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Pieris

Posted: Mon May 31, 2021 10:43 am
by Roger Gibbons
Anyone like to identify this?
Pieris.JPG
Roger

Re: Pieris

Posted: Mon May 31, 2021 11:59 am
by Mikhail
If I was on holiday in Bulgaria I'd say mannii. I'm just a little unsure of that forewing discal spot. Over to the experts....

M

Re: Pieris

Posted: Mon May 31, 2021 12:49 pm
by Padfield
I agree it has a lot of mannii about it - including the disputed absence of a fork in v.7 (though there is a hint of a fork at just the right place in this picture). I'm a little worried by the seeming lack of marginal dark scaling down the outer margin of the forewing upperside. What can be seen of this wing surface doesn't look like mannii. The even, dark scaling of the underside hindwing is good but spring rapae can be quite similar:

Image
(rapae, this May)

If this was seen in the UK, I'd be obliged to say it was rapae. If in France, in a known region for mannii, it could be a slightly anomalous mannii. If you're somewhere else, Roger, you lucky man! I've been grounded for months ...

Guy

Re: Pieris

Posted: Mon May 31, 2021 7:28 pm
by bugboy
Just to stick my tuppence in, although I've never seen a mannii. I have noticed this year practically every Small White I've got close enough to, to get a decent look, has much heavier dusting than I usually see on the underside hindwings to the point I've had a few heart stopping moments until I've seen the uppers.
Small White female, Walthamstow Marshes.JPG

Re: Pieris

Posted: Tue Jun 01, 2021 10:59 am
by Roger Gibbons
Thanks Mikhail, Guy and Bugboy for your responses.

It probably added to the mystique that I might have been in France (as would normally be the case at this time of year) or in the UK. It was, in fact, taken a few days ago in Hatfield.

I saw the upperside (and have a photo) so there is no possibility that it could be mannii.

The reason for posting is that the oft-stated means of separating rapae and mannii could lead to the wrong conclusion here, especially if only an underside view had been possible.

1. vein 7 of the forewing is clearly not forked, which is usually quoted as the key differentiator and indicative of mannii (although, to be fair to Lafranchis, he says rapae “often forked”).

2. the unh dusting of grey scales: it is often quoted that this dusting is broadly across the whole hindwing in mannii, but in rapae it is mainly below the cell. Lafranchis says this, without qualification.

However, these two key clues would lead you to the wrong conclusion if you only took these into consideration. Bugboy’s photo looks very similar.

Mikhail’s comment about the discal spot is very pertinent. In my experience it is always either straight-edge or concave externally for mannii, and this one clearly isn’t.

As there have been a number of putative sightings of mannii as the hope that it might reach these shores (at least in some quarters) has become quite febrile, it just illustrates that both surfaces need to be seen in order to be sure.

Roger