roland trimen and the 'merope' harem

Roland Trimen and the 'Merope' HaremAuthor(s): Alan CohenSource: Notes and Records of the Royal Society of London, Vol. 56, No. 2 (May, 2002), pp. 205-218Published by: The Royal SocietyStable URL: http://www.jstor.org/stable/3557668 .

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Notes Rec. R. Soc. Lond. 56 (2), 205-218 (2002) ? 2002 The Royal Society

ROLAND TRIMEN AND THE MEROPE HAREM

by

ALAN COHEN

42 Meadow Road, Pinner, Middlesex HA5 lED, UK

SUMMARY

Roland Trimen (1840-1916, ER.S. 1883) began to publish his entomological research in 1863. Although his main interest was in the taxonomy of South African butterflies he made important discoveries that helped to lay the foundations of the study of mimicry in insects. Together with Charles Darwin, Henry W. Bates, Alfred R. Wallace, Fritz Mfiller and Raphael Meldola he was one of those natural historians who may be credited with creating the science of ecology.

INTRODUCTION

Born in London in 1840, Roland Trimen (figure 1) was educated first at Rottingdean and then at King's College School in Wimbledon. His younger brother Henry (1843- 96, F.R.S. 1888) became a well-known and much respected botanist and physician. For many years Henry Trimen edited the Journal of Botany in London before being appointed Director of the Botanic Gardens at Peradeniya in Ceylon from 1879 until his early death in 1896. Roland claimed that his choice of career as an entomologist was determined as a schoolboy when he and his brother decided to be natural historians and drew lots as to which subject to study.

In 1858 Roland Trimen went to the Cape of Good Hope to improve his health, as he had been suffering from a chronic laryngeal condition for some time. Once there, he spent time as a volunteer working in the South African Museum under Edgar Layard,1 its first Curator, cataloguing and arranging the collection of Lepidoptera. Needing an income, he joined the Cape public service in 1860 as a third-class clerk. He progressed to private secretary to the Colonial Secretary Richard Southey (1808- 1901), and then became personal secretary to the Governor, Sir Henry Barkly (1815-98).2 This enabled Trimen to escort Barkly, a keen amateur botanist, on his visits around the colony. Between them they investigated the insects and plants of each area they visited. Barkly himself discovered many species of succulents new to science.

In his spare time Trimen worked on a catalogue of South African butterflies, rather grandly called Rhopalocera Africae australis.: a catalogue of South African butterflies, comprising descriptions of all the known species, with notices of their

205



206 Alan Cohen

Figure 1. Roland Trimen. (Photograph reproduced courtesy of the Royal Entomological Society, London.)

larvae, pupae, localities, habits, seasons of appearance, and geographical distribution. It appeared in print in two parts in 1862-66 and, as the first book solely devoted to the region's butterflies, was an amazingly comprehensive work for such a young man. Linnaeus had grouped the order Lepidoptera into three genera: Papilio (the butterflies), Sphinx (the hawkmoths) and Phalaena (all the other moths). Trimen preferred to follow a system of division based on the antenna shape, in which there were only two main groups, the Rhopalocera or butterflies (the word means 'club horned' and was introduced by Dum6ril in 1823), and the Heterocera ('different horned') for all the moths.

In November 1861 Layard introduced Trimen to James Henry Bowker, who had sent a collection of butterfly specimens to the museum the previous year. The



Roland Trimen and the merope harem 207

collection, mainly from the Transkei region, where he was stationed as Commandant of the Frontier Armed and Mounted Police at Fort Butterworth, was an important acquisition for the South African Museum and was noteworthy enough to have been reported in the Cape Argus in May 1860. Soon after he had arrived in Cape Town, Trimen met one of Henry's older brothers, Thomas Holden Bowker, who had fascinated him with 'stories of adventure among wild animals and in Kafir [sic] wars'.3 The Bowkers were a large and well-known family, who had arrived at the Cape in 1820 as part of the British Settler movement.

