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Spatial geographic mosaic in an aquatic predator-prey network.

Chaves-Campos J, Johnson SG, Hulsey CD - PLoS ONE (2011)

Bottom Line: The geographic mosaic theory of coevolution predicts 1) spatial variation in predatory structures as well as prey defensive traits, and 2) trait matching in some areas and trait mismatching in others mediated by gene flow.The variation in crushing resistance among populations was not explained by geographic proximity or by genetic similarity in any species.We detected clear phylogeographic patterns and limited gene flow for the snails but not for the fish.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, University of New Orleans, New Orleans, Louisiana, United States of America.

ABSTRACT
The geographic mosaic theory of coevolution predicts 1) spatial variation in predatory structures as well as prey defensive traits, and 2) trait matching in some areas and trait mismatching in others mediated by gene flow. We examined gene flow and documented spatial variation in crushing resistance in the freshwater snails Mexipyrgus churinceanus, Mexithauma quadripaludium, Nymphophilus minckleyi, and its relationship to the relative frequency of the crushing morphotype in the trophically polymorphic fish Herichthys minckleyi. Crushing resistance and the frequency of the crushing morphotype did show spatial variation among 11 naturally replicated communities in the Cuatro Ciénegas valley in Mexico where these species are all endemic. The variation in crushing resistance among populations was not explained by geographic proximity or by genetic similarity in any species. We detected clear phylogeographic patterns and limited gene flow for the snails but not for the fish. Gene flow among snail populations in Cuatro Ciénegas could explain the mosaic of local divergence in shell strength and be preventing the fixation of the crushing morphotype in Herichthys minckleyi. Finally, consistent with trait matching across the mosaic, the frequency of the fish morphotype was negatively correlated with shell crushing resistance likely reflecting the relative disadvantage of the crushing morphotype in communities where the snails exhibit relatively high crushing resistance.

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Relationship between shell length and crushing resistance (both log transformed) in Mexipyrgus churinceanus (Mc), Mexithauma quadripaludium (Mq), and Nymphophilus minckleyi (Nm).The best linear fit is shown for illustrative purposes (solid black line).
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pone-0022472-g003: Relationship between shell length and crushing resistance (both log transformed) in Mexipyrgus churinceanus (Mc), Mexithauma quadripaludium (Mq), and Nymphophilus minckleyi (Nm).The best linear fit is shown for illustrative purposes (solid black line).

Mentions: Average crushing resistance spanned a range of approximately 50 N among populations for very similarly sized snails (about 5 mm) of the same species (Table 1). Differences among populations were significant in each species (ANOVA: F10, 215 = 42.7, P<0.0001 for Mexipyrgus churinceanus, F10, 209 = 5.05, P<0.0001 for Mexithauma quadripaludium and F10, 210 = 6.55, P<0.0001 for Nymphophilus minckleyi). Post-hoc multiple comparison revealed that most populations differed from each other in the case of Mexipyrgus churinceanus, while only some populations differed from each other in the other two species (Table S2). In general, localities with low average crushing resistance, such as Juan Santos and Churince, were significantly different from places with high average crushing resistance, such as the two Tío Cándido sites and Tierra Blanca. Crushing resistance varied with shell length in Nymphophilus minckleyi and Mexipyrgus churinceanus but not in Mexithauma quadripaludium (Fig. 3). Crushing resistance varied among populations when adjusted by shell length in the former two species (ANCOVA: F10,214 = 14.8, P<0.0001 for Mexipyrgus churinceanus; F10,209 = 4.9, P<0.0001 for Nymphophilus minckleyi). The differences detected using multiple comparisons with size-adjusted crushing resistance values resembled those found with raw values of crushing resistance (Table S2). Interestingly, several pools separated by less than 1 km from each other and located in the same drainage, such as Mojarral Este Alta and Mojarral Este Baja had snails with different size-adjusted shell strength (especially for Mexipyrgus churinceanus and Nymphophilus minckleyi). On the other hand, snails located in different drainages and far away from each other, such as Churince and Los Remojos Blanco exhibited very similar crushing resistance in these same species (Tables 1 and 2, Fig. 1).


