Talk:Trimorphism

Latest comment: 5 years ago by Humanengr in topic This line seems a misreading of Wallace

This line seems a misreading of Wallace

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"Wallace has shown that the females of certain butterflies from the Malay Archipelago appear in three conspicuously distinct forms without intermediate links."

No cite is provided, but I found on p. 200 of Wallace's Malay Archipelago (also here) a picture of the two female forms of Papilio Memnon, and related text from p. 202:

But the most curious fact connected with these distinct forms is, that they are both the offspring of either form. A single brood of larvæ were bred in Java by a Dutch entomologist, and produced males as well as tailed and tailless females, and there is every reason to believe that this is always the case, and that forms intermediate in character never occur. To illustrate these phenomena, let us suppose a roaming Englishman in some remote island to have two wives—one a black-haired red-skinned Indian, the other a woolly-headed sooty-skinned negress; and that instead of the children being mulattoes of brown or dusky tints, mingling the characteristics of each parent in varying degrees, all the boys should be as fair-skinned and blue-eyed as their father, while the girls should altogether resemble their mothers. This would be thought strange enough, but the case of these butterflies is yet more extraordinary, for each mother is capable not only of producing male offspring like the father, and female like herself, but also other females like her fellow wife, and altogether differing from herself!

Seems like the text should be removed. Humanengr (talk) 21:59, 25 December 2018 (UTC)Reply

Update:

Now I see Darwin, twice in the last para starting on this page of Origin of Species:

There are, also, cases of dimorphism and trimorphism, both with animals and plants. Thus, Mr. Wallace, who has lately called attention to the subject, has shown that the females of certain species of butterflies, in the Malay archipelago, regularly appear under two or even three conspicuously distinct forms, not connected by intermediate varieties. …

It certainly at first appears a highly remarkable fact that the same female butterfly should have the power of producing at the same time three distinct female forms and a male; and that an hermaphrodite plant should produce from the same seed-capsule three distinct hermaphrodite forms, bearing three different kinds of females and three or even six different kinds of males. Nevertheless these cases are only exaggerations of the common fact that the female produces offspring of two sexes which sometimes differ from each other in a wonderful manner.

Someone is misreading Wallace — is it Darwin or is it me? Humanengr (talk) 22:15, 25 December 2018 (UTC)Reply

Further update:

From Once a Week, 1870: "In November, 1861, we find Mr. Wallace at Lobo Raman, in the centre of the east end of Sumatra. … A single brood of caterpillars is found to produce males as well as tailed and tailless females; and forms intermediate in character seem never to occur."

Humanengr (talk) 21:03, 26 December 2018 (UTC)Reply

Other examples of animal trimorphism

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[Collecting for consideration:]

In starting to search for early mentions of animal trimorphism, I see:

  1. 1888 (from Darwin, Wallace??) in Chamber's Encyclopœdia: A Dictionary of Universal Knowledge, Volume 2: "Equitidae (e.g., the common Papilio), in some cases with di- or trimorphic females."
  2. 1898 W.L.W. Field in an article on Lepidoptera here: "… dimorphic and trimorphic females are found in very many species."
  3. 1905 R. Shelford referencing work by Doubleday and Hewitson 1848, on p. 90 of A List of the Butterflies of Borneo, and Nymphalinae. Part II: "Euripus halitherses sub-sp. borneensis — … I believe that three fairly distinct female forms and three only can be recognized, viz: — …"
  4. 1927 Genetics in Relation to Agriculture: "Unisexual Polymorphism in Lepidoptera. In many species of butterflies in nature there are two or more distinct female types but only a single male type. More rarely the reverse condition is shown in which two or more distinct male types are opposed to a single female form. To this phenomenon the term unisexual polymorphism, has been given."
  5. 1954 Journal of Entomology: Taxonomy: "… provide the only instances in the family of trimorphic males."

and later:

  1. 2009: Mark Rowland: “We discovered a novel mating system in which the individual males of various species of beetles have the capacity to express one of three alternative morphologies … [more]”
  2. 2016: Gilbert: In trimorphic species of Asplanchna, females can vary in size and shape, from a small saccate morph to giant cruciform and campanulate morphs. In species that also reproduce sexually, diploid eggs can develop into two types of females…"

Corrections and additions welcome. Humanengr (talk) 20:48, 26 December 2018 (UTC)Reply