Not All Character Convergence Is Competitive Mimicry

Not All Character Convergence Is Competitive Mimicry

SHORT COMMUNICATIONS 553 King reds.], Avian biology. Vol. 1. Academic cal taxonomy. W. H. Freeman and Co., San Press, New York. Francisco. SIBLEY, C. G. 1960. The electrophoretic patterns STORER, R. W. 1971. Classification of birds, pp. of avian egg-white proteins as taxonomic charac- 1-18. In D. S. Farner, and J. R. King leds.1, ters. Ibis 102:215-284. Avian biology. Vol. 1. Academic Press, New SIBLEY, C. G., AND J. E. AHLQUIST. 1972. A com- York. parative study of the egg-white proteins of non- passerine birds. Peabody Mus. Nat. Hist. Bull. Department of Zoology and StovuZZ Museum, Uni- no. 39. versity of Oklahoma, Norman, Oklahoma 73069. Ac- SNEATH, P. H. A., AND R. R. SOKAL. 1973. Numeri- cepted for publication 25 May 1976. SIMILARITY OF A TYRANT- insect-eaters thin bills, etc. There are also many other types of character convergence, some of them called FLYCATCHER AND A SILKY- “mimicry.” FLYCATCHER: NOT ALL CHARACTER Cody (1973. Ann. Rev. Syst. Ecol. 4: 189-211), CONVERGENCE IS COMPETITIVE however, restricted the term “character convergence” to one type of convergence in appearance: that seen MIMICRY where different species become more alike in com- petitively excluding each other in zones of overlap. “character convergence” is not suf- EDWIN 0. WILLIS However, his ficently unambiguous to describe this type of con- vergence, which has all the characteristics of the The standard example of convergent appearance in types of character convergence normally called “mim- birds, Eastern Meadowlarks (Sturnellu magna) of icry.” I suggest that what Cody called “character the New World and Yellow-throated Longclaws convergence” is best referred to as “convergent (Macronyr croceus ) of Africa, has been widely used character displacement” (Grant, Biol. J. Linn. Sot. in text-books (for example, R. E. Ricklefs, Ecology, London 4 :39-68, 1972) or, more specifically, as Chiron Press, Newton, Mass., 1973: p. 342). The “competitive mimicry.” This is in line with previous Crested Black-tyrant (Knipolegus lophotes), a tyrant- ornithological use of “aggressive mimicry” (Willis, flycatcher of open scrub and dry areas in eastern Condor 65: 313-317, 1963) and “social mimicry” South America, is equally convergent to the unrelated (Moynihan, Evolution 122: 315-331, 1968). Cody, Phainopepla (Phuinopeplu nitens) of open scrub and indeed, compared his phenomenon directly with what dry areas of western North America, but the resem- otherwise is in danger of becoming “Moynihanian blance does not seem to have been noted before. mimicry.” Both species are crested, glossy-black, slender and Moynihan and Cody were separately led to use upright birds with red eyes, with large white patches the term “character convergence” in attempts to con- flashing at the bases of primaries in flight. Both flit trast first social mimicry and then competitive mim- from high in one small tree or bush to another in icry with “character displacement” (Brown and rather open areas, capturing insects in the air at Wilson, Syst. Zool. 5: 48-64, 1956). In character times and eating small fruits at other times. The displacement, one or more organisms evolve away Black-tyrants I have seen do well in scrubby pas- from or toward each other in morphological characters tures, in scattered trees around ranch houses, and in and near a zone of overlap (Grant, 1972). The in semi-open “cerrado” vegetation from Caparao to term is reasonably appropriate and descriptive Furnas in the eastern part of the state of Minas (though various types of mimicry and the phenom- Gerais, Brazil, but are less common in wetter de- enon of predator-selected aspect diversity also seem forested regions in the state of Sao Paulo. Small character displacement ), but divergent character dis- groups, pairs or single birds wander through such placement is only one type of “character divergence” areas, much as do Phainopeplas in Arizona. Their -which includes simple adaptive radiation in al- mainly highland black relatives, KnipoZegus uterrimus lopatry or otherwise. Character convergence, being and K. cyunirostris, are progressively less like Phai- more or less the opposite of character divergence, nopeplas. should not be used as the opposite of “character Since there are few characters to point out in displacement.” Grant (1972) used “character re- nearly-black birds, the resemblance of K. Zophotes lease” instead, a reasonable suggestion. to P. nitens is unlikely to supplant the meadowlark- I appreciate the help of Yoshika Oniki in prepara- longclaw example in textbooks. However, the con- tion of this note. vergence brings up the point that various types of habitat-induced convergences of characters are com- Depatiumento de Zoologiu, Universidade Estaduul de mon phenomena: unrelated grassland birds are often Cumpinas, Caixa Postal No. 1170, 13.100 Campinas, streaked; black and white patterns are common in Scio PUUZO, BrasiZ. Accepted for publication 28 June forest-edge birds; seed-eaters have thick bills and 1976. .

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