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Looking at Adonis blues this afternoon nearly half had some form of malformation or aberration; what's going on? It was a veritable freak show.

I've been looking at my Butterflies of Britain and Ireland and it doesn't really give me much information.

Looking at the individuals, I had wondered whether this might be due to some physical disturbance of the area near to emergence time, causing physical damage to pupae and perhaps inducing some to emerge early, before the full colouration had been reached (emerging early in the sense of 'escaping' whatever the physical disturbance might have been).

Pure uneducated speculation, but that's what was going through my mind, looking at the pictures.

Guy

I came across this picture yesterday which shows the phenomenon quite nicely - http://www.flickr.com/photos/42851970@N ... 519997@N00
There seem to be a lot of ab. krodeli butterflies around, I don't know anything about the causes of this aberration but I think that perhaps it may have been brought on by the extended period of hot, dry weather in April when they were pupating. Out of interest all the ab. krodeli butterflies that I've seen (only 5 or 6, and only ever in the second brood) have been crippled in some way, so I suppose that the same conditions that lead to the aberration are also detrimental to the butterfly's development.
Those are just my thoughts though, I'd be very interested to hear why this is going on too!
Guy

If this is normally only seen in the Summer emergence, and yet this year they are appearing now, it seems likely this is weather related. I would guess the ground temperatures during pupation this year were much higher than normal, and might well have reached the levels of a warm spell in July (far less vegetation cover in Spring to diffuse the sun's heat). An exceptional April has caused all kinds of unusual butterfly events - this may well be just another example.

Dave

I think it must be due to the extremely hot April we've had, as mentioned above other posters. There are just so many affected I don't think it is likely to be ground disturbance.

I've been so intrigued by this whole business I've just got back from going to the site again this evening. I've never been butterflying in the evening before and it was a revelation (but that's another story). To see all the blues hanging up just convinced me just how many were aberrants. It's not half but it is possibly a quarter which aren't normal and that's just to my untrained eye.

From reading the info about the adonis blues on this site species info it seems as if the majority of the abs are krodeli and nigrescens.

I am extremely concerned for the summer brood. The ground is crunchy in places because the vegetation is so dry.

Susie wrote:I am extremely concerned for the summer brood. The ground is crunchy in places because the vegetation is so dry.

Yes - What if all the useable Horseshoe Vetch has been munched by the Chalkhill caterpillars?

Counting the roosting butterflies was a good way of accurately estimating the number of deformed Adonis. Did you happen to see anything unusual in the Common Blues Or Brown Argus? My only observation from last weekend is that there were very few of the former, and that some of the latter were particularly small.

Dave

The brown argus all seemed fine, albeit tiny.

I think the common blues seemed okay, some of what I thought were common blues because they were small I now think are adonis. My idea skills aren't the best so trying to identify something which doesn't look as it should anyway is ever so tricky for me!

Here is the freakiest from this evening. It reminds me of the butterfly equivalent of a hound from hell with it's hairless and sleak black body.

Poor little thing. Did you notice how many were male and how many female? I got the impression that they were all male, but your photo of the mating pair shows the female with the aberrant markings, I think.

Dave

There were lots of females, but far more males.

This one was small, but apart from that it seemed to be able to function okay. The opposite wing, which I didn't get a chance to photograph, had some faint spotting on it. I think it is ab. nigrascens.

There was another one this afternoon with a similar body but far more normal wings. She seemed to be interested in egg laying so I took a couple of snaps and left her to it.

Another female aberration.

Recipe: bake butterfly in a hot ant hill, gas mark 6 for a month, turn out when crispy and allow to cool.

Susie wrote:I am extremely concerned for the summer brood. The ground is crunchy in places because the vegetation is so dry.

You're right to be concerned. The signs are that (on certain sites) the population could crash significantly as a result of the drought. The adonis blue is highly susceptible to dessication of food plant in this country and will suffer badly in drought conditions. A quick glance at the 1977 data for this species following the drought of 1976 illustrates this well.

Regarding coridon larvae eating all the adonis foodplant; although there is an overlap in habitat preferences, the chalkhill larvae prefer a slightly different micro-climate in which to develop and therefore chalkhill blue larvae will not impact the amount of available suitable food for adonis blues. Nature's good like that.

