Chromatomyia paraciliata

Gilbert has been a bit quiet about the fly / beetle challenge of late but what can I say? Rubbish weather followed by lockdown in a crappy urban environment means there really hasn't been anything worth mentioning. On the few occasions that I've managed to get to any decent habitat, flies seem to have been really thin on the ground. Maybe it's normal for this time of year and I don't usually notice because the weather is sufficiently poor to discourage me from doing any fieldwork.

Anyway, within a reasonable walking distance of my house is a 'park' with loads of mown grass and far too many people and a wood which I've never been to because from the outside it looks like a horribly dark, dull conifer plantation. I did try going there once and it isn't quite as bad as that but it was crawling with people so I haven't been back. In desperation I thought I'd try the burial ground at the top of the high street. It's basically a churchyard without a church and sometimes churchyards can be quite interesting so it was worth a look.

A notice board at the entrance explains that part of the site is mown in early spring and part in the autumn and only a small area mown regularly so that seemed quite promising and there was quite a diverse sward, probably mostly originating from planting but still better than nothing.

One of the first things I noticed was lots of Ox-eye Daisy so I had a quick look for the moth Bucculatrix nigricomella. No sign of that but lots of fly mines. The pupae were in the mine so I brought a few back to breed the adult fly. A check of the UK Fly Mines web site suggested that it was most likely to be one of the common species pair Chromatomyia horticola / C. syngenesiae which need dissection of the male fly to identify. There was a possibility that it might be C. paraciliata but there wasn't much information about that anywhere on the web.

Chromatomyia paraciliata mines in Ox-eye Daisy basal leaves

A few days later a male and a female had emerged from the mines so I sent the male to the national recording scheme organiser for dissection. It turns out it didn't need dissection as it wasn't one of the common species pair but I'd never have identified it myself anyway as paraciliata isn't in the Agromyzidae key, having been described new to science in 1985. Barry identified the specimen and emailed me within a few hours of receiving it. He tells me that there are less than half a dozen records in the national database and all are from the original finder so I might be only the second person to find this species in Britain. Abroad it is known from mainland Spain and has recently been identified from Italy by Barry.

Chromatomyia paraciliata pupa

Maybe urban recording isn't as pointless as I feared.

Sponge flies

I take a break from the fly/beetle challenge to post something about sponge flies because there seems to be very little about them on the web and the British key is a little misleading. Hopefully this blog might save someone a bit of time in the future.

For the uninitiated, sponge flies are no more flies than butterflies are. They have four wings and therefore cannot be Diptera (although much of the information about them on the web seems to be on Diptera.info). They are actually Neuroptera - lacewings. There are only three British species so how hard can it be?

The most recent British key is the lacewings AIDGAP key. It illustrates the male genitalia so there shouldn't be any difficulty with males. Unfortunately I had a female. The key starts by separating out the rare Sisyra terminalis on the basis of both sexes with ends of the antennae distinctly pale, as opposed to both sexes with antennae dark for their entire length.

Ok, so it's a fairly rubbish photo but you can see that the ends of the antenna are distinctly paler. Bloody hell, I've got terminalis! Apart from its rarity, the main problem with this as a determination are that it 'appears to favour streams that are overhung with trees' when I caught it by a large lake. But it does say 'appears' so maybe that isn't a problem. I am uneasy though about how distinctly pale does 'distinctly pale' have to be. The out of print RES key is a bit more precise; Antennae blackish with the apical fourth pale yellow; wings grey, almost colourless, cross-veins pale. Well my specimen certainly doesn't seem to have pale yellow tips to the antennae and a quick Google image search produced images that had much paler tips to the antennae than mine. BUT, these were live insects, how much does the colour change on two year old dead specimens? My specimen still cannot be said to have antennae 'blackish throughout' which is the alternative in the RES key.

I then came across a Spanish key. The Spanish fauna only includes one of the three British species, S. dalii. This key also starts with antennal colour but 'antennae of similar colour and tone' does NOT lead to S. dalii, instead that comes out if you follow 'antennae of different colours or tones'. So that opens up the possibility that my specimen is one of the other British species. The AIDGAP key separates these on 'forewings uniformly coloured, the cross-veins scarcely darker than the membrane' versus 'forewing not uniformly brown, membrane lighter than many of the veins and with small but distinct darker marks, at least around the cross-veins'. The RES key words it slightly better but has the same criteria.

