A Well Endowed Daggerfly!

I like empids (no not the American flycatchers, though I like those too), I'm on about the Empididae flies. Though, very much like the birds, I haven't actually seen too many of them before. Twitching the Alder Fly in Cornwall was a very pleasing experience, especially watching LGRE being forcibly told to piss off whilst trying to collect money "for the farmer" (wrong bucket, more likely it was just his petrol money home we all reckoned. Plus we'd already paid into the right bucket). But I digress, back to the flies. 

As you will hopefully be aware, this year I have been challenged by The Ghost to see which of the two of us amasses the largest combined beetle and fly yearlist. It's just a bit of fun with the idea being that we both gain a bit more knowledge in these two groups. Empididae belongs in the infraorder Eremoneura - Empidoidea which itself comprises the families Atelestidae (2 British species), Hybotidae (182 species), Empididae (208 species), Brachystomatidae (4 species) and finally Dolichopodidae (305 species), all of which amounts to a very healthy 701 species. Of which I've seen maybe ten. Max.

Luckily, I own a copy of the British Flies Vol.6 Empididae Pt 2 Hybotinae Empidinae (except Hilara), published way back in 1961. It's a bit of a beast of a book to navigate but it does seem exceptionally good, despite the numerous changes in nomenclature that have taken place these past 60 odd years. 

Anyway, I netted a male empid and did my best with it. Here's a pic of the beast in question

It's a rather smart looking critter, though only 5 or 6mm in length

One feature that immediately caught my eye was the looped 'thing' at the rear of the abdomen. I briefly wondered if it had somehow flown away with part of the female genitalia still attached. A closer look left me almost as baffled. Just....why???

Oooh! 'ello big boy...

Yep, that's exactly what you think it is - that's a penis. I bet he's a hit with the ladies! Once I'd finally finished trying to imagine how that thing is even manoeuvred into position, I thought it would be a good idea to see why the family are colloquially known as daggerflies (and no, it's not because of the size of their dick!) 

The sharp end of a daggerfly

These are a family of predatory hunting flies. They sit on a leaf or some such watching and waiting for a passing fly, then grapple it in mid-air, hold it securely in the powerful front legs and jab that flipping great proboscis into the hapless victim before sucking it dry. Males typically use these hapless victims as a pre-nuptial gift for the females, smooth charmers that they are. I've often seen a pair of empids in cop with the dead 'prezzie' on full display, the overall impression being that of a somewhat macabre ménage à trois. 

This fly's hugely elongated 'chuck it over yer shoulder' penis, combined with the three blackish stripes across the top of the thorax quickly helped to identify it as a male Empis trigramma, a common and widespread springtime/early summer daggerfly - yet the first I've identified.

I also swept a female that looks to be the same species, plus a much larger brown empid that I fully expect will run to Empis tessellata. Then there are the several far smaller hybotids that I swept from long grass/bluebell/bracken understorey. I bet they don't run through the keys quite so easily. Platypalpus is my stab in the dark (see what I did there?) 

So daggerflies are now on my yearlist for dipteran families, which puts me even further ahead of The Ghost. Whatever is he playing at, the silly phantom?

Stiched up by a Suture!

Last week I swept a small fly from a patch of Ramsons and, despite twice keying it to Tachinidae, it fell down almost at the first hurdle seeing as it lacked an unbroken suture across the thorax. I put it aside for another time, intending come at it with fresh eyes at a later date. 

Today I keyed it again and once more it dropped out at Tachinidae. That's three different keys all telling me the same thing, hmmm... It was a bristly wee thing with an inflated sub-scutellum, which fits Tachinidae perfectly, but with no suture (unbroken or otherwise) whatsoever - which clearly means it isn't one. 

I bit the bullet and keyed it through as if there were a suture. 

