonids, with a long narrow body and equally long back legs, both of which are very prominent when it flies (my flight photo is blurry but I wanted to show you how it holds its body erect and dangles its legs below). Heteropelma amictum uses moth pupae, rather than larvae, as its larval hosts.

Ichneumon xanthorius is another medium-sized wasp, and one I see more often than other species, when it’s feeding on umbellifer flowers or perching on shrubs and bushes. Its larvae feed on the pupae of both moths and butterflies.

The British Natural History Museum has produced an excellent Beginner’s Guide to identifying British ichneumonids, which you can access and download by clicking on this link.

I is for Ichneumon

14 Saturday Dec 2024

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ichneumon, ichneumon wasp pupa, Ichneumon wasps, Ischnus inquisitorius, wasp pupa, wasps

I might not have seen many adult Ichneumon wasps this year but I was fascinated by the discovery of my first ever wasp pupa (An Ichneumon wasp pupa, 13 July).

241214 i is for ichneumon

And I’ve only very recently had verification that I did manage to spot one new Ichneumon species back in April this year. This is a female Ischnus inquisitorius, a wasp I’m having difficulty finding much information about. The Nature Conservation Imaging website reports that it’s ‘an ectoparasitoid of tortricid [a family of moths] pupae’ and the Wild Bristol website says it prefers well-vegetated areas like gardens and allotments, parks and cemeteries, presumably because these are the places where Tortricid moth larvae feed and pupate.

241214 i is for ichneumon Ischnus inquisitorius

An Ichneumon wasp pupa

13 Saturday Jul 2024

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ichneumon wasp pupa, Ichneumon wasps, parasitic wasps, wasp pupa

I was standing in front of a tall patch of nettles, moving from side to side, searching intently through the plant stems, hoping to find the chrysalis of one of the fat Peacock butterfly caterpillars I’d seen munching here just a few days previously (didn’t) when I spotted this black-and-white ‘thing’. It looked almost like a blob of poop but, when I edged cautiously closer (those bl**dy nettles sting!), I could see that it looked a bit furry. At home, some careful googling quickly turned up an identification – it’s the pupa of an Ichneumon wasp, which may well have parasitized one of those lovely fat caterpillars I had been admiring.

I is for ichneumon

14 Thursday Dec 2023

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Amblyjoppa fuscipennis, British ichneumons, British wasps, Ichneumon sarcitorius, Ichneumon wasps, wasp

I’m not very good at photographing and/or identifying bee and wasp species (they’re almost never still, and they can be tricky to identify) so I was very happy to nail not one, but two wasp species in August. Both were ichneumon wasps, the first, which featured in An ichneumon, 10 August, is Amblyjoppa fuscipennis.

231214 Amblyjoppa fuscipennis

And this second beauty was also distinctive enough for me successfully to identify. Meet Ichneumon sarcitorius (from Another ichneumon, 11 August).

231214 Ichneumon sarcitorius

Another ichneumon

11 Friday Aug 2023

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British wasps, ichneumon, Ichneumon sarcitorius, Ichneumon wasps

As I mentioned yesterday, I found two ichneumon wasps on neighbouring umbellifers at Cosmeston last week. Their identities haven’t yet been confirmed but I think I’ve got them right, because their characteristics fit exactly the description in the Natural History Museum’s superb downloadable pdf, Beginner’s guide to identifying British ichneumonids. Today’s wasp is, I believe, a male Ichneumon sarcitorius.

230811 Ichneumon sarcitorius male (1)

The guide lists this ichneumon’s characteristics as follows:

Another of the medium to large (female=10mm, male=14mm) black-and-yellow or black-and-red species. The size, shape and precise colour patterns are distinctive to this species. … The males [which have black-and-yellow banding] are longer with broad white bands across the abdomen at the hind edges of the segments, with conspicuous indentations on the bands of the second and third segments. The bands on the first and fourth segments are usually broken. Both sexes have hind femora tipped with black.
Habitat: usually seen nectaring on umbellifers or flying through foliage hunting

230811 Ichneumon sarcitorius male (2)

An ichneumon

10 Thursday Aug 2023

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Amblyjoppa fuscipennis, British wasps, ichneumon, Ichneumon wasps

I found two ichneumon wasps on neighbouring umbellifers at Cosmeston last week. Their identities haven’t yet been confirmed but I think I’ve got them right, and I’ll explain why in today’s post and tomorrow’s. Firstly, though, I must acknowledge my source for this – the Natural History Museum has an excellent downloadable pdf, Beginner’s guide to identifying British ichneumonids, which I always find very helpful when trying to identify these lovely wasps.

230810 Amblyjoppa fuscipennis fem (1)

Firstly, I believe this is a female Amblyjoppa fuscipennis, which the guide describes as follows:

A large (16–25mm) and beautiful species with a black head. It has a black thorax with a small cream spot and a bright orange abdomen – quite broad and no other colours on it. Can be confused with Protichneumon pisorius, but where P. pisorius has black tips on the hind tibia and tarsus, these features on A. fuscipennis are entirely orange. Flies from June to August.

230810 Amblyjoppa fuscipennis fem (2)