As soon as the first part of Trimen's Rhopalocera was printed, Henry Bowker suggested that his sister Mary might be interested in helping with illustrations for the next volume. He wrote to Trimen on 14 July 1862 from Fort Bowker, where he was then stationed, some 30 miles northeast of Butterworth:

Thanks for the book which came to hand safe what a pity it cannot be illustrated I am trying to get my sister Mrs Barber to illustrate a copy as she can do it well and the book would be valuable I think I told you that she painted the whole of the Albany butterflies and Moths it was a work of many years, but was valuable as it were well done and mostly done upon the flowers which they loved to frequent....4

Mary Barber had been a two-year-old child when her parents arrived in South Africa, also as part of the British Settler movement. Although she had no formal education, and was married to a sheep farmer near Grahamstown in the Eastern Province of Cape Colony, she had begun to make a name for herself as an amateur natural historian, with particular interests in botany and ornithology. Her contact with Trimen continued for over 30 years until her death in 1899, and several other members of her family were included. Henry and Mary continued to be among Trimen's chief sources of local specimens and information, and in a letter to Darwin Trimen once referred to Henry as 'My best correspondent, a gentleman in the Frontier Mounted Police...'.

Eventually Henry co-authored Trimen's major work on South African butterflies, published in 1887.5

Profoundly influenced by The origin of species, Trimen had once seen Charles Darwin in the Insect Room of the British Museum, but had not dared speak to him. Darwin's publication On the various contrivances by which British and foreign orchids are fertilised by insects appeared in 1862, and was close to his own researches. Trimen eventually summoned up the courage to write to Darwin around the end of the year. He expressed his interest in the pollination of plants by insects, and in particular in the association of butterflies with orchids.6 Darwin replied that he was astonished by the different forms of orchids that Trimen described, and urged him to experiment with only two or three of the more distinct genera as

I believe, or am inclined to believe in one or very few primordial forms, from community of structure and early embryonic resemblances in each great class.7

Darwin was soon instrumental in the publication of Trimen's first academic paper. During the same month in which Trimen started his lengthy correspondence with Mrs Mary Elizabeth Barber, Darwin wrote8 that he had drawn up a paper that



208 Alan Cohen

he had communicated to the Linnean Society based on Trimen's notes on the fertilization of the orchid Disa grandiflora. It was published by the Society later that year.9 In Mary's first letter to Trimen, she explained that the peach crop in her orchard had just been devastated by a plague of moths that penetrated the fruit skins to extract the juices, and asked for his help in identifying the moth. Trimen knew that Darwin believed, although so far he had no evidence, that nocturnal-flying moths were largely responsible for effecting the pollination of certain orchids at the same time as they punctured the plants' nectaries to obtain the nectar inside. Most entomologists at the time, including Trimen, thought that moths were incapable of penetrating such strong membranes. Mary Barber had just supplied the corroborative evidence, and the now thoroughly convinced Trimen immediately wrote to Darwin to inform him of the discovery. 10

MIMICRY AND NATURAL SELECTION

After some years studying the taxonomy of South African butterflies, Trimen became interested in the new discoveries of mimicry among butterflies that were then being revealed in other parts of the world. From 1848 to 1859 a young amateur naturalist, Henry Walter Bates" (1825-92, F.R.S. 1881), had explored the Amazon Basin, at first in company with his friend Alfred Russel Wallace (1823-1913, F.R.S. 1893).12 Bates's discoveries led him to speculate on the influence of natural selection in the evolution of species.13 In this he followed his friend Wallace, who had formulated the hypothesis of natural selection independently of Darwin during a further excursion to the Malay Archipelago.14 The publication of Darwin's The origin of species, a few months after Bates's return to England, led to a realization by Bates that he had produced the best evidence so far of the correctness of this new theory. In 1861 he wrote to Darwin to say that his researches and discoveries in the Amazon had led him to believe that he had seen 'a glimpse into the laboratory where Nature manufactures her new species'. Bates had also been intrigued by the large numbers of butterflies in the Amazon that resembled other species, especially those he called the Heliconidae (now considered to be a subfamily of the Nymphalidae and more correctly called Heliconiinae).15 Darwin encouraged him to publish his information. This he did as part of a paper on the Amazonian butterflies read to the Linnean Society of London on 21 November 1861, and later published in the Society's Transactions.16 Bates was thus one of the first to incorporate Darwin's ideas into his own publications. He described in great detail the similarities in markings between several unrelated species. He explained why he considered the Heliconidae, generally thought to be inedible by predatory birds, to be the models, and the others, such as the similarly coloured Dismorphia butterflies,1 which were apparently edible, to be the mimics. He came to the conclusion that the more palatable species had, over time, evolved similar markings to the inedible Heliconidae; in other words they mimicked them, and by this method avoided being eaten. This process soon became known as Batesian mimicry, and is still generally considered to be well illustrated




among butterflies. However, since the publication of the work of Fritz Mfiller18 in 1879 it is now known to be much more complex.

