Extensive micro-geographical shell polymorphism in a planktotrophic marine intertidal snail

Cuña, V.; Saura, María; Quesada, Humberto; Rolán‐Alvarez, Emilio

doi:10.3354/meps09033

Cited by 8 publications

(6 citation statements)

References 86 publications

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“…This is particularly interesting because the shell size and shape differences existing between the RB and SU morphs have been previously interpreted in adaptive terms (reviewed in [ 4 ] for CS and RW1), for which a genetic basis with a small contribution from developmental plasticity has been demonstrated [ 5 , 19 , 48 , 49 ]. Additionally, two different snail species ( Nucella lapillus and Melarraphe neritoides ) showed a similar parallel trend in shell shape (RW1) across the same environmental cline [ 50 ]. The SRB morph lives in the most sheltered habitats and shows the most extreme sheltered morphological traits of all Galician morphotypes reported so far, displaying the largest shells and smallest apertures ( Fig 1 ).…”

Section: Discussionmentioning

confidence: 99%

Historical Biogeography of the Marine Snail Littorina saxatilis Inferred from Haplotype and Shell Morphology Evolution in NW Spain

et al. 2016

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The marine snail Littorina saxatilis exhibits extreme morphological variation between and within geographical regions and represents an excellent model for assessing local adaptation. Previous studies support the hypothesis of parallel evolution in sympatry of two morphologically different ecotypes (named as RB and SU) that co-inhabit different habitats from Galician rocky shores (NW Spain), and which are interrupted by sheltered areas inhabited by a different morph never studied before (named as SRB). Here, we use morphological and mitochondrial DNA (mtDNA) sequence data to test hypotheses on the origin and diversification of SRB snails and to assess their evolutionary relationships with RB and SU ecotypes. Our results show that the SRB morph displays the largest size and shell elongation and the smallest relative shell aperture, representing an extreme type of the RB vs. SU polymorphism, which has been linked to adaptation to sheltered ecological factors. Phylogenetic analysis shows that the SRB morph shares ancestry with RB and SU ecotypes, rejecting the hypothesis that the SRB morph marks relict populations from which these ecotypes evolved in Galician coasts. Our data support that genetic differentiation among SRB, RB and SU morphs results from a general pattern of restricted gene flow and isolation by distance linked to the colonization of Galician coasts by two independent mtDNA lineages, rather than from a random fragmentation of the initial distributional range. Therefore, the confinement of distinct lineages to specific geographical areas denote evident limits to the distances these snails can disperse. Morphological analysis indicates no association between mtDNA lineage and a specific morphotype, and suggests the independent gain of convergent morphological patterns within each mtDNA lineage in populations occupying contrasting habitats following the colonization of Galician coasts.

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Section: Discussionmentioning

confidence: 99%

Historical Biogeography of the Marine Snail Littorina saxatilis Inferred from Haplotype and Shell Morphology Evolution in NW Spain

et al. 2016

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“…CS; U1, degree of globosity; RW1, relative shell aperture) differences between RB and SU ecotypes can only be interpreted in adaptive terms (Carvajal‐Rodríguez et al ., ; Conde‐Padín et al ., , ). Moreover, two other polymorphisms of gastropod species ( Melarhaphe neritoides , Cuña et al ., ; García et al ., ; the dogwhelk Nucella lapillus , Guerra‐Varela et al ., ) affecting shell aperture (RW1) have been detected on the same shores and microhabitats as the RB and SU polymorphism. Hence, exogenous selection acting on shell traits might play an important role in the observed microhabitat distribution.…”

Section: Discussionmentioning

confidence: 99%

Selection on hybrids of ecologically divergent ecotypes of a marine snail: the relative importance of exogenous and endogenous barriers

