MIMICRY, MUTATION AND MENDELISM 



I propose to consider two important examples of mimicry in 

 African butterflies — examples on which much new light has been 

 shed by recent researches. The models for mimicry belong, with 

 a single exception, to the Danaince : the exception is an Acrseine. 

 The Danaince and Acrceince have been shown by many experiments 

 to be distasteful to insect-eating animals, and both are extensively 

 mimicked in other parts of the world as well as in Africa. 



First, Papilio dardanus, or, as it used to be called, Papilio merope. 

 The train of mimetic females accompanying the non-mimetic male 

 of this species and changing in relation to the models in various 

 parts of Africa has often been spoken of as the most wonderful 

 example of mimicry in the world. The splendid conclusions 

 announced by Roland Trimen in 1868 are clearly shown in the 

 accompanying Plate I. When Trimen began his enquiries the 

 butterfly shown in Fig. 1 was known as Papilio merope, that in 

 Figs. 6 and 7 as P. hippocoon, in Fig. 8 as P. trophonius, in Figs. 9 

 and 10 as P. cenea. All these were considered to be entirely distinct 

 species. After studying all the material available in museums and 

 private collections in Africa and Europe, Trimen found that merope 

 was invariably a male and the other three invariably females. By 

 a masterly analysis of the markings of the three female forms and 

 their varieties he brought out the essential resemblance that underlay 

 the superficial divergence ; while, by comparison with the non- 

 mimetic female of an allied species in Madagascar (Plate II., 

 Figs. 1 and 2), he was able to suggest the origin of the female forms 

 from a pattern closely similar to that of the male. 



All this evidence was discussed in Trimen 's great memoir in the 

 Transactions of the Linnean Society for 1869 (Part III. of Vol. XXVI., 

 p. 497), in which he established the conclusion that hippocoon 

 (Fig. 7 on the accompanying Plate I.) is a female form of merope 

 (Fig. 1) modified by mimicry of the conspicious Danaine Amauris 

 dominicanus (Fig. 2), that another female form, trophonius (Fig. 8), 

 arose in mimicry of Danaida chrysippus (Fig. 3), and a third, cenea 

 (Figs. 9 and 10), in mimicry of Amauris echeria (Fig. 5). These 

 views at first met with opposition and even ridicule, but confirmation 

 of various kinds rapidly accumulated, and Trimen's conclusions 

 were generally accepted long before the final proof was obtained at 

 Durban in 1902, when G. F. Leigh bred eighteen males {merope), 



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