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#1 2008-03-03 12:30:31

Rainieria
Committee
Name: Darwyn Sumner
Registered: 2008-02-20
Posts: 384
Website

Loxocera: take to Preston Montford

I've been trying to make my key more intelligible and several people are having problems.
If you bring along specimens to Preston Montford this week we might have a chance to sort this out once and for all.


Darwyn Sumner
DF Bulletin Editor, Scheme Organiser: Stilt & Stalk Flies

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#2 2008-03-04 22:07:10

conopid
DF Members
Name: Nigel Jones
From: Shrewsbury
Registered: 2008-02-27
Posts: 701
Website

Re: Loxocera: take to Preston Montford

Hi Darwin,
I have several (all appear to be the same species). Will bring them along.


Nigel Jones
Shropshire

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#3 2008-04-02 00:51:44

Rainieria
Committee
Name: Darwyn Sumner
Registered: 2008-02-20
Posts: 384
Website

Re: Loxocera: take to Preston Montford

We have an outcome (of sorts).
First of all many thanks to those who brought specimens to our Tachinidae workshop (Malcolm, Nigel & the Ismays). Mid way through the second day, after having had a good shot at the Tachinidae, I gathered together all the specimens (40 or more) and tried to make sense of them.
There are 5 UK species and we had specimens of 4 of them on the day (see Checklist which I'll do later)
The following characters served well to separate the 4 species without recourse to my confusing earlier attempts at a key:

Loxocera sylvatica:
Frons - (dorsal surface of head) black with triangular yellow (a yellow which may be darkened to a dark brown) markings extending posteriorly from a wide base at the level of the antennae to an apex just short of the ocellar triangle, these triangular markings do not meet the eye margins.
Head profile - black in the top half, yellow in the lower half.
Face (below antennae) - Mainly yellow with black extending down as diffuse stripes along the margins of the eyes, ending at the lowest point of the eye; a broad brown central band.
Humeri - yellow

Loxocera albiseta:
Frons - (dorsal surface of head) black with triangular orange markings extending posteriorly from a wide base at the level of the antennae to an apex just beyond the ocellar triangle, these triangular markings do not meet the eye margins and may be interrupted by a diffuse black band stretching from eye to eye at a distance approximately 1/6th of the distance between the antennae and the ocellar triangle
Head profile - black in the top half, yellow in the lower half, postgenal hairs comprising only a small triangular patch of short white hairs
Face (below antennae) - Yellow, a broad yellow central band.
Humeri - black

Loxocera fulviventris:
Head profile - black except for a large, round yellow patch below the eye
Face (below antennae) - Mainly black with yellow around the mouth opening which extend as small patches up from the sides of the mouth opening; a broad black central band.
Humeri - black

Loxocera aristata:
Frons - (dorsal surface of head) black, may have a small dark orange spot anterior to the ocellar triangle
Head profile - black except for a small yellow patch below and adjoining the eye; adjoining this patch posteriorly and running from the eye to the mouth is a "shimmering stripe" (view obliquely from behind) comprising white hairs (which exhibit a good deal of variation in size in the specimens examined, ranging from just a shimmer hinting of white hairs to fairly long, clearly defined white hairs) I'm going to try for the term "postgenal stripe" for this feature
Face (below antennae) - Black
Humeri - black

One general observation from the meeting was that there was a good deal of variability in antennae and aristae lengths (after Lyneborg's key) with very different arista/antennae length ratios seen even on the same specimen. A more recent key exists, I have not seen it.

From the above characters it would seem that a first feature to examine is the colour of the humeri, followed by a check for the presence of a postgenal stripe. However there is other material to be examined.
I would be grateful for responses from any Loxocera-owners reading this who might be able to rephrase, amend or confirm my descriptions and add to the list of species thus described (European species only, please but especially the UK's L.nigrifrons)

There are incorrect records on the NBN Gateway - could all those sending me records in the past please resubmit them after checking.

Last edited by Rainieria (2008-04-02 00:54:09)


Darwyn Sumner
DF Bulletin Editor, Scheme Organiser: Stilt & Stalk Flies

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#4 2008-04-02 11:28:13

Rainieria
Committee
Name: Darwyn Sumner
Registered: 2008-02-20
Posts: 384
Website

Re: Loxocera: take to Preston Montford

The latest work on the Loxocera is:
Goot, Van Der. V.S., Veen, M.P.. 1996 De spillebeenvliegen, wortelvliegen en wolzwevers van Noordwest-Europa. Second edition.
Jeugdbondsuitgeverij, Utrecht, 57 pp.. . . . .90-5107-002-0 [Dutch].

I don't have this but the impression I have from Ben Hamers postings on Diptera.info is that they are very well described in the article.

The earlier paper I had been working from and from which I constructed (badly) the key I'd used in Dipterists Forum workshops was:
Lyneborg, A.L.. 1964 Danske acalyptrate fluer. 2.. Entomologiske Meddelelser. XXXII p.367-388 . . [Danish].

A copy of the Goot/Veen article would be much appreciated by yours truly.

Last edited by Rainieria (2008-04-02 11:28:39)


Darwyn Sumner
DF Bulletin Editor, Scheme Organiser: Stilt & Stalk Flies

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#5 2016-01-20 16:58:58

Rainieria
Committee
Name: Darwyn Sumner
Registered: 2008-02-20
Posts: 384
Website

Re: Loxocera: take to Preston Montford

The debate continued on Diptera.info at http://www.diptera.info/forum/viewthrea … d_id=62718
Just discovered this today.


Darwyn Sumner
DF Bulletin Editor, Scheme Organiser: Stilt & Stalk Flies

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