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