Masses of these small March flies were out today in a riverside meadow. Some were holding their wings open showing single black spots on them.
No interactions present.
Quite likely to be B. johannis, with that clear-cut black stigma, but cannot be sure without seeing other features. I am keying out quite a few at the moment and they are all lanigerus or johannis, so far.
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Yes it looks less likely to be B marci , I'd be interested in the keying of the other two species I think a Genus is safest ob ( despite jumping in too quickly on this one )
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Male marci have the costal cell darkened, whereas this fly does not; but it does have the clear-cut black stigma of one of the smaller Bibio species...probably johannis, as I said above.
Many thanks for the input on this WLR and Ophrys. I have some other angles that may help for ID. Which views would help most? I think I got shots of B lanigerus at another location recently - with more red on the legs and tufty grey hairs near the base of the abdomen. These were a similar small size, but with all-dark legs and far less hairy abdomens. By memory B. marci is bigger but I'm not sure re other details to look for. I saw and photographed masses of them in Cornwall last year, but later in April.
Nick Upton, naturalist and photographer.
Thanks Nick Yeah thats really useful and helps test the keys . These can be quite tricky how much can be be got from the Photo to key is always difficult hoppefully Ian can Nail it - A nice macro by the way The closely related Heather Fly (Bibio pomonae)is a good ID - for the reason you State Red on legs and is closely related
You need to be able to see the front tibia, to see the relative lengths of the two apical spines. A view of the hind leg, to see the shape of the femur and tibia, as well as the basitarsus, is useful. The number of segments in the antennal flagellum is required, as well. Then, a view of the wing venation is good, to see the relative lengths of the basal section of R4+5 and and the cross vein r-m...etc.
Quite a lot, then, really, if you want to key them out properly!
I still think it is probably johannis.
Thanks again WLR. Will post the other one soon. And many thanks Ophrys. You've asked for a lot... and I've done my best, but am running out of pixels on these crops...! Camera, lens and processing all at their limits on this little fly!
I think there is enough in these pictures to make johannis the likely ID. The tibial spines are different lengths; the basal section of R4+5 is the same length as r-m; the hind femur and tibia swell from before half way; the antennal flagellum has more than 5 segments; the legs have red sections; the posterior veins are paler than the others; the notum is shining; stigma blackish and clear cut; posterior basitarsus about three times as long as wide.
However, I would always prefer a specimen under a microscope to claim the ID properly!
Many thanks for checking this out. All sounds good for this species. No specimens taken - at least not by me.. The dung flies were feasting on them tho...
Thats Great - to nail these a bit more specifically , fantastic , set of Macros Nick , i am sure Ian would agree , ...If they where only all like that and a good bit of deductive keying
I've admired Nick's photos for a long time, after seeing them on other sites...like diptera.info. Good to see them on here, now.
Many thanks - I do a lot of macro work and like to get whatever I photograph IDd. I usually try to get the best photos I can technically, but also some other angles that may help with IDs if possible. I often don't know which "bits" are most significant, but wing veins are usually a good starter for flies, and random legs/ antennae often help. Of course the subject often buzzes off long before I get anything worthwhile in any sense!
Thanks both for the kind comments. You may be interested in a photo blog http://blog.2020v.org/2012/03/nickupton/unsung-heros-of-the-creepy-crawl... I did recently for a multimedia conservation project 2020VISION that I got some commissions for as a guest photographer. The blog is written for non specialists, but true invert fans may appreciate the sentiments too... It's a great project to be involved with and I've been doing bird photography for it as well - Cranes and wildfowl in Somerset and some urban bird life too. Photography is just a sideline at the moment, but I hope to keep building on what I've done so far.
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