Summary
Partula suturalis is unusual among snails in being polymorphic for direction of shell coiling. Polymorphic populations of P. suturalis occur in narrow clines between areas of monomorphic dextral or sinistral populations. The distribution of dextral populations coincides with the distribution of the sinistral species P. mooreana, P. tohiveana and P. Olympia suggesting character displacement for reproductive isolation. Chirality affects courtship behaviour, and no-choice mating experiments show that pairs with opposite coil mate only 20 per cent as frequently as do pairs with the same coil. Fewer young are produced by these mixed pairs. Fertilities of dextral and sinistral P. suturalis are the same in a population composed of equal frequencies of the two morphs. However, among wild-caught snails from a population in which sinistrals occur at low frequency, the rare morph produces fewer young than the common morph. The effects of chirality on behavioural isolation result in selection against the rare morph, accounting for the rarity of polymorphic populations. Such positive frequency dependent selection is capable of maintaining the stability of hybrid zones.
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Brown, K S, Sheppard, P M, and Turner, J R G. 1974. Quaternary refugia in tropical America: evidence from race formation in Heliconius butterflies. Proc R Soc Lond B, 187, 369–378.
Clarke, B. 1968. Balanced polymorphism and regional differentiation in land snails. In Drake, E. T. (ed.) Evolution and Environment, Yale University Press, New Haven, pp. 351–368.
Clarke, B, and Murray, J. 1969. Ecological genetics and speciation in land snails of the genus Partula. Biol J Linn Soc, London, 1, 31–42.
Clarke, B, Arthur, W, Horsley, D T, and Parkin, D T. 1978. Genetic variation and natural selection in pulmonate molluscs. In Fretter, V., and Peake, J. (eds.) Pulmonates, Vol. 2A, Academic Press, New York, pp. 219–270.
Crampton, H E. 1916. Studies on the variation, distribution, and evolution of the genus Partula. The species inhabiting Tahiti. Carnegie Inst Washington Publ, 228, 1–311.
Crampton, H E. 1932. Studies on the variation, distribution, and evolution of the genus Partula. The species inhabiting Moorea. Carnegie Inst Washington Publ, 410, 1–335.
Johnson, M S. 1976. AUozymes and area effects in Cepaea nemoralis on the western Berkshire Downs. Heredity, 36, 105–121.
Jones, J S, Selander, R K, and Schnell, G D. 1980. Patterns of morphological and molecular polymorphism in the land snail Cepaea nemoralis. Biol J Linn Soc, London, 14, 359–387.
Lipton, C S, and Murray, J. 1979. Courtship of land snails of the genus Partula. Malacologia, 19, 129–146.
Moore, W S. 1977. An evaluation of narrow hybrid zones in vertebrates. Quart Rev Biol, 52, 263–277.
Moore, W S. 1979. A single locus mass-action model of assortative mating, with comments on the process of speciation. Heredity, 42, 173–186.
Moore, W S. 1981. Assortative mating genes selected along a gradient. Heredity, 46, 191–195.
Murray, J, and Clarke, B. 1966. The inheritance of polymorphic shell characters in Partula (Gastropoda). Genetics, 54, 1261–1277.
Murray, J, and Clarke, B. 1968. Partial reproductive isolation in the genus Partula (Gastropoda) on Moorea. Evolution, 22, 684–698.
Murray, J, and Clarke, B. 1976. Supergenes in polymorphic land snails. II. Partula suturalis. Heredity, 37, 271–282.
Murray, J, and Clarke, B. 1980. The genus Partula on Moorea: speciation in progress. Proc R Soc Lond B, 211, 83–117.
Turner, J R G. 1971. Two thousand generations of hybridisation in a Heliconius butterfly. Evolution, 25, 471–482.
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Johnson, M. Polymorphism for direction of coil in Partula suturalis: Behavioural isolation and positive frequency dependent selection. Heredity 49, 145–151 (1982). https://doi.org/10.1038/hdy.1982.80
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DOI: https://doi.org/10.1038/hdy.1982.80
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