Large, blue-black, loud fly
We had four or five of these flying around the house in early May, and I caught this one on May 13, 2012. They were similar to the standard housefly, except they were about 50% longer and broader, noticeably more black, and four or five times noiser than a housefly.
Their main annoyance factor was that they just wouldn’t settle down and be quiet. They would fly constantly for what seemed like hours, with a rasping, droning noise that was impossible to ignore. Particularly when we were trying to sleep. When I caught this one, I had to put it in the refrigerator for a bit to get it to settle down enough that I could get pictures.
It had the standard behavior of a lot of flies where it would sit there and rub its forelegs together.
Looking around BugGuide and comparing size, shape, and general wing vein pattern, I think it is one of the larger blow-flies (family Calliphoridae). It looks most like some of the flies in the genus Calliphora. Specifically, it looks to me a lot like the very common blowfly Calliphora livida.
The antennae are a bit weird. Mostly they are these things that look like a couple of sausages hanging from the middle of its forehead, but each antenna also has a secondary antenna projecting from its side that looks a bit like a branch.
I had a really hard time getting it to face me, and never did succeed in getting a face shot. Most of the time, it would spin around to present its rear to the camera no matter how I rotated the paper it was sitting on. So, fine. Here’s a couple of pictures of the abdomen.
The abdomen is rather hairier than that of most of the flies that resemble houseflies, with the longest hairs being at the edges of the abdomen segments. There is a slight metallic sheen to the abdomen, but not as extreme as is seen on some other blowflies (the “bluebottle” and “greenbottle” flies).
Their maggots mostly eat dead animals and rotting manure, so the fact that we had several of them get in the house suggests that something either died or left droppings somewhere nearby. And that these flies either hatched out of it, or came looking for it.
Blowflies like these are one of the things that forensic entomologists use to determine how long a body has been dead. They know how long it takes for blowflies to find a corpse, and how fast they mature for given weather conditions. So, by finding blowfly maggots and pupae in the corpse and determining how far along they are, they can work out how long a dead body has been exposed to the elements.
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Flies that never seem to land sort of intrigue me (while simultaneously irritating me). It doesn’t seem like they should be able to keep that up for so long. OK, they don’t weigh much, but still, they must be ridiculously efficient.
Yes, I wonder about that too. Especially when I’ m standing there with a flyswatter, thinking, “Come on, come on, land somewhere already! Don’t you ever get tired?”
I also wonder how much of their energy goes to actual flight, and how much gets dissipated as noise.
(Incidentally, over the past summer I’ve found that a short-handled insect net is often more effective than a flyswatter, because a net can snatch flies out of the air without having to wait for them to land.)
Wow, those ARE freaky antennae. I like the pale blue color on it’s fanny. Maybe that’s why it was so proud of same.
I recently read that forensic folks have tested some of their assumptions re: body decay rates outdoors, how long it takes for vultures (in particular) to find them, etc., and they have learned there’s LOTS more variation in decomp rates that they’d thought. However, this may not be the case w/flies. Part of why I love biology–never ending complexity keeps us learning/guessing all the time. =)
Are these cluster flies? They seem to like to overwinter wherever they can get in. Then we see them in spring when it warms up in the attic or wherever they have been hiding.
Here’s a bit on cluster flies from Wikipedia. They are parasites on earthworms which is fine in my area of Ohio where we have no native earthworms. The photos did not come through but you can look them up yourself and see that they are similar to those of our host at the Backyard Arthropod. Actually they are kind of pretty close up.
Cluster fly
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Cluster flies
Male Pollenia sp.
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Diptera
Family: Calliphoridae
Subfamily: Polleniinae
Genus: Pollenia
Robineau-Desvoidy, 1830
Type species
Musca rudis[1]
Fabricius, 1794
Species
See text
The cluster flies are the genus Pollenia in the blowfly family Calliphoridae. Unlike more familiar blowflies such as the bluebottle genus Phormia, they do not present a health hazard because they do not lay eggs in human food. They are strictly parasitic on earthworms; the females lay their eggs near earthworm burrows, and the larvae then infest the worms. However, the flies are a nuisance because when the adults emerge in the late summer or autumn they enter houses to hibernate, often in large numbers; they are difficult to eradicate because they favour inaccessible spaces such as roof and wall cavities. They are often seen on windows of little-used rooms. They are also sometimes known as attic flies.
The typical cluster fly Pollenia rudis is about 7 mm long and can be recognised by distinct lines or stripes behind the head, short golden-coloured hairs on the thorax, and irregular light and dark gray areas on the abdomen. Cluster flies are typically slow moving.
Cluster flies have a widespread distribution. Eight species are found in Britain and thirty one in Europe. Pollenia species are also numerous in Australia and New Zealand (over 30 spp); they are a common pest in North America. P. rudis has spread widely in association with humans.
