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Measurement of Survival Time in Brachionus Rotifers: Synchronization of Maternal Conditions
Published on: July 22, 2016
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Non-genetic polymorphisms in rotifers: environmental and endogenous controls, development, and features for
1Department of Biological Sciences, Dartmouth College, Hanover, NH, 03755, USA.
Biological Reviews of the Cambridge Philosophical Society
|March 23, 2016
Summary
Rotifer polyphenisms, or non-genetic variations, are reviewed. These polyphenisms are categorized by their environmental adaptability, with some suited for stable conditions and others for unpredictable environments, acting as bet-hedging strategies.
Area of Science:
- Evolutionary Biology
- Developmental Biology
- Rotifer Biology
Background:
- Monogonont rotifers exhibit significant non-genetic polymorphisms (polyphenisms), particularly in spine length and female morphology.
- These polyphenisms arise during oogenesis or embryological development from diploid eggs within the maternal body cavity.
- Species like Brachionids and Asplanchna display diverse morphs, including variations in size, shape, and spine length.
Purpose of the Study:
- To review and compare rotifer polyphenisms based on key features of morph determination.
- To categorize these polyphenisms based on their adaptive strategies for different environmental conditions.
- To analyze the ecological significance of polyphenisms as adaptations for survival and reproduction.
Main Methods:
- Comparative review of existing literature on rotifer polyphenisms.
- Analysis of polyphenisms based on criteria: type of variation, inducing signal, response universality, fitness cost, reversibility, and ecological significance.
- Categorization of polyphenisms into two major types based on environmental predictability.
Main Results:
- Polyphenisms are classified into two main categories: those suited for predictable environments and those for unpredictable environments (bet-hedging).
- Transitions for predictable environments involve universal responses to environmental signals, continuous variation, low cost, and rapid reversibility.
- Transitions for unpredictable environments involve partial responses, discontinuous variation, diapause, high cost, and slow reversibility.
Conclusions:
- Rotifer polyphenisms represent diverse adaptive strategies for environmental variability.
- Morphological and physiological variations serve as crucial adaptations for defense, feeding, and survival under fluctuating conditions.
- Simultaneous production of different morphs, as seen in Brachionus calyciflorus and Asplanchna spp., suggests adaptations for uncertain futures.
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