Andrew777's picture

Vestigially winged fly

Observed: 9th June 2011 By: Andrew777
Vestigially winged fly recuperating
Vestigially winged fly where found (1)
Vestigially winged fly where found (2)
Vestigially winged fly stunned

Apparently a house fly with vestigial wings.
The photo shows a single (same) specimen and is approximately 6mm long (eyes to tail). This is one of hundreds I have seen in my garden; since they are rapidly consumed by birds I assume that they are being produced by some other means than self propogation!
They walk at about 30mm per second.

  • Mutant housefly (Musca domestica (mutant))
    Confidence: It might be this.
Species interactions

No interactions present.


Dioctria's picture

Freshly Emerged

I think all freshly emerged flies have their wings scrunched up like this, just as the would have been inside the pupal case. They would then 'pump them up' as dragonflies do theirs, and allow them to dry before flying off.

I'd guess that either the blackbirds are getting in too quickly for them to complete this, or perhaps something is causing them to fail to achieve the 'pumping up'.

Given that you are seeing so many, perhaps the blackbirds have also got wise to a big hatch of these flies and are on the look-out for them!


I love ecology's picture

Mutated houselfy

Hi, did all the flys in the surrounding area have the same phenotypic (visual) appearance of short wings and dark body? was there many flying near the area too?

It is certainly a mutation..where a wild fly has mated with a mutated fly and and as readily observed in drosophila the fruit fly - wing mutations, eye and body colour tend to be carried on the sex chromosomes (normally the x chromosome) and like humans they have xy (male) and xx (female)chromosomes.

I also agree with andrew777 that the mutation is possibly a result of chemical or physical attack and due to the nature of flys- they breed so quick it does not take long to get alot of mutated flys! However not being able to fly- im sure they will fall back into the food chain very quickly. :-)

Andrew777's picture

Mutated Housefly

Sorry for late response.
@ The Man who can:
All had the "wingless" flies had this appearance, the dark colour I think is due to the photograph being taken against a white background; the pictures taken outside show a lighter colour - but it's the same fly. Since about two weeks ago they have disappeared until today when I saw just one more. My garden has however become very popular with sparrows, so maybe they see them before I do. The weather has become colder also, so I suppose breeding cycles have dropped.
The general fly population (of flying houseflies) have the same body colour but completely normal wings.

I should add that my "green" bin (compostible waste) gets emptied fortnightly, and I think at the height of the "infestation" I may have missed a go; so possibly they were all breeding in this rather fly friendly environment.

I did wonder whether all flies started off like this, but I cannot find any clear references, and I don't believe that this is so (or else occurs very rapidly - in a far shorter time than these things spend walking around).


Dioctria's picture

So far as I'm aware all

So far as I'm aware all Diptera do emerge from their pupa with their wings scrunched up like this, but as you say, expansion occurs much more rapidly than in the Odonata so couldn't in itself account for your observation.

I agree that some genetic or environmental factor must have been preventing them from producing normal expandable wings. A fascinating find!

Out of interest, here are some interesting shots of expandeding Dipteran wings from Flickr: ("2 to 3 minutes expansion") (start of a series) (start of a series)