Admires ARW's "Theory of birds' nests" [J. Travel & Nat. Hist. 1 (1868): 73].
Discusses their respective views on birds' nests, sexual selection, and protection.
Asks why, if brilliant colours of female butterflies are result of protective mimicry, do not males become equally brilliant? CD believes variation in females alone accounts for it, rather than protection.
Down. | Bromley. | Kent. S.E.
My dear Wallace
I have been deeply interested by your admirable article on Birds' nests.— I am delighted to see that we really differ very little,—not more than two men almost always will—
You do not lay much or any stress on new characters spontaneously appearing in one sex (generally the male) & being transmitted exclusively, or more commonly only in excess, to that sex.— I on the other hand formerly paid far too little attention to protection. I had only a glimpse of the truth. But even now I do not go quite as far as you.— I cannot avoid thinking rather more than you do about the exceptions in nesting to the rule, especially the partial exceptions, i.e when there is some little difference between the sexes in species which build concealed nests.
I am not quite satisfied about the incubating males: there is so little difference in conspicuousness between the sexes.— I wish with all my heart I could could go the whole length with you.— You seem to think that male birds probably select the most beautiful females; I must feel some doubt on this head, for I can find no evidence of it. Though I am writing so carping a note, I admire the article thoroughily.—
And now I want to ask a question.— When female Butterflies
are more brilliant than their males you believe that they have
in most cases or in all cases been rendered brilliant so as to
mimic some other species & thus escape danger. But can you
account for the males not having been rendered equally
brilliant & equally protected. Although it may be most for
the welfare of the species that the female should be
protected, yet it would be some advantage, certainly no
disadvantage, for the unfortunate male to enjoy an equal
immunity from danger. For my part, I should say that the female
alone had happened to vary in the right manner, & that the
beneficial variations had been transmitted to the same sex
alone.— Believing in this, I can see no improbability (but
from analogy of domestic animals a strong probability) that
variations leading to beauty must often have occurred in the
males alone, & been transmitted to that sex alone. Thus I sh
I hope that your Eastern Book progresses well—
My dear Wallace | Yours sincerely | C. Darwin
- f1 6121.f1The year is established by the reference to A. R. Wallace 1868 (see n. 2, below).
- f2 6121.f2CD refers to Wallace's paper `A theory of birds' nests', which appeared in the April 1868 issue of Journal of Travel and Natural History (A. R. Wallace 1868).
- f3 6121.f3Wallace had argued that birds with both sexes brightly coloured built concealed nests while those with only one of the sexes brightly coloured built open nests (A. R. Wallace 1868, p. 78).
- f4 6121.f4Wallace had given examples of birds in which the female was more brightly coloured than the male and noted that in these rare cases the male incubated the eggs (A. R. Wallace 1868, pp. 83--4).
- f5 6121.f5CD probably refers to a passage where Wallace states that `the normal action of `sexual selection' is to develop colour and beauty in both sexes, by the preservation and multiplication of all varieties of colour in either sex which are pleasing to the other' (A. R. Wallace 1868, p. 82).
- f6 6121.f6See, for example, A. R. Wallace 1866 and [A. R. Wallace] 1867b, pp. 24--5.
- f7 6121.f7CD refers to The Malay Archipelago (A. R. Wallace 1869). CD had encouraged Wallace to write the book (see letter from A. R. Wallace, 7 February 1868, n. 4, and letter to A. R. Wallace, 22 February ).