My specimen clearly has darkening of the cross-veins and also the area where the anal vein meets the hind edge of the forewing so my specimen is Sisyra dalii. However the AIDGAP key says that this is extremely local and scarce, with most records from rock-strewn, fast flowing upland rivers (although it is also recorded from the slower and calcareous River Mole in Surrey). This description hardly fits with a lowland lake on clay in West Sussex but the RES key says that all three species are found in similar situations; 'frequents the sides of streams and less often ponds'.

Finally I include a picture of the female terminalia as there don't seem to be any images on the web. I have no idea if they provide any help with identification but at some stage I'll dig out my specimens of S. fuscata and see if they look any different.

A slag of a ladybird

On Saturday I visited the sand dune system at West Wittering with 'The Lyons'. He had surveyed the site last year so had a pretty good idea of what we might find, albeit that there were bound to be new species for the site, even when the fauna is specialist but species-poor. The weather was not too bad for the time of year but an increasingly strong wind made life difficult and my net, which I carried round throughout, remained unused. Instead we relied on tussocking, sieving and his vacuum sampler; techniques that I very rarely use. The resulting catch was primarily spiders and beetles (hence why I rarely use these techniques) and the average size of the specimens was best measured in micrometers!

Graeme was able to identify a lot of what we caught but if I just ticked off everything he said, it would defeat one of the main objects of 'The Challenge' - learning stuff myself. So I took a bunch of specimens of things that I thought I might have a fighting chance of doing and made some notes of Graeme's suggestions so I'd have a pretty good idea if I'd keyed things properly. More than two days later and I'm not even a third of the way through the specimens and I've got three definites, a probable and an 'errrrr' out of the beetles.

Apologies for the poor photos but it's a case of spend time getting decent photos or write the blog.

Pseudaplemonus limonii - a rather nice weevil off sea-lavender

Cordicollis instabilis

Coccidula rufa

All three of these were lifers for me! I then had a look at an Otiorhynchus weevil. I got as far as ovatus or desertus with something vaguely approximating to a degree of confidence. Duff separates these by the tooth on the hind femur being 'long and sharply pointed' or 'very small and obscure'. Well that's bloody helpful, how long, how pointed? The RES key was more helpful in that it says the tooth should be as long as the width of the tibia. Well the tooth is much shorter than the width of the tibia but other features don't fit well with desertus so.....

On to the subject of the blog title. The ladybird in question is less than 1.5mm long but it's a ladybird, how hard can it be? Well, my go-to book for ladybirds is the Naturalists Handbook but a bit of a Google had suggested the best fit for my specimen might be Nephus redtenbacheri and that isn't in there as it was found in Britain since the book was published. So I tried the Bloomsbury Field Guide which according to the 'celebrity' endorsement on the back is the 'definitive field guide to ladybirds'. Well it is the definitive guide only if your idea of identifying things is to look at a picture and say 'well it looks like that one, that'll do'. For a group of species that are extremely variable in appearance, to have no key, no clear cut features to separate similar species, etc. is far from 'definitive' to my mind. Anyway, Mike Hackston came to my rescue as he so often does; a decent key in intelligible language. So I fumbled my way through to couplet 18 which asks whether there are ridges on the process on the prosternum. Seriously? The whole beetle is <1.5mm! Even at 80x magnification I had no idea so I took a photo and looked at it on the laptop.

So has it?

I was hoping for a nice smooth process where it would be easy to see ridges. On this bloody thing I had no real idea but plumped for yes. This eventually took me to a group of Scymus species, none of which looked like my specimen so I tried no. This took me to the question of how many antennal segments does it have? Oh come on! Again, the whole beetle is less than 1.5mm.

How many segments then?

One option took me to just one species and it didn't look right for that, the other took me to a pair which includes Nephus redtenbacheri. So I guess that's probably what it is but identifying things through a route where you cannot clearly identify features that you need to see is most unsatisfactory. It retains a ? on the label.

Nephus redtenbacheri?

 Fortunately, I did pick up a few flies which have been much easier to key. Two Lonchoptera lutea and a Geomyza tripunctata both provided new families for the year, as did a Chloropid which I haven't tried to key yet.

Geomyza tripunctata

Time for an update

Most of my spare time at the moment has been taken up with working through my backlog of specimens. This is the most productive way to spend this time of year but I cannot let the competition think he's having it all his own way so I've done a bit of fieldwork in the few moments of decent weather to get the lists up and running.

Flies have been thin on the ground even then but I've picked up a few cluster flies attracted to the white walls of a friends house and on the windows of a barn at Knepp. Most of them have been Pollenia species which need a bit of work in due course to get to species but I have added Calliphora vicina to the year list.

Calliphora vicina  (Wikimedia Commons)

Also attracted to the walls of my friends house was the Heleomyzid Heteromyza oculata.