At the time most people, including Bates, thought that variability within a species was an outcome of environmental influences. Mendel's work on the genetic causes for such variability was then unknown.19 After Bates's lecture to the Linnean Society, his discussions with Joseph Hooker, the Director of Kew Gardens, convinced him that Darwin's theory showed how natural selection acted on the variations to ensure the survival of the fittest, and his written publication was altered to reflect this change in attitude. In his summing up he stated:

I believe the case offers a most beautiful proof of the truth of the theory of natural selection. It also shows that a new adaptation, or the formation of a new species, is not effected by great and sudden change, but by numerous small steps of natural variation and selection.20

The advocates of natural selection considered mimicry to be one of the first important proofs of Darwin's explanation of how some species evolved rather than others, and Bates provided an early exemplar showing that it was applicable to the natural world as well as the domesticated species that Darwin had mostly used to establish the theory.

Bates's paper was followed in March 1864 by one from Wallace, who had meanwhile been studying the butterflies in the Malay archipelago.21 In his presentation to the Linnean Society, Wallace discussed 120 species of Papilionidae that he had investigated. He attempted to classify variability among them and to establish some of the reasons for the different types he had encountered. He noted that it was only the females who were mimetic and introduced the concept of mimetic polymorphism, in which not only were the males and females markedly different in appearance, but the females themselves exhibited different forms. As an example he chose the Malayan P memnon, stating that the bluish-black male never varied, but there were two female forms, both unlike the male. Each generation produced similar results: males all alike and two kinds of female. It is now understood that this pattern of polymorphism is not true of all papilionid species and in some, such as Chilasa, both sexes are mimetic and polymorphic. He then went on to discuss the resemblances between the Malayan and Indian Papilionidae and the Danaidae. The latter were exceptionally prolific, and he believed their strong odour to be the reason for their ubiquity, because most insect predators avoided them. The advantage gained by other insects in mimicking the Danaidae markings was obvious. He explained:

... let a Papilio resemble a Danais so slightly that it is only mistaken for it by very unobservant birds, &c., or at a considerable distance. Even this will be some advantage to it, for many individuals that would otherwise have been devoured will now live and leave offspring. But every animal varies more or less, sooner or later. Among the varieties of this Papilio some must be more like, some less like the Danais. The former will escape persecution more than the latter-will increase, therefore, while the latter will diminish. In each succeeding generation this preservation of the more like and the destruction of the less like will go on, which must slowly, but surely, produce a gradually increasing likeness, till the one insect can hardly be distinguished from the other. Such cases occur everywhere.



210 Alan Cohen

Some of the more remarkable have been pointed out by Mr. Bates as occurring in South America, where every streak and spot, as well as the exact outline, has been copied by insects of a quite different structure. ... No less than fourteen Indian and Malayan Papilios mimic species of distinct groups, in several cases so closely that they have been placed by entomologists in the same species, although really having no close affinity; and the writer was constantly deceived by them on the wing. We cannot wonder, therefore, that birds and insects also confound them.22

THE 'CENEA' CONTROVERSY

The study of the taxonomy of Lepidoptera has progressed, and what were in Trimen's time thought to be several distinct species of Papilio (namely cenea, merope, dionysos, hippocoon and trophonius) are in fact only a few of over 30 different forms of the African 'mocker swallowtail' now known as

P. dardanus Brown (figure 2).23 It

is considered to be one of the most spectacular examples of Batesian mimicry.24 Trimen had captured his first P cenea in 1858, soon after he arrived in the Cape, and was puzzled by its relationship to P merope. Male merope were plentiful, and although this female cenea resembled them there were enough differences to make him think '...she was an illegitimate hybrid between the noble Merope and the dusky Danais (Amauris) Echeria!'-a similar species.25 However, it was not until 1866 that he began to think seriously about the problem of the missing merope females when, soon after reading Bates's article on the Amazonian Heliconidae, he received a request from Mrs Barber for a specimen of a male cenea so that she could include it in her series of drawings of South African butterflies and their food plants. He was astonished that on searching through the available collections 'no such creature as a male cenea could be found'. He had obviously forgotten that Mrs Barber had already raised the problem two years earlier when she wrote to him:

... of P Cenea the Y here is like your description of the 6 in every respect we have taken several of them and they are all alike and I am quite sure they are females, we have not taken the 6 here this season at all, as yet.26

By 1866, although she had asked for one she was beginning to be doubtful that male cenea existed:

... the brick red Y Cenea described in your book is not with us, I do not know him, are you sure that it is Mistress and Master that you describe there?27 Trimen had now realized that there were several anomalous butterflies in the

region that he could not explain and began to think that those he had previously thought to be separate species, namely P cenea, P dionysos, P hippocoon and P trophonius, might in fact be four forms of the female of one species. There is no evidence that he knew of Wallace's 1864 paper (which was not published by the Linnean Society until 1865) in which Wallace mentioned that eggs laid by the Indian butterfly P polytes produced adults of both itself and P pammon, then thought to be a different species but thus proved to be a different form of the parent.28 In his paper read to the Entomological Society (known as the Royal Entomological Society from




l.LATE I. Frontispiece. ? PA 11EN .

pp ocoon. )ANAIN .1MOI)ELS. OFFSPRING.

