Caddis conundrum.

The caddis (Trichoptera) season is starting to warm up, unlike the weather, and they are beginning to appear in some numbers in and around the light traps. Last week's haul reminded me how hard they are as adults and how easy it is to get them wrong. My excuse, early in the season and I've only seen a few fresh ones.

Back in March I had a couple of very early Grammataulius nigropunctatus, one of the relatively easy ones. But then nothing until now.

There was the usual Stenophylax permistus, the confusion species doesn't occur here so they are relatively straightforward.

Stenophylax permistus, a large very distinctive caddis, a strong pale line dorsally.

Then there were a few of these - 

Limnephilus affinus, I don't see too many of these.

And there were three more of these that generally looked like this. 

Limnephilus affinis.

The genetalia were not examined on any of these as they seemed pretty straightforward, I did check out the possibility of L. griseus for the one with the pale dot near the costa.

And then there was this.

Perhaps I should have been alerted by the small size, the same as the various L. affinis. But after a bit of a pause I reckoned it looked like the commonest species I get here, first one for the year, Limnephilus marmoratus. I had posted on Moth Trap Intruders FBG at first asking what it was and then suggesting L. marmoratus.

 

I can't recall the exact time-line but there were some posts suggesting other species so I took some more photos. It was suggested I take a look at the genitalia site here - http://trichoptera.senckenberg.de/Trichoptera%20fennoscandinavica-aktuell/introduction.htm which I did have listed in my links but had totally forgotten about. The genetalia illustrations in the RES key (Barnard and Ross) are to my mind often confusing, I don't get on with them very well, anyway. A suggestion was made that this animal was another L. affinis. Now, during the latter part of this conversation I was battling with a seriously recalcitrant laptop. Asking for an update and functioning at a slow crawl, at best. Distracting. After a bit of looking at genitalia and comparing I gave up. I'd put the animal on iRecord as Limnephilus marmoratus anyway.

This morning I had a look in the test copy of a new book that will be published shortly, about identifying adult caddis. Pale L. affinis can look quite a bit like L. marmoratus, ah! And in the meantime one of the correspondents on Moth Trap Intruders had consulted another expert (SF who has helped me with these things a fair bit in the past, and an author of the afore mentioned book). SF determined Limnephilus affinis. 

I then had a look at all the genetalia and produced the image below - my image plus several from http://trichoptera.senckenberg.de which I probably shouldn't reproduce here but I'm hoping they won't mind.

I think the image also confirms the identification as  L.affinis. 

So many thanks to all involved in this wrestle with caddis adults and a useful outcome. I'll now put images in the Flickr collection for future reference, part of the reason for this post is to prevent the same mistake again... but I wouldn't be surprised, too many things to remember. I'll go and identify a beetle now, I think.

On the birding front a Cuckoo over the house yesterday evening and another dead Bonxie (see update to previous post).

On the beetle front, at Yesnaby today, we walked south, turned over a stone and three Otiorhynchus arcticus, very nice.