A Field Study and Photographic Examination of The Blue Female of the Common Blue in Bradford and some other parts of West Yorks. To be continued...


By: Stuart and David Wise. Spring 2002.


     This text is a combination of conjecture, facts and photographs. It highlights, in particular, slight variations and the different types of  habitat on which the Common Blue can be found  in and around Bradford and some other areas of West Yorks. The variations are, for the most part, restricted to the females and over the past few years we have become aware of the spread of the bluish or blue female here. Quite possibly there exists in the area, a gradient going from the 'normal' icarus forms of the female through to the ab. mariscolore. However, there are, for sure, many and varied inter-grades.


Shipley Stn Wrose Hill
Above: Shipley Station Meadow & blue female. June 2001 Above:  Male Common Blue. Quarry on Wrose Brow. Bradford, June 2001


Of the British Lycaenidae, the Common Blue is easily the most variable now. Just two decades ago and the prize would have gone to the Adonis and Chalkhill Blue. We may be witnessing a rare instance of selection and adaptation - certainly change - occurring in a widespread animal population within the space of a person's lifetime. Though females are effected the most, the male is not wholly immune and one can detect a hint of discal spotting or scaling where under wing markings show through to an extent we have not previously noted. (see elsewhere photo of Brockadale specimen). Whether this indicates a thinning of the upper side wing scaling  or a more pronounced under side markings is in doubt. However, we have noted it in newly emerged specimens as well as dished specimens that are more denuded of scales.

      The Bradford area looks particularly unusual in the number of variations encountered. Some colonies of the butterfly are more varied than others. On Shipley Station Meadow, for example, females possessing, to varying degrees, a bluish blush, massively outweighs the normal female in the Bradford area though Ms Susan Stead assures us she saw one in the year 2000 on Shipley Station Meadow and that they tend to predominate in Trench Meadows some distance away.

      However, this does not alter the fact that in many colonies in and around Bradford, the normal form has ceased to be dominant and become recessive. We must have been half asleep not to have paid attention to its disappearance or virtual disappearance, previously. It could be the gene or genes coding for the normal female have become - or are becoming - lost in the Bradford Common Blue populations.

     Of all the Common Blue sites presently known in the Bradford area, the one at Raw Nook (Low Moor) is the most variable. The percentage of brownish to blue females though has yet to be established as does the percentage of females showing varying degrees of white scaling around the black discal spots on the upper and lower wings. These characteristics can also be found elsewhere in Bradford particularly on Wrose Brow quarries. Though the degree of diversity at Raw Nook is unmatched elsewhere, there surely can be next to no interchange with those colonies on the other side of Bradford i.e. like Wrose Brow, Shipley Station Meadow or, Baildon Green etc. There is a more typical form of the Common Blue female at Raw Nook, except it has discal spotting on all four upper side wings. If the background colour changes from dark chocolate brown to blue, one has the variety reproduced here (see photos) from Healey Mills marshalling yards, Ossett/Horbury. That there maybe some interchange between Raw Nook and Healey Mills is more likely as there is no formidable barrier like Bradford City in the way. Again, at Wrose Brow, on the far side of the city, there are females on which rather indefinite 'soft focus' spots appear (c/f photo ) but nothing like as pronounced as in Raw Nook.

     Finally, there is the quite remarkable blue female photographed on Shipley Station Meadow (see below) in which altogether one can count eight spots with a clearly defined discal spot with a central black dot on the upper wings.


Shipley Common Blue Common Blue
Blue female variant; north west vector of Shipley station triangle, June 24th 2000. It was a cold dark day with fitful sunshine. On the original photo there were altogether eight spots or flashes with just a hint of a black dot in the centre of the discal spot on the lower wing. The same blue female close up which unfortunately doesn't show the spotting in a clearer way. Colour scanning and reproduction has reduced visibility. However, compare with those from Wrose Brow which overlooks Shipley Station and the specimen from Healey Mills reproduced on this web page.