,Ionfinicans 2T

Danaida (Limnas) 2 form irophonius. chrysippus c'.

.4 mauris a/bimacublta 2 2 for;n cenea.

Mrs. P.

. \\hulpicy. p sx A drc

& ,.h . Lti.

Allfiiiirs iC.,

iorit itf i.the inatirl ,,size.

Jxaitqlilcs of the mirmetic female forms of 'Apilio idaraaus.

subsp. ,e'ea,

bred in 19(6 fr1 a i/.poI o form of female: Durban, Natal. The female parent and the l1anaine models from the same locality are also figured.

Figure 2. Plate 1 frontispiece from The Journal of the East Africa and Uganda Natural History Society, vol. 20 (1924). Mimetic female forms of Papilio dardanus subsp. cenea. (C 2002 The Natural History Museum, London.)



212 Alan Cohen

1885) in 1873, Trimen relates that on receipt of Mrs Barber's letter he immediately wrote back to tell her of his theory, and that although 'somewhat incredulous' she was not 'unprepared to find it turn out to be a true one'. In fact she replied:

Your letter of July 2nd has arrived 'all right' and I must say that I was somewhat astonished at its contents, and I scarcely know what to think of it, or how much of it to believe! but the idea is well worth investigating, I recollect saying to the boys last season 'how is it that all these Meropes seem to be 6 s' ... I am glad you have told me of this notion it would be very interesting if it were to turn out to be true, and after the discoveries that Mr Darwin made amongst the Orchid tribe, even this will not be incredible but only another parallel.

I should long ago have made a drawing of P. Cenea together with their food plant but I have always been puzzled about the 6, like yourself I have once or twice fancied that small ones were males.29

Several of Mrs Barber's letters to Trimen during 1866 mention the problem. In October she wrote:

Try if you can find any 9 s amongst the Meropes and of course if you can find any, the mystery as far as a Merope is concerned, is at an end, I have examined a good many dried ones, in collections, and they are evidently all CTs....30 In 1867 Trimen himself sought P merope and cenea in Natal but failed. Later in

the year he returned to England and following further research in British collections he became convinced that he was correct regarding his theory of the sexual orientation of these butterflies.31 In December he informed the Entomological Society of his ideas and said that he would enlarge on his findings at a later date.

On 5 March 1868 he presented his conclusions to the Linnean Society.32 He commenced his paper by pointing out that although Jean Alphonse Boisduval (1801-79) had, 30 years before, noted the strange resemblances between some distantly related butterflies, no entomologist before Bates had sought an explanation but had 'let them pass as things inscrutable'. Trimen believed, like Darwin and Bates, that explanations should be sought and that the answers would be found within the theory of natural selection. He noted that P cenea imitated Danais echeria; P hippocoon and P dionysos imitated D. niavius;33 and P trophonius copied D. chrysippus and that these four Papilionidae, previously thought to be separate species, were in his opinion all female forms of P merope. In spite of Wallace's earlier report that different female forms of the Indian butterfly P pammon had been reared from a single batch of eggs, Trimen's ideas were not well received by some entomologists, especially WC. Hewitson (1806-78), who had the finest collection of butterflies in England at the time, and J.O. Westwood (1805-93), the Hope Professor of Zoology at Oxford. Although Hewitson agreed that hippocoon and dionysos were now to be considered as one species, he could not accept that they were both females of merope. He pointed out that in Madagascar there were females that exactly resembled the male merope and was scathing in his remarks:

.. it would require a stretch of the imagination, of which I am incapable, to believe that the P Merope of the mainland, having no specific difference, indulges in a whole harem of females, differing as widely from it as any other species in the genus.34 He went on to imply that although some strange anomalies in the sexes were

becoming known, such a degree of difference shocked his 'notions of propriety'.




