Sand Fly Rhyacophila dorsalis - Singles caught in the garden on 25th September and 14th October 2019 and 18th April and 21st June 2020. This is the by far the commonest member of the family in Norfolk.
male Sand Fly Ryacophila dorsalis, North Elmham, 18th April 2020
male Sand Fly Ryacophila dorsalis, North Elmham, 21st June 2020
Rhyacophila fasciata - None. I've never recorded this species but there are a few dots on the map along the Wensum Valley according to the NBN Atlas so there must be a chance I'll find one locally someday.
Rhyacophila munda - This species does not occur in Norfolk but is common in the north and west of Britain. I caught my first at Penberth in Cornwall on 7th October 2020.
male Ryacophila munda, Penberth, 7th October 2020 (showing tip of the abdomen)
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Family GLOSSOSOMATIDAE
Agapetus fuscipes - None. Going on the records in the NBN Atlas this appears to be the only member of this family in Norfolk, but although it appears to be common across the county I'm yet to find one. Maybe they don't come to light readily, or perhaps they don't wander far from water?
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Family HYDROPTILIDAE (the MICRO CADDISFLIES)
I don't always record all of the micro caddis that turn up in my trap as they are quite easy to lose, and on busy nights I don't even make all that much effort to retain all of them as they can be quite time consuming to identify. Having said that, by 2020 I'd got enough experience of them to find them quicker and easier to process. I've found that the abdomens need clearing well in fresh KOH and a high magnification microscope makes it much easier to see the critical details in females (which seem to make up the vast majority in most species). Having said that, conversely over-clearing makes some detail harder to see on one or two species, but with experience and knowing where to look this has become a lot easier.
Hydroptila sparsa - 3 in the garden in June and July 2019 and 8 between 26th May and 20th August 2020. Males have very distinctive genitalia but the majority that I catch (all but one in both years) are female. I don't find it easy to see the shape of the dorsal excision on segment VIII but the internal ventral sclerite is easy enough to find when cleared properly, and I hope I'm right in thinking this is diagnostic. The double dark patch on the antennae has been a consistent feature of this species and seems to be a fairly reliable way of eliminating the other common species that occur here (except Orthotrichia costalis which is distinctive in other ways). However this character was shared by the only other Hydroptila I've caught here so examination of the genitalia remains essential for species ID. I haven't recorded enough of the other species to know if the character is distinctive for the whole genus - maybe so?
female Hydroptila sparsa, North Elmham, 1st June 2019
male Hydroptila sparsa, North Elmham, 23rd July 2019
2 female Hydroptila sparsa, North Elmham, 30th July 2020 - showing the internal ventral sclerite of the first one
male Hydroptila sparsa, North Elmham, 20th August 2020 - showing the genital capsule at different orientations, the aedeagus removed and both together to show scale
Hydroptila tineoides - A female caught in my garden moth trap on 10th August 2020, the first time I've identified this species. The NBN Atlas shows a few records in east Norfolk but none round here, however this genus isn't very well recorded so that probably doesn't mean they're especially rare. Apart from sparsa and tineoides there are several Hydroptila species that could potentially be found here but none of them are commonly recorded in Norfolk.
female Hydroptila tineoides, North Elmham, 10th August 2020 - showing the setose ventral lobes
Ithytrichia lamellaris - A total of 15 in the garden moth trap between 1st June and 2nd September 2019 and 14 between 21st May and 14th September 2020. Also one at the meadows on 25th May 2019. This seems to be one of the two commonest micro caddisflies here. With males the pair of parallel dark internal rods in segment IX are easy enough to see once cleared but may need looking for at different focuses as they may not always immediately obvious. Females seem to be much commoner here (13 of the 14 in 2020) and it can be difficult to find the diagnostic 3-lobed posterior margin on sternite VIII if the abdomen hasn't been cleared sufficiently well. This species seems to show a long dark patch at or very close to the tips of the antennae though this can be faint on some individuals (and the antennae are often broken off below the dark tip).
female Ithytrichia lamellaris, North Elmham Cathedral Meadows, 25th May 2019
male Ithytrichia lamellaris, North Elmham, 1st June 2019 - the pair of rods only really obvious in the second focus
male and female Ithytrichia lamellaris, North Elmham, 25th August 2019
female Ithytrichia lamellaris, North Elmham, 20th July 2020 - showing sternite VIII
female Ithytrichia lamellaris, North Elmham, 14th September 2020
Agraylea multipunctata - None in 2019 or 2020. I have recorded females at home twice (2016 and 2018).
