jeremyr's picture

A grassland hoverfly

Observed: 29th August 2012 By: jeremyrjeremyr’s reputation in Invertebratesjeremyr’s reputation in Invertebratesjeremyr’s reputation in Invertebratesjeremyr’s reputation in Invertebratesjeremyr’s reputation in Invertebrates
pedissequum1
pedissequum3
pedissequum2
pedissequum4
pedissequum5
stackelbergi
Description:

Having not seen two of this genus closer to each other than a hundred yards, there were 5 in this short 50 yard stretch, with a pair, one quite small, together on a small plant. No net, this sat still as the small tube was popped over it, so it could be checked. Not suspect in any way it was then released.
So far I've only found this species in urban parks. As usual there were several Ectemnius Digger wasps about, I can only really tell the difference if they fly close to the ground or close enough to see the wasp's big square head. Very low down the wasp bobs more in it's flight or might lurch suddenly and the fly hover-drifts more. Plus the fly will wander off into the grass while Ectemnius seems to stay closer to its log haunts. Once settled all similarities are gone.

Identifications
Species interactions

No interactions present.

Comments

Wildlife Ranger's picture

Xanth

Good sequence well thought thru

WLR

ophrys's picture

Xanthogramma

Like Roger, I was not exactly sure at first whether the captions referred to each column or just the final two photos. I assumed the latter, which is why I agreed with pedissequum for the first 4 pictures.

Xanthogramma sp. is probably safest, I suppose, when the experts are still working out the key features for these in this country.

Ian
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My Flickr photos...

http://www.flickr.com/photos/52163027@N02/

jeremyr's picture

pics

Pictures 1-5 are the observation, picture 6 is there to compare with picture 5. All the pictures are titled with their species, perhaps the labelling of the lower pictures gives the impression that they're columns, so I'll redo it

The purpose of the comparison was to show the sternites, not generally photographed in iSpot observations of this genus. In fact picture 2 appears to have all three of the id features used

Apologies for the confusion, I see too that the glassed specimens reinforce that impression

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ophrys's picture

Photos

It is a really great series of photos and good to have each one labelled. iSpot is amassing a really good series of photos of many hoverflies, though usually just the commoner species, I suppose (though not common in this case!).

Ian
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My Flickr photos...

http://www.flickr.com/photos/52163027@N02/

Wildlife Ranger's picture

Xanthogramma

I think its clear that observation you are fielding is Xanthogramma pedissequum and that you are comparing in the final shot X. Stackelbergi which is not well defined in the literature I have no trouble in agreing with X. pedissequum since that is presumably what you posted !! and I can see enough from Stubbs to support the ob on pedissequum

WLR

jeremyr's picture

stackelbergi

here's a link to X.stackelbergi with further comparisons of the traditional features that are easily visible http://www.ispot.org.uk/node/287866

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