Although Trimen's ideas were welcomed by Bates when he addressed the Entomological Society on 25 January 1869, further proof was obviously needed. Trimen realized that it could only be achieved by collecting P cenea eggs and raising the adult butterflies from them. Indeed, Mrs Barber had already written to him in June 1868, implying that he needed to do this:

Ceneas food plant is the White Ironwood tree, I have seen her laying her eggs high up amongst the lofty branches of that tree, altogether beyond reach or I would have collected and tried to have reared them...35

In his reply he specifically asked her to try to rear cenea and merope from cenea eggs. This was to prove more difficult than he at first hoped. Mrs Barber replied to his request:

Your plan regarding Mrs Merope is a good one, and if I can only get hold of her I will try it this next season that is coming, the worst of it is they are very rare here, some seasons pass away without our taking any of them....36

Unfortunately by 29 February 1869 she had to write:

Alas! And welladay! I have not seen a single live specimen of either Merope or Cenea this season, what is to be done? If things go on at this rate the mystery will never be cleared up. I am disgusted.37

It was still no better a year later, and on 20 February 1870 she wrote, 'Cenea is exceedingly rare, it is two years since I saw one, if ever I have a chance I will do as you mentioned'.

In fact Mrs Barber herself never succeeded in rearing merope or cenea from eggs and it was another of Trimen's amateur entomological correspondents, J.P.M. Weale,38 who eventually announced in a letter dated 3 March 1873 that he had 'six larvae of Cenea-Merope, all in good health-one just out of egg'. On 14 April he reported that two specimens of merope, a hippocoon and a cenea, had emerged from the first four pupae. Accompanying the letter were two pupae, one of which had died, but from the other Trimen was delighted to see emerge a perfect merope. A later brood produced a trophonius as well.39

In his letter Weale commented on how closely the pupae resembled the living plant to which they were attached, to the extent that the ventral and dorsal aspects of the chrysalis were different shades of green, corresponding to the upper and lower surfaces of the leaves. Trimen found it surprising that the mimicry evidenced by the imagos should seem to be so marked in the pupae as well. It seems he was probably unaware of Mrs Barber's experiments with rearing P nireus from their eggs. She had asked her brother to tell him during a visit to Cape Town but presumably he forgot, and she had sent her results to Joseph Hooker at Kew in August 1874. He immediately passed them on to Darwin, who communicated her findings to the Entomological Society in November.40 She reported that although the imago preferred the flowers of the Cape leadwort (Plumbago capensis),41 the caterpillars assumed the green colours of the leaves of the orange tree and an indigenous forest tree, the white ironwood (Vepris lanceolata), upon which they normally fed. However, when reared in a case made of wood and a brick frame with a glass cover,



214 Alan Cohen

the pupae assumed the colour of whatever part they attached themselves to. One even became part wood and part brick-coloured.

Both Weale and Mrs Barber had commented on how closely the male merope managed to blend into its surroundings because of the colours of the closed wings of the adult. Thus the insect was doubly protected by imitating both its surroundings and models that were unpleasant to predators. Today, protection by colour is more correctly termed 'camouflage' when a creature blends in with its surroundings, and 'disguise' when it attempts to imitate a specific aspect of the environment. However, it is important to note that the underlying mechanisms are quite different. Environmental switching in the pupa is controlled chemically, whereas mimicry in the adult is predetermined by simple genetic factors. Mrs Barber again gave Trimen excellent examples of both types when she described how

Master Merope thought proper to seek a resting place, which he wisely chose upon a shrub which resembled his own coulors [sic] on the under side, it was a splendid match, when he closed his wings amongst the yellow and brown seeds and flowers of the shrub, no bird would have ever distinguished him, ... I believe all Butterflies do this, where it is possible to match their colours; Cardui will always take a mottled stone or old wall, however I often see Chrusippis [sic] perched at the extremity of a tall rush, or grass stem, whose hue was no colour resembling her own, but in this case she was passing herself off as a flower, and I do assure you she looked like one.42

Weale had produced the proof that Trimen had sought for so long. He showed that all these four butterflies, P cenea, P hippocoon, P dionysos and P trophonius, hitherto thought separate species, were in fact one and the same. Now Trimen could confirm that all were female forms of the one species, of which the male was P merope. In his report to the Entomological Society he could not resist commenting:

It is with reluctance that one contemplates the stretching of Mr Hewitson's imagination to the extent 'of which he is incapable,' or the inevitable shock which his 'notions of propriety' will receive, but the evidence now adduced by Mr Weale is such that the profoundest sceptic cannot explain it away, and must allow that the dream had proved to be a true vision.43

