My Paramecium Study, Retrospect and Prospect

Hiwatashi, Koichi

doi:10.2108/zsj.18.1

Cited by 2 publications

(1 citation statement)

References 27 publications

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“…Cells began conjugating within a day, and we collected adjoined conjugates and isolated them into new tubes. As Paramecium exconjugates (the term for individual cells post conjugation) are genetically identical (Ahsan et al, 2022; Bell, 1989; Hiwatashi, 2001), individuals descended from the conjugating pair are clones with the potential to be genetically different from clonal lines that descend from other exconjugant pairs through both recombination and genetic differences among conjugating individuals. We established 132 of these outcrossed and now clonally propagated lines and maintained them on lettuce media.…”

Section: Methodsmentioning

confidence: 99%

Heritable intraspecific variation among prey in size and movement interact to shape predation risk and potential natural selection

Coblentz,

Yang,

Dalal

et al. 2024

Preprint

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Species' traits affect consumer-resource interactions with consequences for population dynamics, food webs, and energy flows through ecosystems. Yet, our expectations for how the strengths of consumer-resource interactions scale with species' traits largely come from interspecific comparisons. It remains unclear whether these interspecific associations hold for intraspecific trait variation among individuals that is subject to natural selection. Few studies have evaluated the heritability of prey traits related to predation risk and their potential genetic correlations to evaluate how selection might operate on intraspecific variation underlying predator-prey interactions. We used outcrossed and then clonally propagated lines of the ciliate Paramecium caudatum to examine variation in morphology and movement behavior, the extent to which this variation was heritable, and how intraspecific differences among lines altered Paramecium susceptibility to predation by the copepod Macrocyclops albidus. We found that the Paramecium lines exhibited heritable variation in body size and movement traits. In contrast to interspecific allometric relationships, body size and movement speed did not covary among clonal lines. The proportion of Paramecium consumed by copepods was positively associated with Paramecium body size and velocity as one might expect from interspecific relationships . However, we also found evidence of an interaction such that greater velocities led to greater predation risk for large body-sized paramecia but did not alter predation risk for smaller body-sized paramecia. The proportion of paramecia consumed was not related to copepod body size. These patterns of predation risk and heritable trait variation in paramecia suggest that copepod predation may act as a selective force that could operate independently on movement speed and body size with the strongest selection against large, high-velocity paramecia. Overall, our results indicate that conclusions drawn from relationships among species in traits and the strengths of consumer-resource interactions need not hold within species. Furthermore, patterns of genetic variation and covariation in traits coupled with their relationships to predation risk can lead to patterns of potential natural selection that would be hard to infer from interspecific patterns alone.

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Section: Methodsmentioning

confidence: 99%

Heritable intraspecific variation among prey in size and movement interact to shape predation risk and potential natural selection

Coblentz,

Yang,

Dalal

et al. 2024

Preprint

View full text Add to dashboard Cite

show abstract

Heritable intraspecific variation among prey in size and movement interact to shape predation risk and potential natural selection

Coblentz,

Yang,

Dalal

et al. 2024

Functional Ecology

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Predator and prey traits are important determinants of the outcomes of trophic interactions. In turn, the outcomes of trophic interactions shape predator and prey trait evolution. How species' traits respond to selection from trophic interactions depends crucially on whether and how heritable species' traits are and their genetic correlations. Of the many traits influencing the outcomes of trophic interactions, body size and movement traits have emerged as key traits. Yet, how these traits shape and are shaped by trophic interactions is unclear, as few studies have simultaneously measured the impacts of these traits on the outcomes of trophic interactions, their heritability, and their correlations within the same system. We used outcrossed lines of the ciliate protist Paramecium caudatum from natural populations to examine variation in morphology and movement behaviour, the heritability of that variation, and its effects on Paramecium susceptibility to predation by the copepod Macrocyclops albidus. We found that the Paramecium lines exhibited heritable variation in body size and movement traits. In contrast to expectations from allometric relationships, body size and movement speed showed little covariance among clonal lines. The proportion of Paramecium consumed by copepods was positively associated with Paramecium body size and velocity but with an interaction such that greater velocities led to greater predation risk for large body‐sized paramecia but did not alter predation risk for smaller paramecia. The proportion of paramecia consumed was not related to copepod body size. These patterns of predation risk and heritable trait variation in paramecia suggest that copepod predation may act as a selective force operating independently on movement and body size and generating the strongest selection against large, high‐velocity paramecia. Our results illustrate how ecology and genetics can shape potential natural selection on prey traits through the outcomes of trophic interactions. Further simultaneous measures of predation outcomes, traits, and their quantitative genetics will provide insights into the evolutionary ecology of species interactions and their eco‐evolutionary consequences. Read the free Plain Language Summary for this article on the Journal blog.

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My Paramecium Study, Retrospect and Prospect

Cited by 2 publications

References 27 publications

Heritable intraspecific variation among prey in size and movement interact to shape predation risk and potential natural selection

Heritable intraspecific variation among prey in size and movement interact to shape predation risk and potential natural selection

Heritable intraspecific variation among prey in size and movement interact to shape predation risk and potential natural selection

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