RECORDS Syrphid (Hover) flies for ID

[JRsbugs]

Sericomyia silentis male and female.

This is the second year I have seen this, both times on Ivy in October but last year I only saw the female.

Male on 1st October, female on 12th October 2009, she landed on a shrub next to the Ivy.

Female


Male

[JRsbugs]

Skipping Sphaerophoria until I sort them better, I may have a different one or two.

Syritta pipiens, male and female.

First female for this year on 25th April. First male on 28th May. Last sighting a male on Ivy on 18th September 2009.

Females


Males

[Jason Green]

Hi Janet,

The collection's coming on well, I love the second pipiens by the way - it shows the distinctive hind femora well

As for Sphaerophoria spp. - forget it unless you have a microscope and the will to do some dissection! Yes, you get individuals with aesthetic differences particularly on the final tergite, but these aren't reliable

[JRsbugs]

Originally Posted by Jason Green

Hi Janet,

The collection's coming on well, I love the second pipiens by the way - it shows the distinctive hind femora well

As for Sphaerophoria spp. - forget it unless you have a microscope and the will to do some dissection! Yes, you get individuals with aesthetic differences particularly on the final tergite, but these aren't reliable

Thanks Jason. I do know Sphaerophoria are difficult or impossible, but some of the experts often have little tricks up their sleeves we don't know about. I intend to pick their brains just in case.

[Jason Green]

Well, let me know if you do! I doubt there are though, and I dare say that for records to be accepted in the UK at least it probably needs dissection since all British work is based on genetalia

Speaking of dissection, I was going through the FSC key to slugs - and said some need opening up to determine species. I mean, can you imagine cutting into a dead slug in full stereomicroscopic beauty at 20x?!

[JRsbugs]

Maybe dissection is required for most males, but females of the more common species I think are different.

Dissecting a slug is not at the top of my list of things I want to do.

[aeshna5]

Originally Posted by JRsbugs

Maybe dissection is required for most males, but females of the more common species I think are different.

Dissecting a slug is not at the top of my list of things I want to do.

I thought the females did need dissection + that it was only male S. scripta that could be easily done in the field.

[Jason Green]

Originally Posted by aeshna5

I thought the females did need dissection + that it was only male S. scripta that could be easily done in the field.

Pretty sure that's correct! I don't think records could be accepted without, and that keys would really require an individual and a microscope - I doubt it means photos would do. A male scripta can be identified by wing length - they're pretty short apparently, and so if you have a male with long wings it's one of the other 12 or so in the group.

[JRsbugs]

Originally Posted by Jason Green

Pretty sure that's correct! I don't think records could be accepted without, and that keys would really require an individual and a microscope - I doubt it means photos would do. A male scripta can be identified by wing length - they're pretty short apparently, and so if you have a male with long wings it's one of the other 12 or so in the group.

I'm looking more for probables than positive ID's, but I do think some can be positively identified. There are certain points to look for, based on collections although it's not necessarily 100% there are people who know the differences between some species. Whether or not I get a positive ID on any, all I intend to do is give a probability then it's up to a recorder whether or not they want to take it as a record.

Males don't necessarily need dissection either, just a pinned specimen where the genital needs to be only upturned.

[JRsbugs]

Syrphus ribesii female.

I didn't get a pic of what I could say for sure was a male this year. There are 4 species which are similar, males are difficult if not impossible to separate without a specimen. Male S. ribesii can be identified by the hind femora, which can be either all yellow or black on the basal 2/3 but the latter can de difficult to separate from S. vitripennis and S. rectus. The other, S. torvus can be identified by hairs on the eyes but it seems others can have a few hairs too.

Female S. ribesii are easier, with all yellow hind femora or black only at the base. The shapes on the abdomen are usually complete on tergites 3 & 4 but can be slightly divided, and are variable in shape.