However, the final link in the chain was not completed until 1881. On 22 February, James Henry Bowker observed and captured P merope and P cenea in the act of mating, thus confirming the life cycle of these fascinating creatures.44

There was one major inconsistency in mimicry that neither Bates, Wallace nor Trimen could explain. All three had noted the close resemblances between unrelated butterfly species that were all distasteful to predators and should therefore have not needed to mimic others. It was not until 1879 that Fritz Milller offered an explanation. In his paper on the Danainae Ituna and Thyridia45 he suggested that it was a question of percentages. The more individuals there were that looked alike to young inexperienced predatory birds, the more chance there was of the birds' experiencing a distasteful meal and learning to ignore similar specimens in the future. In probably the earliest use of mathematics to explore evolutionary processes, Miuller showed that the ratio of advantages for mimicry was greatly in favour of the rarer species--in proportion to the square of the ratio of relative abundances. The




greater the disproportion in numbers between the more common and the rarer species, the more the rarer one stood to benefit. However, both species suffered to enable the maximum number of individuals to escape. This type of mimicry, in which all the mimics are unpalatable, is now known as Miillerian mimicry, in contradistinction to Batesian mimicry in which the mimics are all palatable. However, it should be mentioned that there is now a body of opinion that considers it difficult to categorize mimicry definitely in this way. Bernardi46 and Vane-Wright47 in particular claim that the classic theory of Batesian mimicry is not adequately proved and that much butterfly mimicry might in fact be Miillerian in type.

Although Trimen himself claimed no originality for his work on mimicry, its major importance was that by 1873 there was acknowledged to be a solid body of evidence from at least three continents-the Americas, Asia and Africa-attesting to the truth of Darwin's natural selection theory of the evolution of species. Although 14 years had passed since The origin of species had been published, there were still many doubters, but at last there was sufficient confirmatory evidence, chiefly from the fieldwork of Bates, Wallace and Trimen, in favour of Darwin's theory to encourage acceptance now among the more forward-thinking scientists of the day.

Although Bates and Wallace were more concerned with the taxonomic and zoogeographical issues arising from mimicry, Trimen was almost certainly the first to regard it as a topic worthy of study in itself.48 His original work has led to considerable further study of P dardanus and its forms. In 1924 Sir Edward Poulton (1856-1943, ER.S. 1889) called it 'the most interesting butterfly in the world'.49 During the 1960s and 1970s Sir Cyril Clarke (1907-2000, ER.S. 1970), with the geneticist Philip Sheppard (1921-1976, ER.S. 1965), undertook a detailed study of mimicry. Their research into the inheritance of butterfly colours with the use of P dardanus and P memnon as prime examples produced a most unlikely result. Clarke was by profession a consultant physician, and their studies led them to look at human rhesus blood groups that have similar patterns of genetic interaction.50 This led in turn to the development of a method of preventing rhesus haemolytic disease that has probably saved hundreds of thousands of lives worldwide over the past 30 years.51

ACKNOWLEDGEMENTS

My thanks are due to the Royal Entomological Society for permission to access their Roland Trimen correspondence and to use the illustrations, to Charles Smith of Western Kentucky University for his help with material about Wallace, to James E. O'Hara of the Centre for Land and Biological Resources Research in Ottawa for a copy of his paper on Bates, and to Kate Pritchard (Archivist at the Royal Botanic Gardens Kew), Gina Douglas (Librarian of the Linnean Society of London) and Berit Pederson (Librarian of the Royal Entomological Society) for their help in unearthing obscure material from their archives. I am also grateful to Bryan Stokes, Archivist of the Old King's Club, for information about Roland Trimen's schooldays.



216 Alan Cohen

NOTES

1 Edgar Leopold Layard (1824-1900) was the younger brother of Sir Henry Austin Layard, the excavator of Nineveh. He started his career in the Ceylon Civil Service. A keen conchologist and ornithologist, he was invited to the Cape by the then Governor, Sir George Grey, as his private secretary and became the first curator of the South African Museum in 1855. He received a C.M.G. for his services in the cession of Fiji to Britain and was its first administrator. His book The birds of South Africa (Cape Town, 1867) relied greatly on information supplied by amateurs such as Mrs M.E. Barber.

2 Sir Henry Barkly (1815-98), British Governor of Guiana 1848-53, Jamaica 1853-56, Victoria, Australia 1856-63, and the Cape of Good Hope from December 1870 to March 1877. He annexed for Britain the diamond fields in 1871 and the Transvaal in 1877.