     It is possible that minor individual variations amongst the females are more likely to be found in particular geographic areas and may even be restricted to them and there is some suggestion of this in the following photographic analysis. However, this will really mean more painstaking research and require the taking of hundreds of close-up shots that highlights taxonomic characteristics rather than showing the butterfly in various and even unusual habitats like, for example, nectaring on heather in Raw Nook.

     Previously, the blue female would sometimes be referred to as the Irish blue because it tended to be restricted to Ireland and Scotland. Certainly, the most outstanding examples we have seen came from Co Tyrone and were caught by Porritt in the 19th century and now form part of his justly famous collection in the Tolson Museum in Huddersfield. Interestingly, in neither the Porritt or Morley collection we do not recall seeing any blue female from neighbouring vicinities in West Yorks. A word of caution though is necessary. Some Lepidopterists make a distinction between the blue female and ab.mariscolare; the Irish blue. Thomas and Lewington abide by this distinction, pointing out that the latter is sometimes regarded as,  'a distinct sub species,' being rather larger than southern English specimens, possessing orange lunules, 'almost forming into a band.' Indeed, the butterfly is so striking it's been mistaken for Large and Adonis Blue! Lewington's illustrations reinforce this distinction. On the other hand, Richard South, a lepidopterist fascinated by aberration, in the  early years of the 20th century, makes no such distinction. Heath/Emmett more cautiously draw a distinction adding that ab. mariscolore occurs in England though infrequently. We are inclined to the view an approximation exists.

        Consider the Brockadale, near Pontefract, West Yorks specimen photographed below on August 31st 2001.


Brock Maris Brock Maris

    (As one can see this is an exceptionally blue, blue female approximating in colour, though not in size, to The Irish Blue. Heath/Emmett claim that in the sub sp: mariscolare, the fore wing is slightly more acute as in this specimen. Also, the lunules are a larger and brighter orange. We would ask: is this butterfly present in significant numbers at Brockadale?)

    Whatever the precise taxonomic status, there does not appear to be much information (if any) on the spread of the blue female. Most books on British lepidoptera illustrating the male and female forms, only rarely give examples of the blue female and then without comment, apart from saying it's more of a northern than southern phenomena. In the 1989 update of The Observers book of Butterflies by Paul Morrison, in place of the former brown female Common Blue there is an illustration of the increasingly typical blue female..

     Previously restricted to more northern climes, its spread southwards suggests there are more important factors than climate at work. That there is a major change taking place  cannot be doubted and so far we are all in the dark as to the reason why. And this dramatic spread has taken place, so it seems, within the last three decades.

     If climate had anything to do with it we could have expected this variation to retreat even further north: instead it is becoming more common in the south. We were rather surprised in August 2000, to find a quite pronounced example of the blue female in Brompton Road cemetery in Chelsea, West London. Unfortunately, we were unable to procure a photo. However, so far we have not chanced on it in the countryside immediately to the north and south of London. Instead on Ranmore Common on the North Downs, we have noted on a number of occasions, dwarf specimens of the typical form of the Common Blue female. They seem to be present in sufficient numbers for this phenomenon to be statistically significant and not a mere freak. Again, we don't know the ratio, except that it is not at all unusual on Ranmore Common. On Ranmore Common there can be a confusion of Blues - indeed they can teem - and the smaller size possibly helps in identifying the butterfly: not only to us but also perhaps, to the male Common Blue which appear not to be deterred in the slightest by the female's dwarf proportions. Ms Susan Stead claims that normal forms of the female in the Bradford area are smaller than the blue females and this observation bears out what other Lepidopterists have maintained. But whether they are dwarfs like on Ranmore Common has yet to be determined. Seeing how difficult it is to quickly distinguish between female Common Blues and female Chalkhill and Adonis Blues, one would have thought Lycaenidae hot spots like this would be conducive to a drastic change in colouration. But no such thing. In fact, the change has occurred in areas and on terrain where the Common Blue flies unchallenged by any other Blue species. However, in the north of England we have not come across this unusual phenomenon though we did find a dwarf male in Gaisby quarries, Bradford (see photo elsewhere). The latter may have been a freak or, a case of accelerated development, as the site is particularly high and exposed.