The fly in question

Highly inflated sub-scutellum (arrowed) - diagnostic of tachinid flies

Any suture should cross the thorax somewhere between the fly's head and the pin

I used Belshaw to key this fly and seeing as I'm very unfamiliar with the vast majority of tachinids I ran it through the key to genera first. Below is a highly abbreviated version of the route I followed

1) Very large black fly with a yellow head (no) >>2

2) Bright metallic (no) >>4

4) Arista with long hairs (no) >>15

15) Eyes with hairs longer than width of arista (no) >>74

74) Vein R1 with hairs (no) >>82

82) Vein R4+5 with a line of hairs extending beyond half-way to crossvein r-m (yes) >>83

The line of hairs extending over half-way from the node to the cross-vein

83) Parafacial area with a line of bristles not extending beyond middle of antennae 3 (yes) >>84

84) Excavation on tergite 1+2 extending all the way to rear of segment (no) >>86

Excavation only extends about half the distance to end of segment

86) Abdomen 3 and 4 without median discal bristles (yes) >>87

87) Proboscis extremely elongated (yes) >> Siphona

That's one heck of a proboscis!

You'll just have to take my word for it that the full version of my route through Belshaw's Key to Genera was far more complex than the above few lines would imply. I left out lots of detail! 

So, despite not having a suture (and hence not being a tachinid...) it keyed very well to genus Siphona (a tachinid). Online pics showed that I was in the right ball park for size and overall looks, and that they do occur in this part of the world and that they fly in the spring. Excellent! Now to figure out which Siphona it was that I had.

There are ten members of the family known to occur in Britain (or there were in 1993 when the book was published) which didn't seem too daunting. Into the next key...

1) Thorax with 3 or 4 post-sutural dorso-central bristles? You're having a laugh! I looked at my fly and tried to conjure up a suture. I saw a vague depression running from a side margin and extending maybe a fifth of the way across the thorax. The opposite side held no clues whatsoever. Taking this as my 'suture' (the book did state that sutures may fizzle out a bit towards the middle...) I counted three dorso-centrals behind it  >>2

2) Tarsal claws as long as the tarsal segment they are attached to (no) >> 3

Claws are shorter than the length of the tarsal segment they are attached to

3) Abdomen segment 1+2 with a marginal bristle at each side of the segment (yes) >>5

5) Femur of front leg with four postero-ventral bristles (yes) >> Siphona (mesnili) confusa

The leg accidentally came off, but certainly helps with the angle of photography!

These four bristles, amongst the British Siphona, are unique to S.ingerae (tarsal claws as long as the segment) and S.confusa, so that seems a pretty certain ID. I turned to the species account to see what that had to tell me about my fly. 

Buggerall really. 16 records, all from late April and into May, and only discovered new to Britain in 1993 by the author of the book! Hosts unknown. Happily the Tachinid Recording Scheme have a bit more to say about it, though even now there are still only a handful of records (21 on the NBN map).

One feature that I struggled to understand is the shape of sternite 5. Supposedly "the apex of its lobes are abruptly turned in at 90 degrees", a feature that is unique to Siphona confusa. Mine was a male, which is meant to make things easier. Here's my pic of the relevant part, you're looking at the underside of the fly's abdomen. 

And the same image but I've added red lines to show what I've interpreted as being the two possibilities that refer to the "apex of the lobes turned abruptly inwards forming a 90 degree angle" 

If you've stuck with it this far, chances are you're probably properly into your flies, so feel free to tell me what it is that I'm supposed to be checking! 

Anyway, it's a nice fly and one which I've now spent quite a bit of time with. It seems that the flight season is pretty short, so I need the temperatures to raise a bit higher than the two degrees it is at the moment if I want to find any more of these. It was snowing two days back, it didn't settle but was followed by sideways hail. Always a joy when you're approaching mid-May. 

One last pic of the beast, all labelled up and ready to go into the relevant storebox. I can see myself needing to split my Brachycera collection into more boxes before too much longer. Currently I have "Diptera Nematocera", "Diptera Syrphidae" and "Diptera Non-Syrphidae" and the latter is becoming just a tad full. Clearly I shall need to split the Eremoneura, the Acalyptratae and the Calyptratae into their own boxes at some point. 

