Population structure and coil dimorphism in a tropical land snail

Schilthuizen , Menno and Scott, B. J. and Cabanban, A. S. and Craze, P. G. (2005) Population structure and coil dimorphism in a tropical land snail. Heredity, 95 (3). pp. 216-220. ISSN 0018-067X

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Official URL: http://dx.doi.org/10.1038/sj.hdy.6800715

Abstract

Tree snails of the subgenus Amphidromus s. str. are unusual because of the chiral dimorphism that exists in many species, with clockwise ( dextrally) and counter-clockwise ( sinistrally) coiled individuals co-occurring in the same population. Given that mating in snails is normally impeded when the two partners have opposite coil, positive frequency-dependent selection should prevent such dimorphism from persisting. We test the hypothesis that a strong population structure with little movement between tree-based demes may result in the fixation of coiling morphs at a very small spatial scale, but apparent dimorphism at all larger scales. To do so, we describe the spatial structure in a Malaysian population of A. inversus ( Muller, 1774) with 36% dextrals. We marked almost 700 juvenile and adult snails in a piece of forest consisting of 92 separate trees, and recorded dispersal and the proportions of dextrals and sinistrals in all trees over a 7-day period. We observed frequent movement between trees ( 155 events), and found that no trees had snail populations with proportions of dextrals and sinistrals that were significantly different from random. Upon recapture 1 year later, almost two-thirds of the snails had moved away from their original tree. We conclude that population structure alone cannot stabilise the coil dimorphism in Amphidromus.

Item Type:Article
Uncontrolled Keywords:Gene flow, Frequency-dependent selection, Fixation, chirality, Camaenidae
Subjects:?? QL360-599.82 ??
Divisions:SCHOOL > Institute for Tropical Biology and Conservation
ID Code:1080
Deposited By:IR Admin
Deposited On:14 Oct 2011 13:59
Last Modified:23 Feb 2015 10:10

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