       One may indeed wonder if the dangers of hybridization are all that acute between species that bear a close resemblance to each other. Just how much time is lost by males pursuing a promising looking female only to be cruelly disappointed at the last moment? And exactly what are the mechanisms that stimulate a male's interest in the first place' Colour must surely play an important role and if males are now becoming progressively more excited by blue than brown it does indicate a huge upheaval in the pattern of stimulus and response. In parenthesis, we would add that it was the lack of interest shown by pristine blue males to what we thought were ragged, though slightly smaller, typical females on the Brockadale YNU site near Pontefract that led us to the discovery of the Brown Argus.

      Where two morphs are as dissimilar as the normal and the blue female, inevitably problems are posed for our understanding of the signalling system between male and female. Just what does attract the male to the female over distances? Is it wing movement or colour (or a subtle combination of both when displaying) as the band of orange lunules, it seems, will only be visible close to?  Significantly, the blue of the blue female is not quite the same as that of the male and is of an almost cerulean, purplish tint. This slight difference may make all the difference in the world to this apparent cross dresser of a butterfly which may not gender bend to the degree we think. In any case, it is worth studying closely. Curiously, when a male Common Blue and blue female mate a tug of war ensues with both sexes struggling for dominance. First, boys on top then girls and vice versa. It's a ritual that creates the impression they're struggling to get free from each other. On one occasion in Shipley Station Meadow when the performance was over, both species opened their wings and faced each other almost as if saluting! (see sequence of photos elsewhere). We can maybe read too much into this behaviour as Common Blues find it convenient to close their wings when mating. It also provides more effective camouflage and opening their wings in the sunshine is therefore, simply a reflex.

       Doubtless, there are many more Common Blue colonies in the Bradford area and West Yorkshire as a whole that are still unknown. As yet, it is not possible to say much beyond these colonies will, most likely, be host to a bewildering array of varieties. Though not necessarily all that striking, quite a few of them may never have been illustrated or described.

     Though the blue female is on the march, possibly throughout Britain, it does not rule out the hypothesis that the extent of the variation we see in the Bradford area is a hangover from the paleo-industrial epoch. There is evidence to suggest that small colonies may have clung on in isolated, over-looked spots. Moreover, it is well known that small populations have a tendency to develop random peculiarities of their own. This became a bone of contention between the American geneticist Sewal-Wright and more orthodox evolutionists like the mathematical evolutionist, R A Fischer and E B Ford who stuck to the view nature was more rigourous in its operations and would rapidly weed out the maladapted. This clash of opinion and both completely logical though not necessarily true given the different presuppositions, was accompanied by a clash of equations. Central to the Ford/Fisher argument was the view that when an isolated population suddenly expands, variation increases until nature settles on the most suitable adaptation, ushering in a period of morphological stability.

     For all we know there may have been a sudden and dramatic increase in numbers of Common Blue in the past few years that could well explain the extent and range of variation. That variation will decrease rather than increase over the next few years is a very real possibility and for that reason it would be instructive to rigourously monitor population on a year by year basis. Even though it may not be possible to arrive at a convincing conclusion, a head count of different varieties on various sites over a number of years would not come amiss. It would, though, be a difficult and time-consuming task.

     E B Ford has, as per usual, interesting comments to make on the Common Blue. He maintains specimens can be arranged in a continuous series up to the wholly blue var. caerula Fuchs. If so, there must be in existence collections demonstrating this gradient. Ford also recorded (1945) a very distinctive race on Tean in the Scilly Isles in which the female is a pale silvery blue. Beyond noting that the species is not migratory with few insects making the journey to nearby islands (an observation which is of interest given the discreet nature of the Bradford colonies), he offers no clues as to why such a race might have evolved.