Not too much space taken up by this one - each label is 12x7mm

Craneflies of Uig - Part 1

Up until quite recently, I'd always viewed cranefly identification as being something of a dark art, something I considered best left to professional dipterists and other assorted crazies out there. But 2020 is the year where I'm trying to tackle any flies I happen to stumble across, and that obviously includes the leggy bastards that constitute the craneflies. I have keys, I have literature, I have a wealth of online resources and I have a need to stay one step ahead of The Ghost - and he's one of those crazies that already tackles tipulids. I soon found myself wading the murky waters of tipulid ID with an open mind having made the decision to tackle whatever came my way. Which is easy to do in the opening, quieter months of the year.

So what exactly are 'tipulids'? Ok, so firstly there is a nematoceran superfamily known as Tipuloidea which houses four families, these being Tipulidae, Cylindrotomidae, Pediciidae and Limoniidae.

Tipulidae are the 'Long-palped Craneflies' with 87 British species. These are the typical 'daddy longlegs' that everybody knows. The Cylindrotomidae are the 'Long-bodied Craneflies' with just 4 British species, none of which I've knowingly seen before. Pediciidae are the 'Hairy-eyed Craneflies' with 20 British species and finally Limoniidae are the 'Short-palped Craneflies' with a huge 222 British species.  All in all that amounts to 333 species, quite a handful to get to grips with!

My cranefly year started on the 8th January with Limonia nubeculosa, a nice easy species of Limoniidae to begin with and one I've seen before. It has three dark bands on each pale yellow femur, a unique feature amongst the British cranefly fauna. I found this one skulking in the kitchen late one night. There are just a handful of previous Skye records but it is bound to be widespread. 

My second cranefly was another Limoniidae, though somewhat smaller in stature. This is Dicranomyia chorea, another nationally common species but with only two previous Skye records, both from 2009.

The upper image is of a female that I potted from beneath Mark Telfer's window sill when I was in England earlier this year. The lower image is of a male that I caught here in Uig and shows the diagnostic terminalia which I'd hinged open to view. Despite not knowing what it was I had captured, it keyed to Dicranomyia very easily and the wing venation/pattern and genitalia are clinchers. So that's two out of the three hundred and thirty three possible species done - so far so good!

I had to wait until mid-March for species No.3 to make an appearance, a gnat-like wee thing spotted as it rested on the underside of a branch in Uig Wood. 

This is a fairly undistinguished fly, though the hairy eyes immediately place it in Pediciidae and the wing venation quickly puts it in the genus Dicranota. It keys through straight to Dicranota subtilis, one I've never identified before. There are only two previous Skye records, both from the same chap in 2009, so it's nice to be able to add an updated record.

It wasn't until the end of March that I found what I had initially figured would have been my first cranefly of the year, spotted whilst fixing a broken window catch. This is Tipula rufina, a common species often encountered in the early part of the year and exhibiting patterned wings and a hugely diagnostic black streak running horizontally across the pleura.

This was my first Tipula of the year, a proper decent sized beast more readily recognisable as a cranefly rather than a large gnat. I saw a handful more over the next few weeks, but not as many as I would have expected to find. Maybe they're having a slow start to the year, or maybe I'm just not checking enough windows. Rather surprisingly, there are just two previous records for Skye (one being mine) and another from nearby Raasay. 

An entire four weeks passed before the next Tipula was recorded, but it was well worth the wait!

This is the rather lovely Tipula vittata, a common springtime species typically found in damp woodland across much of Britain. This is just the third modern record for the species on Skye, with the only other being a 1939 record. 

After the excitement of a decent Tipula, it was back to a small drab thing once more. This one keys to Dicranota pavida on account of the hairy eyes, a single wedge cell in the lower part of the outer-wing and an extra cross-vein in the upper part of the wingtip. There are no previous records of this cranefly from Skye.

My final cranefly of the spring thus far was found this morning, perched up on the wall of the laundry shed, presumably attracted in by the overnight light. I didn't have my camera or a pot to hand, so shoved it rather unceremoniously into a cup that was sat on the side.

The thirteen antennal segments, wingtips extending beyond the abdomen and narrow gap between the underside of the eyes all distinguish this as Tipula oleracea and not the similar Tipula paludosa, which flies quite a bit later in the year. 