Galindo

Rivas

Saura

et al. 2013

Biol J Linn Soc Lond

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Unravelling the form of selection acting on hybrids of ecotypes undergoing ecological speciation is essential to understand the mechanisms behind the evolution of reproductive isolation in the face of gene flow. Shell phenotype is known to be affected by natural selection and is involved in the fitness of the marine snail Littorina saxatilis. Here, we studied the association between shell traits and fitness in hybrids in order to determine the relative role of exogenous and endogenous selection in this hybrid zone of L. saxatilis. We show that directional selection is the predominant mode of selection among hybrids. We also show its heterogeneity, affecting different shell traits, within populations at the level of the microhabitat. Therefore, endogenous selection mechanisms are most probably lacking in this hybrid zone and exogenous barriers (pre‐ and post‐zygotic) are possibly one of the main forces behind the evolution of barriers to gene flow between these ecologically divergent ecotypes. This study shows how this barrier might represent an important type of reproductive isolation within ecological speciation, and this should be taken into account in future studies of speciation in hybrid zones. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 111, 391–400.

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“…The photoperiod was set to a 14/10-h light/dark cycle and the snails were able to graze on the algae growing on the nylon mesh during this time. Note that specimens of M. neritoides have been maintained alive (and showing shell growth) in similar conditions for 9 ( Cuña et al 2011 ) and 15 months ( García et al 2013 ), respectively.…”

Section: Methodsmentioning

confidence: 99%

“…At this intertidal level, M. neritoides is commonly sheltered in crevices to avoid desiccation ( Fretter and Manley 1977 ; Raffaelli and Hughes 1978 ; Britton 1995 ) and can be exposed to emersion for weeks ( Britton 1992 ); it is proven to survive this stress for at least 5 months ( Lysaght 1941 ). Lower shore and high-shore subpopulations from the same locality have been found to be morphologically different (shell size and shape) although they lacked genetic differentiation based on AFLPs (amplified fragment length polymorphisms) ( Cuña et al 2011 ). In contrast, these morphologically different subpopulations (morphs) showed significant differences at the proteome level (22%) when exposed to a common laboratory environment, suggesting a certain level of phenotypic plasticity in this species ( García et al 2013 ).…”

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confidence: 99%

Limited proteomic response in the marine snailMelarhaphe neritoidesafter long-term emersion

et al. 2017

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Rocky intertidal organisms are commonly exposed to environmental gradients, promoting adaptations to these conditions. Emersion time varies along the intertidal range and in the supralittoral zone is frequently larger than a single tidal cycle, even lasting for weeks. The planktonic-dispersing gastropod Melarhaphe neritoides is a common species of the high shore, adapted to reduce water loss in order to survive during long-term emersion. In this study, we investigated the molecular response, at the proteome level, of M. neritoides collected in high-shore tide pools to a series of emersion periods, from 8 to 24 days, in laboratory conditions. We compared this response to individuals maintained submerged during this period, because this was their original habitat. We also included a reversion treatment in the study, in which emersed individuals were returned to the submerged conditions. Although we detected an increase in overall protein concentration with longer emersion periods, contrary to general expectation, the two dimensional electrophoresis (2DE)-based proteomic analysis did not show significant differences between the treatments at the level of individual protein spots, even after an emersion period of 24 days. Our results suggest that the metabolism remains unaltered independent of the treatment carried out or the changes are very subtle and therefore difficult to detect with our experimental design. We conclude that M. neritoides could be equally adapted to emersion and submersion without drastic physiological changes.

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Extensive micro-geographical shell polymorphism in a planktotrophic marine intertidal snail

Cited by 8 publications

References 86 publications

Historical Biogeography of the Marine Snail Littorina saxatilis Inferred from Haplotype and Shell Morphology Evolution in NW Spain

Historical Biogeography of the Marine Snail Littorina saxatilis Inferred from Haplotype and Shell Morphology Evolution in NW Spain

Selection on hybrids of ecologically divergent ecotypes of a marine snail: the relative importance of exogenous and endogenous barriers

Limited proteomic response in the marine snailMelarhaphe neritoidesafter long-term emersion

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