       Citing Ford's observations, Heath Emmett in The Butterflies of Britain and Ireland, say this characteristic favours the development of 'physiological races', a coinage that implies a degree of neutrality with little or no guiding selective pressure. On the question of variation, the book also says: 'Both sub-species' (i.e. the 'normal' icarus form and sub. sp. mariscolore) 'are subject to the same range of variation which is extensive, though less common than in Lycaenidae coridon or Lycaenidae bellargus'. As we have already said, bearing in mind the range of variation in the Bradford area, this assertion is no longer tenable though it is possible extreme variation (e.g. rayed forms) are more likely to be found among the Chalkhill and Adonis Blue. Ford is pretty much of the same opinion claiming, no doubt correctly for the 1940's; 'the butterfly is not subject to distinct geographical variation on the British mainland'.


      The Yorkshire Naturalists Union recently published in its quarterly journal, The Naturalist, a well researched and interesting text entitled: 'A century and a half of change in the butterfly fauna of the Huddersfield area of Yorkshire.'  (April/June 2001. Vol: 126. No 1037). It was particularly fascinating to us because as pre-teens growing up in the same area, and being precocious but innocent Lepidopterists, we had by the mid-50s and even earlier, noted the presence of the Common Blue and also, incidentally, the Meadow Brown, (the latter in considerable numbers). This was on Storrs Hill in Ossett overlooking the river Calder that flowed through Horbury below. Through the haze of smoke, which clung to the valley floor like a shroud, one could pick out Ravensthorpe, Mirfield and Huddersfield - just about. Storrs Hill was an abandoned quarry with a sheer rock face and piles of spoil heaps of varying heights, much of which was covered by sparse grasses. A natural attraction to kids, the place had a dream-like quality and was home to a colony of Common Blues which, from our recollection, were not restricted to any particular area and which surely must have numbered around 80 adults at the height of the flight period.

      However, we were supremely unaware that this was most unusual. All we do remember is that local working class kids were familiar with the butterfly naming it accurately and sparking in us, a life-long interest in butterflies and moths.

      The above mentioned YNU quarterly says; 'Polyommatus icarus certainly extended its range in the Huddersfield area from about the mid 20th century but whether the earliest stages of expansion were adequately recorded is uncertain.' How long, one wonders, had that colony on Storrs Hill been there? On account of its small town industrial situation, it could easily have been overlooked and Ossett, for sure, was not overrun with reliable Lepidopterists. But the fact that unschooled working class kids had no difficulty in naming the butterfly suggests that it had been there for some considerable length of time and that their parents must have passed on the information to them while out for a stroll.


Healey Blue  Healey Blue
   Healey Mills, Ossett, West Yorks. 1st July 2001. The specimen here shows a pronounced white scaling around the discal spots on the upper wings and a white scaling mark at the centre of the lower wings. possibly unique, more research is needed. R. South in 1906, assessing variation in the blue female, says: "The discal spot on the forewings may be encircled with bluish-white scales, and now and then this spot on all wings is surrounded very distinctly with bluish-white. I have seen the latter form from Durham and Ireland only, but it probably occurs in other parts."

       Documentation in and around Bradford is rather better and there is a record from Low Moor in 1936. As the YNU text adds: 'Bearing in mind the Wyke record of 1898 it is tempting to suggest that this persisted in the Wyke/Low Moor area just as it did around Skelmanthorpe.' Maybe the large numbers of Common Blue that are now found at Raw Nook has something to do with its former presence in Low Moor?

      Certainly in the late Summer of 2001, it does look as if the only examples of second generation Common Blue in the Bradford area were to be seen at Raw Nook where they were flying in gratifying numbers (see photos elsewhere). It is possible that a second-generation partial emergence is related - at least in the north - to the number of adults on the wing in the first generation and not so much on favourable weather conditions in late summer. There must be some reason for the discrepancy in the Bradford area where more suitable locations (e.g. Shipley Station Meadow) didn't produce a second brood.