So, the first five months of 2020 has provided me with seven species of craneflies and has resulted in no major issues or mental breakdowns. Maybe they are do-able by lesser mortals after all. Mind you, identifying seven out of 333 species hardly makes me an expert on the subject! I'm certain I'll come tumbling down to earth with a bump soon enough.  

I entitled this post Craneflies of Uig - Part 1 which kind of implies there will be a Part 2, maybe even a Part 3. Who knows where this could end (not me!) Well the tipulid season is about to kick off and I plan to keep abreast of identifying the ones I encounter as best I can. So yeah, there will definitely be a Part 2, probably for the summer jobbies, and a Part 3 for the end of summer species. Maybe even a Part 4 for the late season ones, who knows?

This is my breakdown so far :

Tipulidae - Tipula rufina, Tipula vittata and Tipula oleracea
Pediciidae - Dicranota subtilis and Dicranota pavida
Limoniidae - Limonia nubeculosa and Dicranomyia chorea
Cylindrotomidae - not yet.

Dipteran Moments

Throughout the course of a typical year on Skye I would ordinarily encounter well over 1000 species, ranging from earth-tongues and barnacles to clubmosses and stoats, from harvestmen and sedges to wild swans and gnats in the winter. Clearly this is not in any way a typical year, here or elsewhere. 

There are several species in particular that I look forward to seeing each year. The happy level of keen anticipation as that inevitable moment of encounter draws ever closer can sometimes become quite intense. The current restrictions mean that I'm going to miss seeing some of these species this year, but there are others I can find locally. 

There are a handful of inverts on this keenly awaited shortlist, including a couple of flies. The sight of the year's first Gymnocheta viridis iridescently glinting greens and bronzes on a sunlit tree trunk is one such moment. I had a long wait this year, right up until 21st April in fact. Note the lack of leaves in the image below, winter has been reluctant to let go this year.

My first Gymnocheta of 2020. It's what could probably be called a Record Shot...

Happily I did get ever so slightly closer. What a fly!

Plant-wise, there is one very clear winner for me. I can't really explain quite why, but I have a strong love of wandering through carpets of freshly-emerged Ramsons. Maybe it's being beneath deep tree cover. Maybe it's the exquisite flowerheads or the rich smell (and sharp taste!) of garlic. Maybe all of these things combined, I just can't say. But I do love Ramsons. Happily for me, it's a common plant throughout much of the wetter areas of Uig Wood and at this time of year, just as the flowers are opening up, I make a special effort to seek and photograph a certain fly inextricably linked to this plant. One that just happens to also be on my shortlist of keenly anticipated species.

  

This is Portevinia maculata, also known as the Ramsons Hoverfly. These individuals are males with their enlarged eyes. They can typically be found sitting on sunlit Ramsons leaves, wings held partly spread revealing the silver markings on an otherwise all-black body. For a hoverfly they are pretty slow, almost clumsy seeming in fact, as they bosh and crash their way through leaf blades and flowerheads, almost always settling again within just a few seconds. Flight seems a bit of an effort for them, in fact the females usually just walk around on the underside of leaves. At least the males come out to sunbathe and offer themselves up for some pics. 

This is almost the full extent of the Ramsons bed at the site in question. There are a few bushes, and a row of young trees just out of shot to the left, but these Ramsons are essentially living outside of their usual deep woodland habitat. It's a weird plant here on Skye, I've seen it growing in shaded nooks between large boulders on hillsides with not a tree to be seen for miles around. However, this patch is clearly benefitting from the open aspect as it is flowering far sooner than are the extensive carpets in Uig Wood, most of which is still in the leaf only stage.

You can see my rucksack and fleece in the background (they were quickly shed in this sheltered suntrap!) I spent a merry hour or so walking a line back and forth between those and the spot I stood to take this photo. In fact, most of my time was spent walking a ten foot track from my rucksack into the patch and back. I estimate that I counted around a dozen different Portevinia in that small area, all males. I'll go back and see if I can find some females soon, maybe they emerge later than the males?

In case you're wondering, I passed one person as I was heading down to the woods (my housemate, as it happens) and none at all coming back. That was it. Uig is not a heavily populated spot.