Semi-spotless Gatekeeper

[firstrees]

The attached photo was taken at Gramborough Hill, Salthouse, north Norfolk on 3 August 2010.

Following inital enquiries, I now find that, in over 1700 specimens in the Museum of Natural History, there are NONE with the eyespot missing on ONE wing, but three with no eyespots on both wings- the ab. obsoletissima. Thank you, Geoff Martin.

I have now emailed the relevant museums in Paris, Madrid and Leiden to see if they have any comments.

[Michaeljf]

You can almost imagine the butterfly winking at you....

Or maybe you could call it 'Captain Birdseye' (for any of you that can remember the old version of the advert)...

[Dave McCormick]

Thats interesting alright, nice find. never seen aything like this before, however I have saw something (sort of) like this with a riband wave moth I saw a month back. One forwing upperside (its right one) had more black at the tip than the left forewing upperside which looked normal, looked like the black band colours had "run" like ink on paper if you put it in water.

You can almost imagine the butterfly winking at you....

Or maybe you could call it 'Captain Birdseye' (for any of you that can remember the old version of the advert)...

"eye, eye" captian!

[Padfield]

I've never seen anything like it. That's a very rare sighting indeed.

In the old days she would have been caught and pinned. Isn't photography wonderful?

Guy

[Pete Eeles]

I've never seen anything like it. That's a very rare sighting indeed.

In the old days she would have been caught and pinned. Isn't photography wonderful?

Guy

I agree on all counts - especially with regard to photography!

The asymmetry is really quite something - and spectacularly unusual.

Cheers,

- Pete

[David M]

I've heard of butterflies being bilaterally gynandromorphic but I've never seen anything like this. Bizarre in the extreme.

[Piers]

Hi Firstrees,

The Gatekeeper is certainly an odd looking beast and probably very uncommon. I have seen similar aberrations in the Chalkhill Blue where one side is crippled and devoid of underside spots on one side only; similarly Small White where a malformed forewing lacked the apical black tip.

This prompted me to make a couple of enquiries and the general consensus seems to be that the 'spotless' wing is a result of the pupa not forming properly and the resulting butterfly also not being formed in the usual way; and looking at the image the left hand fore wing does seem to be slightly misshapen especially towards the apex.

Asymetric 'aberrations' are often caused by injury, damage, or a pathalogical condition of the larva or pupa which results in a malformed adult insect.

Usually however, deformed pupae produce crumpled adult butterflies which, despite their crumpled or dishevelled appearance, bear all the expected markings but on a misshapen insect. This is clearly not the case with your specimen though, and something significant must have occurred to upset the normal processes whereby the pigments develop during the pupal stage. In all likelihood the the disruption was pathological (ie caused by disease) or possibly an injury sustained by the larva, rather than simply damage to or malformation of the pupa, which normally explains deformed or crippled butterflies.

A diseased or crippled larva, or even a larva that had some genetic defect, could quite conceivably go on to pupate successfully and eventually produce a butterfly that was 'missing' some of the expected markings although otherwise healthy.

Felix.

[firstrees]

I have received the explanation below, regarding my Semi-spotless Gatekeeper at Salthouse last August. Bernard Watts, who wrote it, has given me permission to post it, as he is completely bound up with his magnum opus on European butterflies:

“I think the reason for the absent spot is clear: there has been physical damage to the wing proximal to the eye-spot position.

The effect of this on the wing-margin is clear and the effect on the venation in the region of the eye-spot position is also visible.

Thus the insect, though interesting, is merely damaged! i.e. not an aberration in the usual sense.

For such damage to have an effect on wing-pattern, it usually has to happen in the first day or so of pupation.

If one looks carefully, one can see two small pale marks near the costa of each left-hand wing. When the wings were folded in the pupa these would presumable have been aligned. This suggests a wasp, say, pierced the pupa twice just after formation and probably actually struck a vein.”

This has now been published in the N&NNS’s ‘Natterjack’ quarterly.

[Piers]

Do you not bother to read the replies to the questions that you post on this forum Firstrees?

FFS.

Felix.

[NickB]

Down, Felix!
Give the guy a break; he is simply relating what else he has been told.....
I don't think anything else was implied....