       Conceivably the Storrs Hill population was founded by lone females blown across from the area east of Huddersfield, like Skelmanthorpe,  prior to the 1950s. As the NYU text says: 'Indeed it not only persisted but perhaps flourished in a restricted area in the east from at least the end of the 19th century'. It was very common near Skelmanthorpe in 1921, common in 1924 and 'not uncommon in a few stations in 1925 (Ben Morley 1922,1925,1926)'. It is not beyond the bounds of possibility that the butterfly led a covert existence on higher, less polluted, ground away from the valley floors where deposits of carbon and sulphurous gasses poisoned the vegetation and atmosphere and drew a smoke-blackened curtain across the sun on most days! For all we know, the Common Blue may have clung on during the paleo-industrial era in the sheltered and slightly elevated enclave of Baildon Green, Bradford, where there is an abundance of birds foot trefoil. Obviously, as its name suggests, it is ancient common land going back centuries and preceding the movement of enclosure. Even today, it's is grazed by horses and goats tethered to plug chains which ensures the grass is kept short and the dwarf bird's foot trefoil can thrive. These traditional grazing rights of the Green may well have thrown a lifeline to the Common Blue in the era of smoke-stack industry. Inevitably, this will always remain intelligent conjecture but Baildon Green may be north Bradford's  founding population.

      When we revisited Storrs Hill in Ossett in Summer 2001, after an absence of 46 years, we were delighted to find the Common Blue colony still there though much reduced in numbers. In fact, it was restricted to a very small area and we spent a good two hours searching for it on the abandoned heaps of quarried stones where formerly it flew in abundance. To hazard a guess, we reckoned that dirt track motorcycling had been the main culprit for the near destruction of this, possibly, historic site.

      Visiting Storrs Hill had been something of an after thought because our main purpose that day had been to check out the vast fields of birds foot trefoil in the disused parts of the freight marshalling yards of Healey Mills which runs from Horbury to Dewsbury.  Forty six years ago it was a filthy, evil-smelling dump of rusting boilers and suppurating batteries leaking PCB's into the soil. It is highly unlikely that in those distant days, the Common Blue was to be found here. Certainly, we never ever saw one on the scrub land descending from Storrs Hill to the marshalling yard though once we espied a Cinnabar moth. (At night though, a surprising number of moths were attracted to the yards' great arc lights. It is saddening to reflect that in spite of these supposedly much more ecologically rinsed times these once common experiences are becoming a thing of the past like watching a moth flying frenziedly around the bedroom).

       However, on this day in mid-summer, 2001, we were rewarded by any number of sightings and on a good year, the Common Blue might positively teem at Healey Mills. And teem they can do, as we once witnessed on the Chiltern Hills at Little Kimble.

         As previously mentioned and as shown elsewhere, we managed to photograph here a most unusual variety of the blue female  with distinct white scales surrounding the black spots on each of the upper side four wings. It was the most pronounced example of its type we had come across in West Yorks and maybe unique. In Brockadale, West Yorks, the Brown Argus has occasionally similar characteristics on its upper wings. This is known as ab: albiannulata though it seems there is no known Latin named equivalent for the Common Blue though Richard South mentions, perhaps somewhat ambiguously, the four white spots. As mentioned previously and as shown on page 9, we have noted approximations on other sites like for example on Wrose Brow quarries, Bradford. It is difficult, if not impossible, to say if the spotting increases the butterfly's chance of survival. It would, however, again be interesting to see if these minute variations are in West Yorks restricted geographically. If so, then it could be an example of the fine-tuning of adaptation.  On the other hand, the variations may have no significance whatsoever at the present time and only the far-flung future will determine in retrospect if they are part of a significant series. There must be countless examples of just such variations and all that can be said of them at present is that they are a vivid testimony to their plentitude.