I once squashed a fly on the windowscreen and out popped live maggots! YUCK! I love bugs but that was just…yuck. Ever heard of such a thing? I thought they only laid eggs. I’m pretty sure it wasn’t it’s guts.
On a related note, why do flies rub their forelegs together? I’ve always wondered.
Reminds me of a poem by Emily Dickinson
I heard a fly buzz when I died;
The stillness round my form
Was like the stillness in the air
Between the heaves of storm.
The eyes beside had wrung them dry,
And breaths were gathering sure
For that last onset, when the king
Be witnessed in his power.
I willed my keepsakes, signed away
What portion of me I
Could make assignable,–and then
There interposed a fly,
With blue, uncertain, stumbling buzz,
Between the light and me;
And then the windows failed, and then
I could not see to see.
-Dickinson
The fly looks like an alien. Like a Kafka fly.
But he could also be a Dickens character. He is rubbing his hands (I mean forelegs) in that second photograph —in a sort of provocative, expectant fashion. That pose seems almost like he should be a beadle from Oliver Twist, calculating up how much money he is saving by starving the pauper children or he could be the ring leader of a group of young pickpockets about to rob a dandy.
I had no idea that these flies were so interesting in terms of construction. Just the wings alone make this one a dancing object.
The wings are very ballerina-attire and vein pattern on the gossamer wings are very delicate. He could almost be pretty. I like his name as well and so appropriate! – Calliphora livida—he is livid and loud.
The mug shot (photograph #3) is incredibly intricate (I never realized a fly was so complicated what with those bulging orbs, the hairs all over, the two antennae sets). He seems like he is a messy eater as well what with all the tiny bits of residue of stuff all over him. He has so many pointy bits all over him (hairs) that this macho surface seems to contrast unhappily with the Peter Pan wings.
Happily it snowed today in Edmonton so all our bugs are knocked out. I’ve not seen a fly for ages and I’ve never encountered one of this magnitude but I’m not often in the vicinity of dead creatures unless it is a roadkill that the magpies and crows are squabbling over and usually these poor Snowshoe hares and squirrels (typical victims for our road-rage warriors on the city streets) are not liable to be kept on display to get to blowfly consumption stage. I did see a sparrow on the soccer field but it had been hollowed out to feathers and beak by ants and so if there had been flies it must have been a rapid autopsy and decomposition process.
But I must not bore you with the grisly finds on the city pavements and soccer fields. This fly was a whopper. A Kafka fly.
Here is a bit from Kafka to give you a taste of what this fly conjures up in my mind when I see him:
http://www.gutenberg.org/files/5200/5200-h/5200-h.htm
His sister began to play; father and mother paid close attention, one on each side, to the movements of her hands. Drawn in by the playing, Gregor had dared to come forward a little and already had his head in the living room. Before, he had taken great pride in how considerate he was but now it hardly occurred to him that he had become so thoughtless about the others. What’s more, there was now all the more reason to keep himself hidden as he was covered in the dust that lay everywhere in his room and flew up at the slightest movement; he carried threads, hairs, and remains of food about on his back and sides; he was much too indifferent to everything now to lay on his back and wipe himself on the carpet like he had used to do several times a day. And despite this condition, he was not too shy to move forward a little onto the immaculate floor of the living room.
Metamorphosis
Franz Kafka
Translated by David Wyllie
Katbird: While cluster flies are similar to the fly in this posting, I have had pictures of cluster flies on this site in the past, and they have some subtle (yet distinctive) differences when viewed close-up. Specifically, they have golden hairs on their thorax, and do not have the metallic-blue sheen on their abdomens. Plus they aren’t that much bigger than house flies.
JennyW: Some flies are “ovoviviparous”, meaning that their eggs hatch before they are laid and the mother fly gives birth to live maggots. This is apparently common in carrion flies. There is a lot of competition around carrion (a very concentrated source of nutrition that only lasts a little while), so time is precious and their maggots need to get eating right away rather than taking the time to wait around for eggs to hatch.
Bridget: The rubbing of the legs is the last step in cleaning themselves. Flies groom themselves all over with their legs to get rid of dirt, which transfers all the dirt to their legs. Then they rub their legs together to knock off the last dirt, and they are clean. Well, as clean as a fly ever gets, anyway.
Sam: Thanks for the poem!
Julie: Yes, “The Metamorphosis” is certainly an interesting story. Kind of disturbing, but interesting.
Cluster flies CAN have that colouring. It is a cluster fly. The overlapping wings is the distinction.
David:
I believe you are mistaken. The wings are only partially overlapping, which is something that pretty much all flies can do (for example, this blowfly from BugGuide has just as much wing overlap as my specimen).
I’ve seen lots of our local cluster flies, which are much smaller (only about 2/3 the size of this one), look distinctly different, and actually do rest with their wings fully (not partially!) overlapping. This is not one of them.
Calliphora vicina?