Agraylea sexmaculata - single males caught at home on 25th and 27th August and 24th September 2019. A male and a female caught on 10th August 2020 and another pair the following night. The broad dark-rimmed claspers of the males of this species makes them relatively easily to identify but I have really struggled with some females.
male Agraylea sexmaculata, North Elmham, 25th August 2019
male Agraylea sexmaculata, North Elmham, 27th August 2019
male Agraylea sexmaculata, North Elmham, 24th September 2019
male Agraylea sexmaculata, North Elmham, 10th August 2020 - showing the claspers
A female caddisfly caught at the meadows on 4th August 2019 keyed to Agraylea/Allotrichia but then proved an interesting identification challenge as it was much larger than Agraylea should be (forewing 5.4mm - the book says 2.5-3.5mm for female sexmaculata). With plain grey wings and yellowish abdomen it closely resembled an online photo of Allotrichia pallicornis which should be much closer to this in size (4-5mm), so at first I wondered if it might prove to be this species despite the NBN Atlas not showing any records in East Anglia. Examining the genitalia did not support this conclusion sadly. I find it very difficult to see the subtle tiny details in the abdomen without also damaging them and either rendering the detail unrecognisable or losing it altogether. So it was with this - what I could see seemed to fit sexmaculata better than the other options considered, but I couldn't clearly make out the shape of sternite VIII and the internal aparatus were not really visible at all. A best-fit but less-than-convincing ID as Agraylea sexmaculata was as far as I could go with this.
possible female Agraylea sexmaculata, North Elmham Cathedral Meadows, 4th August 2019
I found a very similar caddisfly in my garden trap in 2020. It was virtually the same size (5.3mm forewing), and clearly keyed to Agraylea/Allotrichia. It was fresher, so with slightly more patterned wings, but the same size, structure and overall colour tones, including the yellowish abdomen. Again, despite taking great care, I had the same problems with the dissection. At one point I thought I might have seen a dark line to one side, that I wondered if it could be the asymetrical groove of pallicornis, but as I cleaned it gently this disappeared - I don't think it was anything. I couldn't find any internal aparatus despite taking as much care as I could not to remove it accidentally. Again I couldn't really make out the shape of sternite VIII. At this point I started to wonder if both of these were in fact not even Hydroptilids, so I returned to the caddisfly and the family key. I don't think I made any errors keying, but I checked to see where I would end up if I followed through having taken the opposite direction at on any one of the couplets. They were all dead ends or clearly wrong results, so I'm fairly happy they were indeed Agraylea, but clearly I need to gain more experience with these.
possible female Agraylea sexmaculata, North Elmham, 23rd June 2020
Orthotrichia costalis - 2 in the garden trap on 24th June and another 2 on 16th July 2019, all females. A better year in 2020 with 12 (1 male, 11 females) between 20th June and 24th August. This is the only member of the genus I've found so far but Orthotrichia angustella may perhaps be possible. I think both species are supposed to show the pale fringes to the wings that easily separates most individuals from the other micro caddisflies I've recorded here, so I always check the genitalia. On females the pair of dark triangular ventral sclerites are distinctive once found but when over-cleared these can be very faint and hard to see. Fresh examples of this species show three dark bands on the antennae though worn examples or those with broken antennae may show only two, like at least some Hydroptila species.
female Orthotrichia costalis, North Elmham, 24th June 2019
2 female Orthotrichia costalis, North Elmham, 16th July 2019
female Orthotrichia costalis, North Elmham, 20th June 2020 - showing the triangular ventral sclerites
male Orthotrichia costalis, North Elmham, 25th June 2020 - showing the genital capsule
female Orthotrichia costalis, North Elmham, 30th June 2020
Tricholeiochiton fagesii - None. There seem to be a few records of this species in Norfolk but I've never come across it.
