Character Displacement in Polyphenic Tadpoles

Pfennig, David W.; Murphy, Peter

doi:10.1111/j.0014-3820.2000.tb00717.x

Cited by 118 publications

(185 citation statements)

References 37 publications

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“…1). Several studies recently have reported different reaction norms in populations occupying habitats with different levels of selection (Pfennig & Murphy, 2000;Laurila et al, 2002;Trussell & Nicklin, 2002). Different plastic responses, or different reaction norms between populations, provide good evidence that those different responses are adaptive (Laurila et al, 2002).…”

Section: Discussionmentioning

confidence: 99%

“…A positive relationship between plasticity in the frequency of the broad headed morph and egg size would provide necessary evidence for adaptive integration of plasticity and egg size and support the idea of coadaptation (Doughty 2002). However, natural selection can act on morphological plasticity and trophic polyphenism (Moran 1992), driving evolution of different reaction norms among populations (Pfennig & Murphy, 2000;Laurila et al, 2002;Trussell & Nicklin, 2002). Plasticity in the frequency of the broad-headed morph among natural populations may be caused by the adaptive response of the plasticity itself, which would support the idea that plasticity and egg size are optimized independently.…”

Section: Introductionmentioning

confidence: 86%

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Maternal effects on phenotypic plasticity in larvae of the salamander Hynobius retardatus

et al. 2009

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Maternal effects are widespread and influence a variety of traits, for example, life history strategies, mate choice and capacity to avoid predation. Therefore, maternal effects may also influence phenotypic plasticity of offspring, but few studies have addressed the relationship between maternal effects and phenotypic plasticity of offspring. We examined the relationship between a maternally influenced trait (egg size) and the phenotypic plasticity of the induction rate of the broad-headed morph in the salamander Hynobius retardatus. The relationship between egg size and the induction of the broad-headed morph was tested across experimental crowding conditions (densities of low conspecifics, high conspecifics, and high heterospecific anuran), using eggs and larvae from eight natural populations with different larval densities of conspecifics and heterospecifics. The broad-headed morph has a large mouth that enables it to consume either conspecifics or heterospecifics, and this ability gives survival advantages over the normal morph. We have determined that there is phenotypic plasticity in development, as shown by an increase in the frequency of broad-headed morph in response to an increase in the density of conspecifics and heterospecifics. This reaction norm differed between populations. We also determined that the frequency of the broad-headed morph is affected by egg size in which larger egg size resulted in expression of the broad-headed morph. Furthermore, we determined that selection acting on the propensity to develop the broad-headed morph has produced a change in egg size. Lastly, we found that an increase in egg size alters the reaction norm to favor development of the broad-headed morph. For example, an equal change in experimental density produces a greater change in the frequency of the broad-headed morph in larvae developing from large eggs than it does in larvae developing from small eggs. Population differences in plasticity might be the results of differences in egg 3 size between populations, which is caused by the adaptive integration of the plasticity and egg size. Phenotypic plasticity can not evolve independently of maternal effects.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 86%

Maternal effects on phenotypic plasticity in larvae of the salamander Hynobius retardatus

et al. 2009

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“…However, intensive studies of young species in other groups of organisms including Anolis lizards on Caribbean islands (Losos 2009), spadefoot toad tadpoles in the American southwest (Pfennig and Murphy 2000), and Darwin's finches on Galápagos islands (Grant and Grant 2006), have uncovered similar mechanisms, suggesting that they occur widely (though not necessarily universally). Competition and coevolution are likely to be major drivers of species differentiation in nature.…”

Section: Discussionmentioning

confidence: 99%

“…For these reasons, evaluating the role of competition and coevolution in the evolution of diversity must go beyond pattern to illuminate the mechanisms driving divergence. Intensive recent research on a few systems, including Darwin's finches (Grant and Grant 2006), spadefoot toads (Pfennig and Murphy 2000), Caribbean island lizards (Losos 2009) and threespine stickleback (Schluter and McPhail 1992;Schluter 2003) have helped to build a more comprehensive picture of the role of competition and coevolution. In this article, I give an overview of progress from studies of one of these groups, the threespine stickleback of small coastal lakes in British Columbia, Canada.…”

Section: Introductionmentioning

confidence: 99%

Resource Competition and Coevolution in Sticklebacks

Schluter¹

2010

Evo Edu Outreach

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Threespine stickleback in young postglacial lakes provide a compelling example of coevolution between species that compete for resources. Coexisting pairs of stickleback species are highly divergent in habitat, diet, and body size and shape, whereas stickleback occurring alone in lakes are intermediate. We used experiments in ponds to test mechanisms of divergence between coexisting species. The results support the hypothesis of coevolution by resource competition between stickleback, but we found evidence that interactions with natural enemies also contribute to divergence. Natural selection arising from these interactions selects against intermediate phenotypes, included hybrids, and thus has contributed to the origin and persistence of stickleback species.

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“…Tadpoles were not fed natural live food (e.g., fairy shrimp), because doing so can induce the production of carnivore-morph tadpoles, which potentially cannibalize other tadpoles (reviewed in Pfennig and Murphy 2000). Live food can enhance development times of spadefoots (Simovich 1985;Simovich et al 1991), however, so our measures of development times on fish food are potentially conservative (see Discussion for comparison of our results to other studies).…”

Section: Experimental Crossesmentioning

confidence: 90%

Differential Selection to Avoid Hybridization in Two Toad Species

Pfennig

Simovich

2002

Evolution

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Abstract. The fitness consequences of hybridization critically affect the speciation process. When hybridization is costly, selection favors the evolution of prezygotic isolating mechanisms (e.g., mating behaviors) that reduce heterospecific matings and, consequently, enhance reproductive isolation between species (a process termed reinforcement). If, however, selection to avoid hybridization differs between species, reinforcement may be impeded. Here, we examined both the frequency and fitness effects of hybridization between plains spadefoot toads (Spea bombifrons) and New Mexico spadefoot toads (S. multiplicata). Hybridization was most frequent in smaller breeding ponds that tend to be ephemeral, and heterospecific pairs consisted almost entirely of S. bombifrons females and S. multiplicata males. Moreover, in controlled experimental crosses, hybrid offspring from crosses in which S. multiplicata was maternal had significantly lower survival and longer development time than pure S. multiplicata offspring. By contrast, hybrid offspring from crosses in which S. bombifrons was maternal outperformed pure S. bombifrons offspring by reaching metamorphosis faster. These data suggest that, although S. multiplicata females are under selection to avoid hybridization, selection might favor those S. bombifrons females that hybridize with S. multiplicata if their breeding pond is highly ephemeral. Generally, the strength of selection to avoid hybridization may differ for hybridizing species, possibly impeding reinforcement. Speciation by reinforcement is a potentially important means by which populations become reproductively isolated. When hybridization by two sympatric species produces offspring that have lower fitness than pure-species types, selection can lead to the evolution of premating isolating barriers (e.g., mating behaviors) that reduce hybridization

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Character Displacement in Polyphenic Tadpoles

Cited by 118 publications

References 37 publications

Maternal effects on phenotypic plasticity in larvae of the salamander Hynobius retardatus

Maternal effects on phenotypic plasticity in larvae of the salamander Hynobius retardatus

Resource Competition and Coevolution in Sticklebacks

Differential Selection to Avoid Hybridization in Two Toad Species

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