Dance/Dagger Flies

(Order: Diptera)

Dagger/Dance Flies Mating

The best thing about these flies is their mating ritual. This whole set up seems to defy gravity - how does he manage to cling on with two legs only whilst mating with a female who is eating another insect? Female dagger flies will only mate with the male if he brings a 'nuptial gift' (i.e. a dead insect) for her to munch on whilst mating. In fact, you can see here that this lucky female was brought a mayfly, which obviously did the trick, as he certainly got his wicked way with her.  Only problem was that she seemed to be far more engrossed in the meal than she was in him.  Guess the same thing happens in humans, only she has usually finished eating prior to any coital activity. One other interesting fact - he sometimes cheats and brings her a plant seed pretending its an insect.  Seems, unsurprisingly, that she's usually not fooled. Men - what can you say?

Dagger/Dance Fly (Empis tessellata) (Waterfoot, South West Glasgow)

This is a large and quite fearsome looking fly. Its long, solid downward-pointing probosis (seen in the photo on the left) is used for spearing other insects. It is also known as a dagger fly because of its probosis. They are often found in flowery habitats and feed on nectar as well as flies.

Dagger/Dance Fly (Empis sp.) (possibly Empis livida or something similar) (Patterton, South West Glasgow)

This may be Empis livida, although there are 14 species in this genus. This insect is very like the previous Empis tessellata, but the thighs of the Empis tessellata are black, whilst the thighs of this Empis sp. are red/brown. The male’s wings are slightly cloudy, as  in the top photo, whilst the female has clear wings (as in the bottom right photo). This species is less common in Scotland.

Dagger/Dance Fly (Empis stercorea) (Patterton, South West Glasgow)

A rather attractive fly. There are a number of orangey-brown dagger flies with stripes running down their back, but this narrow black stripe makes it quite likely to be this species. The bright colouring made it quite conspicuous against the leaf and it has the distinctive dagger-like piercing mouthpart which distinguishes all these daggerflies from other similar looking flies.

Dance/Dagger Fly (Empis trigramma) (Patterton, South West Glasgow)

A small dagger fly with a yellowy-orange abdomen with a dark stripe down it. The thorax has three dark stripes down it with a slight yellow colour at each side, which is why I assume it's called 'trigramma' as there is another dagger fly called Empis digramma that only has two dark stripes on its thorax. You can see this is a female dagger fly by the pointed ovipositor. Males have a strange clubbed appendage which apparently is uses to provide her with a nutritional liquid gift.

Dagger/Dance Fly (Hybos culiciformis or similar)(Patterton, South West Glasgow)

There are a few Hybos species, so I can't be sure of the identification of this one, but they all have these distinctive large red eyes, which seems to take up their entire head, a very large and rounded shiny thorax, long slim abdomen and legs with thickened spiky 'thighs'. The very tops of the 'thighs' look yellow particularly when looking at the insect from directly above. A surprisingly conspicuous fly given its tiny size.

Dance Fly (possibly Tachydromia umbrarum or similar) (on the wall of my house, South West Glasgow)

It seems like dance flies and dagger flies used to be classified together, but now they are classified separately - not sure why. So, whilst all the flies above are dagger flies, this one is a dance fly - seems fairly obvious to tell them apart from what I can tell - dagger flies have a large dagger-like appendage coming from their 'mouths' and dance flies don't. Also worth mentioning that this would have to be microscopically examined to determine the precise species. Anyway, the pattern on this dance fly's wings remind me of road chevrons. And interestingly, when I started photographing it, I was sure it was simply going to fly off, but it just crawled up and down the wall and didn't fly off at all - weird. In fact it didn't stop crawling around, which is why, as well as it being pretty small, I couldn't get a sharper photo than this. Still, hopefully there's enough detail here to get the idea.