Heteromyza oculata - BioLib.cz

As well as the fly and beetle species challenge, I appear to have been roped in to a fly families challenge. This involves seeing how many different families we can find and identify. The identification only needs to be to family level, not to species. So as well as the families where I have identified a species, I can also add Scathophagidae, Phoridae and Muscidae from Knepp. I have never looked closely at Phorids before but they are fairly easy to identify to family level, having characteristic reduced wing venation. I was particularly impressed with their faces though, especially their antennae with mini-footballs for the third antennal segment and sideways pointing arista. I suspect that getting them to species will be a struggle but I've ordered the key so watch this space.

Phorid head and wing

I also found a moth fly or drain fly (Psychodidae) in my bathroom and then, whilst lamping in Botley Wood the same evening, another species from this family. This family is normally a no-go area for normal people and they almost all need dissection and are horribly difficult but the specimen I found at Botley was unlike any I have seen before and I just wonder if it might be identifiable when I can access a decent museum collection in a week or so.

Moth fly from Botley Wood

Beetles will always be a secondary consideration for me in the challenge (mainly due to my inability to identify most of them) but I have picked up the very common Tenebrionid Nalassus laevioctostriatus which was crawling up a tree trunk at Knepp and the common ground beetle Dromius quadrimaculatus at Botley Wood.

Dromius quadrimaculatus

So I finish January on the 'grand' totals of 3 beetles and 4 flies to species and 6 fly families. I may be trailing in last place at the moment but that could change tomorrow when I'm spending some time in the field with a Coleopterist (if I can stop him looking at bloody spiders). 

Challenge update

Seth has a weeks head start on me but I have managed to record a couple of flies and a beetle since the start of the year. Firstly the fly Phytomyza ilicis, the mines of which can be found on virtually every holly bush in the UK - apart from northern Skye (hahaha). Another fly in the same genus, Phytomyza chaerophylli mines the leaves of umbellifers such as Cow Parsley and I found large numbers of mines at Warblington cemetary when I called in to see the various paper bags there (aka 5 Cattle Egrets and 10+ Little Egrets).

Phytomyza chaerophylli mines

Assorted paper bags

As I said in the previous post, I am utterly useless at beetles but I found one under a log whilst looking for springtails at Hindhead Common the other evening. Given its appearance and location I assumed it was a carabid and, being blue and orange I thought it would be relatively easy to identify. It very quickly fell out of the carabid key so I resorted to using a picture book to see if I could find something similar. Much to my surprise I quickly came across a suitable looking thing in the family Erotylidae - apparently called 'Pleasing Fungus Beetles'! Of the ones in the book, mine looked a good match for Triplax aenea and searches on the web haven't changed my mind but I would like to get confirmation before I count it as it would be a new species to me and identifying beetles by picture matching is seriously dodgy.

Triplax aenea - hopefully

So I reckon that puts me on about 2 and a half combined total for the year. Not sure what Seth is on but I think he's ahead of me, for the time being.

Game On

My mate (yes, I only have one) Seth comes up with a natural history challenge each year. He creates a new blog to document what he's doing and then by about mid-February he gives up! This year his challenge can be found here

So his aim this year is to focus on beetles and flies and to identify as many species in each group as he can, with the aim of becoming more competent in the identification of these groups. This got me thinking. I am completely useless at beetles and slightly less useless at flies but would like to improve my skills in both groups. A little friendly competition might provide motivation to us both so last night I challenged Seth to a competition. The challenge was accepted.

The winner will be the one whose combined total number of species of flies and beetles recorded during 2020 is the higher. The species can be recorded in any life stage and we can get help with identification from other people as it is impossible to define a clear-cut line between doing it all yourself and just mindlessly asking people 'what's this?' that makes any sense. Neither of us is the type to just collect vast numbers of specimens and get others to do all the ID work anyway, and if we did it would sort of defeat our original object of improving our ID skills.

We both have advantages and disadvantages in this challenge. Seth is much better at beetles than me and I'm probably better at flies than he is although neither of us would describe ourselves as competent in either group. I live in the tropical south of England whilst Seth is in the tundra wastelands of Skye so I have access to a greater number of species, but Seth can largely devote his natural history time to the challenge whilst I have commitments with other taxa that I cannot ignore for the year.

It's going to be interesting to see how we get on. I honestly have no idea who will win and am largely relying on Seth giving up in mid-February to give me an easy win (and subsequent bragging rights for about the next 10 years). Whatever happens, there should be some good banter for the next five weeks (or however long Seth lasts).