     The failure in the aforementioned NYU text not to mention the increasing prevalence of the blue and, shades of blue, female, in the West Yorks areas, is a significant omission. However, in fairness, that wasn't the remit of the article.  However, we are both virtually certain that amongst the Common Blues we found in the 50s on Storrs Hill, there was not one blue female. As a counter-argument to the American geneticist, Sewell-Wright, we would say, the Storrs Hill Common Blue colony from 1952 to 1956 was a 'regular' population. Even at that early age, the fever for varieties, endemic among Lepidopterists, had gripped our young breasts. Of course, we preferred the electric blue males to the drab females and for that reason we would, in all likelihood, have enthusiastically lunged after a blue female.  Though Storrs Hill is now reduced to a colony of from 6 to 10 on the wing, the ratio of blue to typical female is now about 50/50. On the 1st of July, 2001, we noted a small typical female and interestingly, a male with a faint brownish flush wholly on the under wing costal margin.  Moreover, all the Common Blues seemed to be fractionally smaller than those in Healey Mills marshalling yards directly below Storrs Hill. Was this due to the dessicated, dwarfish, bird's foot trefoil' Nonetheless, we are all still in the dark as to the precise date this female made its appearance in this area, never mind the reasons behind such a major change. Maybe local collections should be more thoroughly scrutinised like Haxby's and Atkinson's now in the Leeds museum.  

       Originally, perhaps the Common Blue may have largely inhabited the lowland areas around Bradford. This would have been long, long ago before the advent of smokestack industries that were particularly harmful to indigenous insect populations. In order to survive, the Common Blue may have slowly moved up the hillsides where the air was rather cleaner, emissions lighter and freshly abandoned parts of quarries provided suitable terrain for the host plant, bird's foot trefoil, to take root. In 2001, we found flourishing 'new' sites on Wrose Hill and Wind Hill quarries and on the extensive terrain of Bolton Woods quarries. At the same time, Susan Stead found them flying on a previous Yorkshire Water site excavation in Eldwick, Bradford. All these discoveries tend to support the previous supposition.


Wrose Brow Wrose Brow  Wrose Brow
 Wrose Brow  Wrose Brow  Wrose Brow

  (Above: Wrose Brow, Bradford. July 14th 2001. Blue females predominate in this considerable colony and variation is greater than on Shipley Station Meadow ranging from a slight irroration to the almost totally blue. persistent winds stopped us obtaining a good photographic record. All specimens illustrated here show different variations. Note the vague spotting on upper and lower forewings numbering six on one specimen.)     

      From the mid 20th century onwards with the advent of various parliamentary clean air acts and the phasing out of coal fired energy and heat installations, the butterfly began to return to lower lands colonising the once busy goods yard of Shipley station triangle and the railway verges through to Bradford Foster Square. The butterfly also probably at the same time began to find suitable terrain along parts of canal embankments (e g, the Leeds/Liverpool canal adjacent to Charlestown etc).  In particular, the arid, partially tarmac surface area of Shipley Station triangle became just the type of industrially redundant  environment where bird's foot trefoil now thrived as it also did in the once bustling freight yard of Forster Square.

      In the early 1990s, the Common Blue could be seen flying here and fly tipping helped the bird's foot trefoil from being shaded out by grass. Alas, it was not to remain. A few years later, a dreadful retail supermarket development put paid to that. The combined banality of consumer consortiums, design and build firms and planners trampled all before it. It might still have been possible for the Common Blue to get itself a life here if, instead of the usual trimmed evergreen, pollutant-resistant, pastiche of nature (which insects abhor generally), builders rubble had been left for grasses, trefoil, St John's wort, ragwort etc to take root. It is possible, with growing ecological devastation this may one day be seen as a serious option. But we are a long way from this stage of recuperation of radical green currents. In fact today, it would be viewed as dereliction, an incitement to vandalism and worst of all, a disincentive to the real business of consumption.

