Aging in sexual and obligately asexual clones of Daphnia from temporary ponds

Dudycha, Jeffry L.; Hassel, Christiane

doi:10.1093/plankt/fbt008

Cited by 26 publications

(23 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…More generally, and whatever the genetic architecture for variation in lifespan may be (AP or MA), a fundamental question is to find an evolutionary interpretation of differences in lifespan or ageing patterns among populations and species. So far, most research has focused on differences in selection pressures among populations or among species as a potential evolutionary source for such differences, including work on Daphnia (Dudycha , ; Dudycha and Hassel ). The results of our study, however, strongly support a prominent role of genetic drift and thus nonadaptive processes in explaining this variation, at least at the within‐species level.…”

Section: Discussionmentioning

confidence: 99%

Reduced Lifespan and Increased Ageing Driven by Genetic Drift in Small Populations

2014

View full text Add to dashboard Cite

Explaining the strong variation in lifespan among organisms remains a major challenge in evolutionary biology. Whereas previous work has concentrated mainly on differences in selection regimes and selection pressures, we hypothesize that differences in genetic drift may explain some of this variation. We develop a model to formalize this idea and show that the strong positive relationship between lifespan and genetic diversity predicted by this model indeed exists among populations of Daphnia magna, and that ageing is accelerated in small populations. Additional results suggest that this is due to increased drift in small populations rather than adaptation to environments favoring faster life histories. First, the correlation between genetic diversity and lifespan remains significant after statistical correction for potential environmental covariates. Second, no trade-offs are observed; rather, all investigated traits show clear signs of increased genetic load in the small populations. Third, hybrid vigor with respect to lifespan is observed in crosses between small but not between large populations. Together, these results suggest that the evolution of lifespan and ageing can be strongly affected by genetic drift, especially in small populations, and that variation in lifespan and ageing may often be nonadaptive, due to a strong contribution from mutation accumulation. K E Y W O R D S :Daphnia, genetic drift, mutation accumulation, population size, senescence.

show abstract

Section: Discussionmentioning

confidence: 99%

Reduced Lifespan and Increased Ageing Driven by Genetic Drift in Small Populations

2014

View full text Add to dashboard Cite

show abstract

“…The allocation of energy to repair and maintenance of the organism subtracts from energy available for growth and reproduction, and energy allocation is therefore subject to natural selection (Kirkwood 1990, Abrams 1993. Theory predicts that high senescence rates may evolve when extrinsic mortality is age dependent and high relative to total mortality, and if the population is under density-dependent regulation (Abrams 1993, Ricklefs 2008, Baudisch and Vaupel 2010, Fabian and Flatt 2011, and there is both experimental (Stearns et al 2000) and observational evidence for such a relation (Dudycha 2003, Robert and Bronikowski 2010, Dudycha and Hassel 2013, Tozzini et al 2013. Theory predicts that high senescence rates may evolve when extrinsic mortality is age dependent and high relative to total mortality, and if the population is under density-dependent regulation (Abrams 1993, Ricklefs 2008, Baudisch and Vaupel 2010, Fabian and Flatt 2011, and there is both experimental (Stearns et al 2000) and observational evidence for such a relation (Dudycha 2003, Robert and Bronikowski 2010, Dudycha and Hassel 2013, Tozzini et al 2013.…”

Section: Introductionmentioning

confidence: 99%

Interrelations between senescence, life‐history traits, and behavior in planktonic copepods

Kiørboe

Ceballos

Thygesen

2015

Ecology

View full text Add to dashboard Cite

The optimal allocation of resources to repair vs. reproduction in an organism may depend on the magnitude and pattern of the external mortality it is experiencing, which, in turn, may depend on its feeding and mate-finding behavior. Thus, the fundamental activities of an organism, i.e., to feed, to survive, and to reproduce, are interrelated through trade-offs. Here, we use small planktonic copepods to examine how adult longevity and ageing patterns in a protected laboratory environment relate to the feeding mode (active searching vs. passive ambush feeding), mate-finding behavior, and spawning mode of the species. We show that average adult longevity varies between species by an order of magnitude and is independent of body size. Ambush feeders that carry their eggs have longer average life spans and experience higher mortality later in life relative to active feeders that broadcast their eggs. Males generally have shorter life spans and experience higher mortality earlier in life than females, and this difference may be accentuated in species where dangerous mate-finding is male biased. We finally show a trade-off between longevity and fecundity, with ambush feeders producing eggs at a rate five to 10 times lower than the active feeders, consistent with predictions from optimal resource allocation theory.

show abstract

“…Daphnia from temporary ponds were observed to experience higher rates of mortality than those from permanent lakes [13]. Concomitant with this, Daphnia from temporary ponds exhibited shorter lifespans and faster juvenile growth compared to those from permanent lakes [14]. In Drosophila melanogaster , a decrease in longevity and earlier peak fecundity can be directly selected for by increasing extrinsic mortality levels [15].…”

Section: Introductionmentioning

confidence: 99%

Effects of Extrinsic Mortality on the Evolution of Aging: A Stochastic Modeling Approach

Shokhirev

Johnson

2014

PLoS ONE

View full text Add to dashboard Cite

The evolutionary theories of aging are useful for gaining insights into the complex mechanisms underlying senescence. Classical theories argue that high levels of extrinsic mortality should select for the evolution of shorter lifespans and earlier peak fertility. Non-classical theories, in contrast, posit that an increase in extrinsic mortality could select for the evolution of longer lifespans. Although numerous studies support the classical paradigm, recent data challenge classical predictions, finding that high extrinsic mortality can select for the evolution of longer lifespans. To further elucidate the role of extrinsic mortality in the evolution of aging, we implemented a stochastic, agent-based, computational model. We used a simulated annealing optimization approach to predict which model parameters predispose populations to evolve longer or shorter lifespans in response to increased levels of predation. We report that longer lifespans evolved in the presence of rising predation if the cost of mating is relatively high and if energy is available in excess. Conversely, we found that dramatically shorter lifespans evolved when mating costs were relatively low and food was relatively scarce. We also analyzed the effects of increased predation on various parameters related to density dependence and energy allocation. Longer and shorter lifespans were accompanied by increased and decreased investments of energy into somatic maintenance, respectively. Similarly, earlier and later maturation ages were accompanied by increased and decreased energetic investments into early fecundity, respectively. Higher predation significantly decreased the total population size, enlarged the shared resource pool, and redistributed energy reserves for mature individuals. These results both corroborate and refine classical predictions, demonstrating a population-level trade-off between longevity and fecundity and identifying conditions that produce both classical and non-classical lifespan effects.

show abstract

Aging in sexual and obligately asexual clones of Daphnia from temporary ponds

Cited by 26 publications

References 30 publications

Reduced Lifespan and Increased Ageing Driven by Genetic Drift in Small Populations

Reduced Lifespan and Increased Ageing Driven by Genetic Drift in Small Populations

Interrelations between senescence, life‐history traits, and behavior in planktonic copepods

Effects of Extrinsic Mortality on the Evolution of Aging: A Stochastic Modeling Approach

Contact Info

Product

Resources

About