A gastropod color polymorphism: one adaptive strategy of phenotypic variation
TLDR
A case of shell color ploymorphism in the shallow water mesogastropod Crepidula convexa is described, where the necessary and sufficient criteria for a stable polymorphism are met, but reasons are set forth for believing that this is, rather, a case of unstable polymorphism.Abstract:
A case of shell color ploymorphism in the shallow water mesogastropod Crepidula convexa is described. Polymorphism of color in C. convexa appears to be based on disruptive selection, which occurs due to the availability of two contrasting shades of substrate, heterogeneous in time and space, combined with mortality from visual predators.Data on the relative survival of the two phentoypes of C. convexa in two patches of a heterogeneous environment are applied to the fitness set model developed by Levins (1968). The necessary and sufficient criteria for a stable polymorphism are met, but reasons are set forth for believing that this is, rather, a case of unstable polymorphism.Only one other species of the genus, C. adunca, shows a similar color polymorphism. Ecological factors uniquely shared by the two species are: visibility of inherited shell color, a major part of the population living in the intertidal zone, and an impact by visual predators. Color polymorphism is correlated with visual predation on a ...read more
Citations
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Molluscan shell colour
TL;DR: It is suggested that pigments appear to be distributed in a phylogenetically relevant manner and that the synthesis of colour is likely to be energetically costly.
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Physiological stress and color polymorphism in the intertidal snail nucella lapillus.
TL;DR: The intertidal snail Nucella lapillus exhibits considerable variation in shell color both within and between populations differentially exposed to wave action, and the role of physiological stress and selective predation is determined.
Journal ArticleDOI
Evidence for genetic control of pigmentation of shell and mantle edge in selected families of Pacific oysters, Crassostrea gigas
TL;DR: Three experimental cohorts of pedigreed oysters, each having gone through one or two generations of selection, were investigated for both shell and mantle edge pigmentation, finding the traits to be complex and best described as continuous.
Journal ArticleDOI
A Novel Shell Color Variant of the Pacific Abalone Haliotis Discus Hannai Ino Subject to Genetic Control and Dietary Influence
TL;DR: It is demonstrated that shell color in Pacific abalone is subject to genetic control as well as dietary modification, and the latter probably offers selective advantages in camouflage and predator avoidance.
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Natural selection for apostasy and crypsis acting on the shell colour polymorphism of a mangrove snail, Littoraria filosa (Sowerby) (Gastropoda: Littorinidae)
TL;DR: By manipulating the colour frequencies of subpopulations of small snails isolated on individual trees, it was shown that the disappearance of yellow and brown shells was frequency-dependent, consistent with hypotheses of mimicry of background elements by the morphs and of apostatic selection by unknown predators.
References
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BookDOI
Evolution in Changing Environments: Some Theoretical Explorations. (MPB-2)
TL;DR: Professor Levins, one of the leading explorers in the field of integrated population biology, considers the mutual interpenetration and joint evolution of organism and environment, occurring on several levels at once.
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Genetic Equilibrium When More Than One Ecological Niche is Available
TL;DR: The question arose of whether it was in fact possible to have equilibrium without the heterozygote being superior to both homozygotes in any single niche and it is shown below that under certain assumptions the answer is yes.
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The Pisaster-Tegula Interaction: Prey Patches, Predator Food Preference, and Intertidal Community Structure
TL;DR: Analysis of relative growth and reproduction indicates that beyond a certain size (16 mm) large individuals perform less well in the upper than those in the lower intertidal zone, and the zoogeographic homogeneity of the Pacific rocky coastline community are discussed in relation to three intermeshing ecological processes.
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Selection in the polymorphic land snail Cepaea nemoralis.
TL;DR: An investigation into the problem of the relative importance of selection and drift in determining the distribution of different colour and banding patterns in C. nemoralis finds that they have definite selective values, related to the environment, determining the general aspect of different populations and therefore of their gene ratios.