       On top of this, Railtrack, in its fragmented madness, is equally zealous in its destruction of the rest of wild life as railway verges are regularly sprayed with ever more powerful herbicides often derivatives of the notorious roundup. Various sub-contracted, irresponsible firms who specialise in this 'nature cleansing' are given the go ahead by a Railtrack which doesn't know what the left or right hand is doing. Now, bird's foot trefoil has largely been eliminated along the railway track verge between Shipley Station and Bradford Forster Square. Odd patches still remain, particularly around Frizinghall and as a complement to the bio-diversity plan for the Common Blue in the Bradford Metropolitan area, a generous sowing of bird's foot trefoil seed by say, Bradford Council's  Countryside Commission, could do wonders in facilitating the spread of the Common Blue back into the city centre.

Some Experimental Suggestions
         At the risk of being repetitive, this possibly decisive change  occurring particularly amongst female Common Blues, must profoundly affect the signaling system that exists between males and females. Carefully conducted experiments could determine more accurately the role that colour plays in sexual attraction and whether it is primary or secondary to female pheromones as an attractant. Since Common Blues are not great travelers there may be an increased responsiveness by males to blue as opposed to brown and vice versa in local populations. By introducing a quota of brown females onto sites dominated by blue females, it may be possible to determine if the sexual appeal of both was equal or was heavily biased towards one form or the other ' 'assortative mating' in academic speak. (NB) On the Raw Nook site where blue and brown females appear to fly in equal numbers and where the amount of female variation is considerable, distinction would seem to break down. (However, this may fairly recently have been the case on Shipley Station Meadow).

Raw Nook Raw Nook
  Raw Nook, Low Moor, Bradford. September 14th 2001. A second generation of Common Blue emerged here that year though not, apparently, elsewhere in the Bradford area. It was not unusual to see the butterfly nectaring on the heather but generally the insects favoured the more typical thistles, ragwort and long grass. Opposite: The male and female have just mated. Above: Note the fly next to pronounced blue female.


      There is, interestingly, a variety of brown female in which there is not a hint of blue and therefore virtually indistinguishable from the Brown Argus. If it were possible to breed a pure line of these females they could be released onto a site and then kept under close observation to see how blue conditioned males responded to them. If the interest is obvious then it would indicate that the registration of and response to colour is not as important as it might appear to be.

      The first proper identification of a pheromone from the female silk moth, bombyx mori, was not established until the 1930's. Since then, there has been enormous strides in analysing the chemical make-up of pheromones (c/f The Natural History of Moths by Mark Young 1997). However, they are undoubtedly more important in moths and butterflies and as Malcolm J. Sable says in The Lepidoptera (1992): 'The entire subject of the role of pheromones, particularly in female butterflies, is uncertain ---- and besides visual clues are involved' (p.165). So for the moment, the balance of probabilities is that visual stimuli (colour and wing movement) is more important to day flying butterflies than scent.

The Butterfly of the Wind

        There is a little known book on butterflies called; 'Butterflies On My Mind'. Thinking back even from pre-teen days, we invariably associated the Common Blue with blue, windy days and waving grassland. Recalling the near total blackness of the map of Britain indicating the whereabouts of the Common Blue in Saunders' A Butterfly Book for the Pocket (1955), we are left in no doubt that it is the one lycaenid butterfly most adapted to the variable terrain and climate of this country. Of all the blues in Britain, the Common Blue is the one least phased by wind. In Gaisby/Bolton Woods Quarries, it could be found flying on top of the windswept plateau in the abandoned part of the quarry. In fact, it almost relishes the wind and its adaptation to this element could well constitute a factor in its survival. Often the butterfly prefers windy exposed spots to what seem ideal, sheltered conditions with a good covering of trefoil. Amongst all the other lycaenidae, it seems to have uniquely adapted itself to the wind. From observing the butterfly, this adaptation has, for the male, a territorial and display function and arouses the interest of the female, as well as being a very effective protective mechanism. The butterfly, particularly the male, is able to fly into a strong head wind and remain nearly stationary continuing all the while to flutter valiantly. Sometimes, it appears, to no purpose, at other times two or three centimetres in front of a female. Then, all of a sudden, it will let go, to be swept backwards in an arc by the wind, falling to the ground some thirty or forty feet away whereupon it seems to vanish. It is not a movement that willingly gives itself up to accurate observation by the human eye. A speeded-up visual recording of this manoeuvre could well show this fragile butterfly possessing extraordinary aerodynamic capacities (c/f following note on aviation). The wings of butterflies are evidently separated during flight unlike the wings on a moth which are coupled by a frenulum and retinaculum. In a following wind this should enable the Common Blue to lower its under wing or wings like the tail flap of a plane wing. Maybe a movie camera or a camcorder, where it is possible to stop each 'frame,' would reveal the secrets of this movement? It would not be easy to execute either and would involve running at top speed of 30mph or more across rough ground in tandem with the butterfly, carrying an unwieldy instrument which must remain focussed on the butterfly. (In truth, the task seems impossible!)

