Which Small White?

[bugboy]

Hi, can I get some expert eye's on this chap please, found at Newhaven Tidemills today. In flight the wing tip fooled me to think it was a Large White at first.

[millerd]

Hi Paul!

I'm going to have a go at this... I had a look at the underside shot and there is a quite noticeable fork in vein 7 of the forewing. I think this is supposed to be one of the distinguishing features, making this butterfly a male Small White.

(I'll just go and get my fire extinguisher as others queue up to shoot me down in flames... )

Cheers,

Dave

[bugboy]

Hi Paul!

I'm going to have a go at this... I had a look at the underside shot and there is a quite noticeable fork in vein 7 of the forewing. I think this is supposed to be one of the distinguishing features, making this butterfly a male Small White.

(I'll just go and get my fire extinguisher as others queue up to shoot me down in flames... )

Cheers,

Dave

I did notice that too however I remember reading somewhere that there's some doubt as to whether that's still true now....

[Roger Gibbons]

It is almost certainly rapae (Small) rather than mannii (Southern Small). Several reasons:

The upf apical mark is quite square in mannii.

The fw black spot of mannii is either flat or concave, rapae not.

The unh colour is pale yellow for mannii, more distinctly yellow for rapae.

The famed fork – nearly always true that rapae has a v7 fork and mannii does not. The key word is “nearly”. Here is a 100% rapae with no hint of a fork:
https://www.butterfliesoffrance.com/htm ... re_30May21_

And I believe there are examples of mannii with a very small fork.

Then there is the pointedness of the fw apex, also the spread of grey unh scales…

Roger

[bugboy]

It is almost certainly rapae (Small) rather than mannii (Southern Small). Several reasons:

The upf apical mark is quite square in mannii.

The fw black spot of mannii is either flat or concave, rapae not.

The unh colour is pale yellow for mannii, more distinctly yellow for rapae.

The famed fork – nearly always true that rapae has a v7 fork and mannii does not. The key word is “nearly”. Here is a 100% rapae with no hint of a fork:
https://www.butterfliesoffrance.com/htm ... re_30May21_

And I believe there are examples of mannii with a very small fork.

Then there is the pointedness of the fw apex, also the spread of grey unh scales…

Roger

Thank you Roger, it was always going to be a long shot, but I shall keep looking