Spatial geographic mosaic in an aquatic predator-prey network.

Chaves-Campos J, Johnson SG, Hulsey CD - PLoS ONE (2011)

Relationship between shell length and crushing resistance (both log transformed) in Mexipyrgus churinceanus (Mc), Mexithauma quadripaludium (Mq), and Nymphophilus minckleyi (Nm).The best linear fit is shown for illustrative purposes (solid black line).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3140530&req=5

pone-0022472-g003: Relationship between shell length and crushing resistance (both log transformed) in Mexipyrgus churinceanus (Mc), Mexithauma quadripaludium (Mq), and Nymphophilus minckleyi (Nm).The best linear fit is shown for illustrative purposes (solid black line).
Mentions: Average crushing resistance spanned a range of approximately 50 N among populations for very similarly sized snails (about 5 mm) of the same species (Table 1). Differences among populations were significant in each species (ANOVA: F10, 215 = 42.7, P<0.0001 for Mexipyrgus churinceanus, F10, 209 = 5.05, P<0.0001 for Mexithauma quadripaludium and F10, 210 = 6.55, P<0.0001 for Nymphophilus minckleyi). Post-hoc multiple comparison revealed that most populations differed from each other in the case of Mexipyrgus churinceanus, while only some populations differed from each other in the other two species (Table S2). In general, localities with low average crushing resistance, such as Juan Santos and Churince, were significantly different from places with high average crushing resistance, such as the two Tío Cándido sites and Tierra Blanca. Crushing resistance varied with shell length in Nymphophilus minckleyi and Mexipyrgus churinceanus but not in Mexithauma quadripaludium (Fig. 3). Crushing resistance varied among populations when adjusted by shell length in the former two species (ANCOVA: F10,214 = 14.8, P<0.0001 for Mexipyrgus churinceanus; F10,209 = 4.9, P<0.0001 for Nymphophilus minckleyi). The differences detected using multiple comparisons with size-adjusted crushing resistance values resembled those found with raw values of crushing resistance (Table S2). Interestingly, several pools separated by less than 1 km from each other and located in the same drainage, such as Mojarral Este Alta and Mojarral Este Baja had snails with different size-adjusted shell strength (especially for Mexipyrgus churinceanus and Nymphophilus minckleyi). On the other hand, snails located in different drainages and far away from each other, such as Churince and Los Remojos Blanco exhibited very similar crushing resistance in these same species (Tables 1 and 2, Fig. 1).

Bottom Line: The geographic mosaic theory of coevolution predicts 1) spatial variation in predatory structures as well as prey defensive traits, and 2) trait matching in some areas and trait mismatching in others mediated by gene flow.The variation in crushing resistance among populations was not explained by geographic proximity or by genetic similarity in any species.We detected clear phylogeographic patterns and limited gene flow for the snails but not for the fish.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, University of New Orleans, New Orleans, Louisiana, United States of America.

ABSTRACT
The geographic mosaic theory of coevolution predicts 1) spatial variation in predatory structures as well as prey defensive traits, and 2) trait matching in some areas and trait mismatching in others mediated by gene flow. We examined gene flow and documented spatial variation in crushing resistance in the freshwater snails Mexipyrgus churinceanus, Mexithauma quadripaludium, Nymphophilus minckleyi, and its relationship to the relative frequency of the crushing morphotype in the trophically polymorphic fish Herichthys minckleyi. Crushing resistance and the frequency of the crushing morphotype did show spatial variation among 11 naturally replicated communities in the Cuatro Ciénegas valley in Mexico where these species are all endemic. The variation in crushing resistance among populations was not explained by geographic proximity or by genetic similarity in any species. We detected clear phylogeographic patterns and limited gene flow for the snails but not for the fish. Gene flow among snail populations in Cuatro Ciénegas could explain the mosaic of local divergence in shell strength and be preventing the fixation of the crushing morphotype in Herichthys minckleyi. Finally, consistent with trait matching across the mosaic, the frequency of the fish morphotype was negatively correlated with shell crushing resistance likely reflecting the relative disadvantage of the crushing morphotype in communities where the snails exhibit relatively high crushing resistance.

Show MeSH
Related in: MedlinePlus