       The Common Blue's tendency to fly into the wind could also be a factor in the mating game and is used for display purposes and excitation before a resting female. Instead of displaying on an adjacent grass stalk, the butterfly furiously flaps its wings before yielding to the wind if the female does not return the interest. Again, it would be good to photograph the butterfly performing this particular manoeuvre possibly by using flash and a fast shutter speed.

A footnote on aviation, animal and human (S. Wise)
      From time to time, I have mused whether proto-aviators, like Leonardo Da Vinci, would not have been better off studying butterflies. Looking back, birds actually appear to have got in the way of an understanding of aerodynamics ' as also did a back-door anthropomorphism (angels had the wings of birds etc) because birds were vertebrates and not as totally unlike man as was the exoskeleton of a winged insect.

      True, a bird's wing approximates more closely to an aerofoil (i.e. a plane wing) with a convex upper surface and slightly concave underneath. But the ratio of wing to body size such as one finds in butterflies and the absence of a vertebrate muscular structure are closer to the mechanics of a heavier than air machine, at least in the early stage of the development of the airplane (e.g. the biplane). And butterflies were as capable of gliding as birds, especially the bigger, more showy, specimens.

      It does seem remarkable in retrospect that the kite was invented around 300 BC in China and yet it was only in the early years of the 20th century that powered flight was actually achieved. And what were the obstacles to the invention of the glider that should have preceded the invention of the powered airplane by many centuries? Surely the study of, for say, the venation of butterfly wings which have aerodynamic capacities like sail braces, could have led to a much earlier, rudimentary, form of air travel?

     In fact, the science of aerodynamics really only goes back to the mid-19th century and the flight experiments of the Yorkshireman, Charles Cayley. That otherwise superlative scientist and so much more besides, Leonardo, was on this issue, seduced by the obvious. The flapping wings of vertebrates had to be the key to the mastery of manned flight, the human body substituting for the fuselage exoskeleton.

     It is a mystery how this vast mind which was so quick to rend the veil of common sense and knew the sky was black not blue and that light rays were refracted through the earth's atmosphere, did not create the first wind tunnel. He could so easily have wafted smoke, with the aid of a fan of some kind, through a wooden barrel into which glass windows had been inserted so he was able to observe how the smoke, buffeted by air currents, reacted on various objects.


                                                                   Shipley Stn

 Blue Female at Shipley Station, Bradford, West Yorks, 2001 and photographed on the spare land adjacent to the Leeds/Morecambe line. This photo was part of the original pamphlet. In 1993 a big new waiting room was built which  seized (yet again!) some of this spare land. Much of the original vegetation was pulled up in construction and the butterfly population was decimated. Since then we have seeded  some of this area with birds foot trefoil and we await results. Most of our seeding though has taken place - beginning in 2001 - across the other side of the Leeds/Bradford Forster Square line so now there is a flourishing Common Blue population where they were previously absent. Interestingly, 150  yards  farther on and across the Bradford river (T' Mucky Beck) we put in a couple of birds foot trefoil plants on a piece of waste ground adjacent to an old factory. Within a single generation in May 2004 we saw a blue female reconnoitering even though the plants had not yet flowered! This was a colonisation occurring far faster than we ever could have imagined.