Articulated coralline algae of the genus Amphiroa are highly effective natural inducers of settlement in the tropical abalone Haliotis asinina. (73/336)

The initiation of metamorphosis in marine invertebrates is strongly linked to the environment. Planktonic larvae typically are induced to settle and metamorphose by external cues such as coralline algae (Corallinaceae, Rhodophyta). Although coralline algae are globally abundant, invertebrate larvae of many taxa settle in response to a very limited suite of species. This specificity impacts population structure, as only locations with the appropriate coralline species can attract new recruits. Abalone (Gastropoda, Haliotidae) are among those taxa in which closely related species are known to respond to different coralline algae. Here we identify highly inductive natural cues of the tropical abalone Haliotis asinina. In contrast to reports for other abalone, the greatest proportion of H. asinina larvae are induced to settle and metamorphose (92.8% to 100% metamorphosis by 48 h postinduction) by articulated corallines of the genus Amphiroa. Comparison with field distribution data for different corallines suggests larvae are likely to be settling on the seaward side of the reef crest. We then compare the response of six different H. asinina larval families to five different coralline species to demonstrate that induction by the best inductive cue (Amphiroa spp.) effectively extinguishes substantial intraspecific variation in the timing of settlement.  (+info)

Organic-inorganic interfaces and spiral growth in nacre. (74/336)

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Oceaniserpentilla haliotis gen. nov., sp. nov., a marine bacterium isolated from haemolymph serum of blacklip abalone. (75/336)

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A genome-scan method to identify selected loci appropriate for both dominant and codominant markers: a Bayesian perspective. (76/336)

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Different functions for homologous serotonergic interneurons and serotonin in species-specific rhythmic behaviours. (77/336)

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Individual growth of Heleobia piscium in natural populations (Gastropoda: Cochliopidae) from the multiple use natural Reserve Isla Martin Garcia, Buenos Aires, Argentina. (78/336)

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Evolution of the Toxoglossa venom apparatus as inferred by molecular phylogeny of the Terebridae. (79/336)

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Phenotypic plasticity and sexual dimorphism in size at post-juvenile metamorphosis: common-garden rearing of an intertidal gastropod with determinate growth. (80/336)

Proximate factors of the intraspecific variation in molluscan shell morphology have long received attention in biology. The intertidal gastropod Monetaria annulus (Mollusca; Gastropoda; Cypraeidae) is particularly suitable for the study of variation in body size, because this species is a determinate grower in the sense that soft-body size shows no further increase after the juvenile stage. Cross-sectional field surveys on post-juvenile individuals have indicated that the mean body size varies widely among populations and is larger in females than in males within populations. To examine whether these patterns are due to genetic differences, we conducted a common-garden rearing experiment with juvenile individuals collected from two populations on Okinawa Island. After adjusting for among-individual differences in initial degree of development, statistical analyses revealed that this species exhibits female-biased sexual size dimorphism mediated by a longer development time rather than by faster growth rates in females. Although wild individuals show a remarkable size difference between populations, no size difference was found between the populations in the individuals reared in a common-garden condition. This result suggests that the among-population size difference does not have a genetic basis and is caused by phenotypic plasticity based on environmental heterogeneity among habitats.  (+info)