Oxyethira flavicornis - A total of 17 recorded in the garden between 22nd May and 12th September 2019 and 24 between 26th April and 3rd September 2020. This species peaks in late June to mid July and again in late August/early September. Also one in my parents' garden in Keswick (Cumbria) on 8th June 2019 and one at the meadows on 17th May 2020. On females I don't find it easy to see the lateral margins of the fused segments VIII+IX highlighted in the handbook but can usually make out enough of the rest of the other characters illustrated to lead to a ID. Unlike some of the other micro caddisflies a higher proportion of the catch are male, and these are a bit easier to identify. This is one of the two commonest micro caddis here (probably the commonest). Their external appearance is very similar to Ithytrichia lamellaris and like that species it typically shows a single dark patch on the top of the antennae, however this tends to be shorter and slightly further back from the tip of the antennae. The dark patch can be very faint though, and is sometimes missing altogether. One or two individuals have shown a second dark spot but this has been much tinier than the distal spot so not really resembling Hydroptila sparsa.
male Oxyethira flavicornis, North Elmham, 1st June 2019
male and female Oxyethira flavicornis, North Elmham, 9th July 2019
female Oxyethira flavicornis, North Elmham, 10th July 2019
female Oxyethira flavicornis, North Elmham, 14th July 2019
male Oxyethira flavicornis, North Elmham, 27th August 2019
male Oxyethira flavicornis, North Elmham, 4th September 2019
female Oxyethira flavicornis, North Elmham, 17th May 2020 - showing internal apparatus
male Oxyethira flavicornis, North Elmham, 20th May 2020
male Oxyethira flavicornis, North Elmham, 20th May 2020 - showing genital capsule with aedeagus
female Oxyethira flavicornis, North Elmham, 23rd June 2020
male Oxyethira flavicornis, North Elmham, 24th August 2020
Oxyethira falcata - none in 2019 but 4 in 2020 - singles on 20th June, 30th July and 15th and 27th September. The last two were my last of any micro caddisfly in 2020. This species seems to lack any distinctive external features although based on this small sample they perhaps tend to be darker than the other similar species. The antennae were also rather dark so any dark spots hardly showed up. Both male and female genitalia are fairly distinctive but the dark comma shaped sclerites on the female can be difficult to see if the abdomen is over-cleared.
female Oxyethira falcata, North Elmham, 30th July 2020 - showing the posterior lobes
male Oxyethira falcata, North Elmham, 15th September 2020
male Oxyethira falcata, North Elmham, 27th September 2020 - showing genital capsule and aedeagus
So far as I can tell from the maps at the NBN Atlas none of the other species of Oxyethira have been recorded in Norfolk, but then again there are no records of falcata away from North Elmham either so perhaps one or two of the other species might be possible.
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Family PHILOPOTAMIDAE
No representatives of this family appear to have been recorded in Norfolk judging from the NBN Atlas. Even those that are common and widespread across most of the country seem to be absent from East Anglia (Wormaldia occipatlis probably comes closest to Norfolk).
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Family ECNOMIDAE
Ecnomus tenellus - 3 singles trapped here betweeen 24th June and 17th August 2019 and a better 14 between 17th June and 8th September 2020 including 5 on 26th June. For the first time this year I've started to become confident separating at least some of these from various members of the Polycentropodidae family without checking their genitalia, although I have continued to check a selection of them. All 25 that I've checked (in these years and in previous years) have been females.
female Ecnomus tenellus, North Elmham, 24th June 2019
female Ecnomus tenellus, North Elmham, 29th June 2019
female Ecnomus tenellus, North Elmham, 17th August 2019
female Ecnomus tenellus, North Elmham, 17th June 2020
female Ecnomus tenellus, North Elmham, 22nd June 2020
female Ecnomus tenellus, North Elmham, 23rd June 2020
Next page: Polycentropodidae
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