3 From a letter to Mary Layard Bowker dated 7 November 1885, Gareth Barberton Archive. 4 Trimen Correspondence Box 19/195.1. 5 R. Trimen and J.H. Bowker, South-African butterflies: a monograph of the extra-territorial

species (Triibner & Co., London, 1887). 6 The Trimen/Darwin letters were published as early as 1909 by E.B. Poulton in Charles

Darwin and the origin of species, pp. 213-246 (Longmans, London). 7 A calendar of the correspondence of Charles Darwin 1821-1882 (Cambridge University

Press, 1994), letter number 3956, dated 31 January 1863. 8 Ibid., number 4179, dated 23 May 1863. 9 C. Darwin, 'On the fertilisation of Disa grandifloria, Linn.' J Linn. Soc. Lond. (Bot.) 7,

144-147 (1863). 10 Darwin Correspondence DAR 99:13-16d, Cambridge University Library. 11 Bates was President of the Entomological Society in 1869 and 1878, and assistant secretary

to the Royal Geographical Society from 1864 to 1892. 12 Wallace's researches in the Amazon Basin had led him to think about the transmutation of

species for at least three years before he wrote to Darwin in 1858. His first paper on the subject, 'On the law that has regulated the introduction of new species', was published in Annals and Magazine of Natural History for September 1855.

13 For details of Bates's life and achievements see James E. O'Hara's excellent account 'Henry Walter Bates--his life and contributions to biology', Arch. Nat. Hist. 22, 195-219 (1995).

14 The so-called Ternate essay, 'On the tendency of varieties to depart indefinitely from the original type', written by Wallace and sent to Darwin in February 1858, set out his ideas on the survival of the fittest, and led to the special meeting of the Linnean Society of London on 1 July 1858 at which both Wallace's and Darwin's papers were presented by Sir Charles Lyell and Joseph Dalton Hooker under the joint title 'On the tendency of species to form varieties; and on the perpetuation of varieties and species by natural means of selection'.

15 The butterflies that Bates knew as Heliconidae now include two groups of Nymphalidae as currently classified, some in the subfamily Heliconiinae and some in the Danainae. The classification of the Lepidoptera has changed considerably over the years, and is still fluid. For the latest views see part 3 of M. J. Scoble, The Lepidoptera: form, function and diversity (Oxford University Press, 1995), J. B. Heppner, Classification of Lepidoptera, vol. 1 (Introduction, Holarctic Lepidoptera, Suppl. 1) (1998) or Handbook of zoology (ed. N.P. Kristensen), vol. 4 (35) (Lepidoptera, moths and butterflies) (de Gruyter, Berlin, 1999).

16 H.W Bates, 'Contributions to an insect fauna of the Amazon valley, Lepidoptera: Heliconidae', Trans. Linn. Soc. Lond. 23, 495-515 (1862).

17 Family Pieridae. 18 Dr Johannes Friedrich Theodor 'Fritz' Miuller (1822-97) was an enthusiastic proponent of

Darwin. He was the first to realize the complexity of the social system of termites, and worked extensively on mimicry in butterflies.




19 Mendel's findings on plant hybridization were presented in two lectures before the Society for the Study of the Natural Sciences in Brfinn in 1865. His paper, 'Versuche fiber Pflanzen- Hybriden' ('Experiments in plant hybridization'), was published in the Society's Proceedings in 1866 and sent to 133 other associations of natural scientists and to the more important libraries in several different countries. Mendel also sent reprints to scholars outside Brfinn. However, his work was largely ignored. In the spring of 1900, three botanists, Hugo de Vries in Holland, Karl Correns in Germany and E. von Tschermak in Austria, reported independent verifications of Mendel's work that amounted to a rediscovery of his first principle.

20 Bates (1862), op. cit., p. 513. 21 'On the phenomena of variation and geographical distribution as illustrated by the

Papilionidae of the Malayan region' (a paper read at the Linnean Society of London meeting of 17 March 1864), Trans. Linnean Soc. Lond. 25 (I), 1-71 (1865).

22 'Mr. Wallace on the phenomena of variation and geographical distribution as illustrated by the Malayan Papilionidae', Reader 3, 491b-493b (no. 68, 16 April 1864). This is an abstract of his classic paper read to the Linnean Society.

23 The butterfly known to Trimen as P merope was described by Cramer in 1777. It was later realized that it had been described a year earlier by Brown and given the name dardanus; it is this name that now stands.