It does remind me of a small population of silver studded blue that I used to regularly monitor however, where one year there was an unexpected explosion in burnet moths. Even as the blues were flying, the burnet moth larvae in their thousands were consuming a huge percentage of the larval food plant, decimating the place would be a more accurate description; and sure enough the blues crashed badly (as did the burnets through eventual larval starvation after having consumed all the available foodplant leaving only the most advanced larvae able to complete their development). But I digress...

Depending upon weather conditions from here on, the adonis blue, which has enjoyed favourable breeding conditions for several years now, could well take a bit of a hit.

Of course, what is detrimental to one species is highly beneficial to another, and the few calcareous grass land populations of grayling left in the south of England are set for a great year having benefited hugely from the warm, dry, spring.

Felix.

I have just come back from my first ever visit to Denbies Hillside. Why have I not been there before , it's only 25 miles from my house.

I went mainly to get some photos of aberrant Adonis Blues and I was not disappointed. They were not around in great numbers, but I managed to find some fresh individuals, one of which was very odd indeed. From the upperside it looked like a normal male, albeit with slightly crumpled hind wings. There were however many spots missing from the underside and then I realised that the left and right undersides were different from each other.
That's all I have time to post at the moment, but may have some others later.

Vince

It's an amazing place at the moment, Vince, isn't it?!

Not only are the left and right wings different but the fore and hind wings are a different colour too. It's a corker.

I wonder if the forewings being paler have anything to do with a chalkhill blue influence? Could this be a result of cross breeding as well as/instead of environmental factors?

Where's Felix when you need him.

There were a few similar aberrant Chalkhill Blues at Denbies last summer, but no Adonis that I can recall. If there is a common environmental factor, I do recall a very dry and warm spell during June last year, during the time the Chalkhills would have been in the pupal stage.

Dave

Thx for the tipoff Susie - I visited Denbies today and was absolutely amazed! Report in my personal diary at:

viewtopic.php?f=29&t=3977&p=45012#p45012

Cheers,

- Pete

Have there been any reports of similar aberrations from other Adonis sites? Mill Hill near Shoreham is a frequently visited spot, for example. It may be that the rainfall pattern over Southern England would show Denbies as particularly lacking in rain compared to elsewhere. If there were a genetic factor, would it not have cropped up before from time to time? It's not something I've noticed in either brood of Adonis over the last three summers (2008-10).

The emergence this year is certainly much larger in numbers this year I think. Susie, as another regular visitor, may wish to comment here.

Dave

You are very welcome, Pete.

I am afraid that I have no real idea as to average numbers of spring adonis on this site, Dave, even though for the past couple of years I have tried to visit weekly from the start of May until August. I do know that I usually see really good numbers of adonis blues at this site and this year doesn't seem to be exceptional to me in numbers other than numbers of oddities which really are remarkable.

I wonder if the situation at Denbies has been picked up by the people at Surrey Butterfly Conservation and what data they have on this site, yearly numbers of adonis seen and what percentage of the population tends to be aberrant? I assume (hope) that someone does a transect at this site?

Perhaps I am making too much of a big deal of this but I really do feel that there is something going on here which is of interest and more research should be done into it. I am just not sure who to contact about it (other than you good people, of course!).

millerd wrote:Have there been any reports of similar aberrations from other Adonis sites? Mill Hill near Shoreham is a frequently visited spot, for example.

Kipper, can you help on this, what is happening elsewhere in Sussex?

Susie wrote:I wonder if the situation at Denbies has been picked up by the people at Surrey Butterfly Conservation and what data they have on this site, yearly numbers of adonis seen and what percentage of the population tends to be aberrant? I assume (hope) that someone does a transect at this site?

Hi Susie,

Denbies most certainly does have ongoing transect data. Get in touch with Richard Donovan (transect co-ordinator for Surrey/SW London BC) at rdonovan@surreybutterflies.org or chat to David Gardner (Chairman) although he may well bend your ear for longer than anticipated. Best to stick to email lol!
He's at dgardner@surreybutterflies.org

Cheers,

Gibster.

Thanks Gibster