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A brief sortie in the garden on Saturday 5th January provided three species for some ID practice. Walking on the calm water of the pond there were a number of small Dolichopodids - 3mm wing, greenish black. There was a Lonchoptera sp.: these were frequent early last year in March. I had a bit more trouble with the third, see photo - a black midge with 3mm wings, with antennae with only 6 segments. I have concluded from Stuart Ball's family key that it must be a chironomid, but the family description says that there are "generally" 13-17 segments in the antennae. Have I got the right family, and if so how many species have only 6 segments in the antenae?
PS no sign of Calliphora vicina on sunny mornings this week.
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I've only IDed a few species of Chironomids so I am in no way an expert, but the marine subfamily Telmatogetoninae have 6 segmented antenna. Thalassomyia frauenfeldi is the only species from that group listed in my books with normal sized wings. I can't find any decent pictures to compare it to unfortunately.
Edit: To clarify, according to Pinder (1976) on UK Chironomids, only the Telmatogetoninae have antenna like this. The UK only has two representitives and the other species is brachypterous.
Last edited by Gordon (2013-01-08 13:10:45)
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Thanks for these responses. I am reassured that this IS a chironomid - there didn't seem to be any other possibilities. This is 20-30 miles from the sea so I'm a bit doubtful about Telmatogetoninae, but I guess it could be carried inland by the wind. It will be interesting to see if I get any more like this. According to NBN gateway, Thalassomya frauenfeldi [sic, no i in the species name] has been recorded only on the Sussex coast.
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Next to no-one records chironomids so the NBN records aren't reliable indicators of species distributions for this family. Pinder doesn't have any detailed ecology of the species in it, so for all I'm aware "marine" could well cover a range of briny condition.
Assuming Pinder isn't hopelessly out of date, the thing to check would be the postnotum. In most subfamilies there is a distinct groove down the middle of the postnotum which is missing in the Telmatogetoninae. The only chironomid it could be if this groove was present would be a Orthocladiinae with damaged antenna.
Last edited by Gordon (2013-01-14 13:50:37)
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You'll note in Stuart's description of the Chironomidae that he refers to "13 to 17 [antennal] segments" ... "in the male". Female chironomids (like the one in your picture) regularly have far fewer segments. I can't be sure from your photo which subfamily you have, but in any case if you want an ID - try to catch a male (usually the ones with the "bottlebrush" antennae).
Last edited by Tony Irwin (2013-01-14 15:27:48)
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Ah, my apologies. I've led you completely astray, Tony is completely correct.
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I suspect this time of the year the Dolichopodids where Campsicnemus sp?.
Did you not ID the Lonchoptera?
Mark
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Thanks for the clarification on the choronomid: not one to pursue further, I think.
On the Lonchoptera, I had the ID of lutea from Martin Drake last year at Preston Montford. I was on the introductory course and got a bit stuck using the HIBI section myself. I may try again if I get hold of a copy of the key. Dolichopodidae are definitely beyond my current scope.
Last edited by pbrighto (2013-01-15 19:08:37)
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