24 M. Salvato, University of Florida book of insect records, chapter 28 (1997) (http://recbk.ifas.ufl.edu/).

25 R. Trimen, 'Observations on the case of Papilio Merope, Auct. with an account of the various known forms of that butterfly', Trans. Entomol. Soc., part 1 (Feb.), 137-153 (1874).

26 Trimen Correspondence Box 17/35, dated from Highlands 10 February 1864. 27 Trimen Correspondence Box 17/46, dated from Highlands 15 June 1866. 28 See note 21. 29 Trimen Correspondence Box 17/48.1, dated from Highlands July 1866. 30 Trimen Correspondence Box 17/53.1, dated from Highlands 1 October 1866. 31 Trimen's searches in British collections are detailed in E.B. Poulton's article 'Papilio

dardanus. The most interesting butterfly in the world', in J East Afr. Nat. Hist. Soc. 20, 4-22 (1924).

32 R. Trimen, 'On mimetic analogies among African butterflies', Trans. Linn. Soc. Lond. 26, 497-522 (1869).

33 The butterflies known to Trimen as D. echeria and D. niavius are now classified as Amauris echeria and A. niavius, and the spelling of Danais has been changed to Danaus.

34 W.C. Hewitson, in Illustrations of new species of exotic butterflies, selected chiefly from the collections of

W. W. Saunders and

W.C. Hewitson (London, 1851-76), pt 72 (Oct. 1869).

35 Trimen Correspondence, Box 17/60.1 dated from Highlands 21 June 1868. 36 Trimen Correspondence, Box 17/61 dated from Highlands 1 August 1868. 37 Trimen Correspondence, Boxes 17/64 and 65 dated from Highlands 29 February 1869. 38 James Philip Mansel Weale (1838 to after 1911) was an old school friend of the Trimen

brothers. He studied law at Oxford, then took up farming in South Africa from the mid- 1860s until about 1890, when he returned to England. His especial interest was the pollination of flowers by insects. He corresponded with Darwin, who communicated several papers for him to the Linnean Society.

39 J.P. Mansel Weale, 'Notes on the habits of Papilio merope, with a description of its larva and pupa', Trans. Entomol. Soc., part 1, 131-136 (1874).

40 M.E. Barber, 'Notes on the peculiar habits and changes which take place in the larva and pupa of Papilio Nireus', Trans. Entomol. Soc., part 4 (Dec.), 519-521 (1874).

41 Plumbago capensis is now correctly called Plumbago zeylanica L.; Mrs Barber did not give a Latin name for the 'Orange tree'.

42 Trimen Correspondence, Box 18/82 dated from Highlands 30 January 1871.



218 Alan Cohen

43 R. Trimen, 'Observations on the case of Papilio merope, Auct.; with an account of the various known forms of that butterfly', Trans. Entomol. Soc., part 1, 141 (1874).

44 R. Trimen, 'Note on the capture of the paired sexes of Papilio Cenea, Stoll. (P Merope, auct.), in Natal', Trans. Entomol. Soc., part 2 (July), 169-170 (1881).

45 The paper was first published as 'Ituna and Thyridia; a remarkable case of mimicry in butterflies', Kosmos, p. 100 (May 1879); it was translated by Professor Meldola, communicated to the Entomological Society in May 1879 and published in Trans. Entomol. Soc., 20-29 (1879).

46 G. Bernardi et al., 'Le polymorphisme et le mim6tisme de Papilio dardanus Brown (Lep. Papilionidae)', Soc. Ent. Fr. Bull. 90, 1116-1158 (1985).

47 R.I. Vane-Wright and C.R. Smith, 'Phylogenetic relationships of three African swallowtail butterflies, Papilio dardanus, P phorcas and P constantinus: a cladistic analysis (Lepidoptera: Papilionidae)', Syst. Entomol. 16, 275-291 (1991).

48 Muriel L. Blaisdell, Darwinism and its data. the adaptive coloration of animals (Garland Publications, New York, 1992), pp. 169-181.

49 E.B. Poulton, 'Papilio dardanus. The most interesting butterfly in the world', J.

East Afr. Uganda Nat. Hist. Soc. 20, 4-22 (1924).

50 Summed up in C.A. Clarke, EM.M. Clarke and I.J. Gordon, 'Mimicry and other controversial topics in East African Lepidoptera', J. East Afr. Nat. Hist. Soc. 84, 3-18 (1995).

51 C.A. Clarke, 'Preventing Rhesus babies: the Liverpool research and follow-up', Arch. Dis. Childh. 64, 1734-1740 (1989).



roland trimen and the 'merope' harem

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