scholarly journals Density-dependent morphological plasticity and trade-offs among vegetative traits in Eichhornia crassipes (Pontederiaceae)

2013 ◽  
Vol 43 (4) ◽  
pp. 455-459 ◽  
Author(s):  
Eleonora Alvarenga Andrade ◽  
Mário Eduardo Avelar Barbosa ◽  
Guilherme Ramos Demetrio
Keyword(s):  
Resource Allocation ◽  
Life History ◽  
Eichhornia Crassipes ◽  
Environmental Changes ◽  
Morphological Plasticity ◽  
High Density ◽  
Allocation Pattern ◽  
Density Dependent ◽  
Trade Offs ◽  
Vegetative Traits

Density-dependent responses are an important component of the organism life-history, and the resource allocation theory is a central concept to the life-history theory. When resource allocation varies due to environmental changes, a plant may change its morphology or physiology to cope with the new conditions, a process known as phenotypic plasticity. Our study aimed to evaluate how plant density affects Eichhornia crassipes allocation patterns. A total of 214 individuals in high and low density were collected. The density effect was observed in all plant traits examined including biomass accumulation. All traits of E. crassipes demonstrated higher values in high density conditions, except for biomass of leaves. Density exhibited a high influence on vegetative traits of E. crassipes, but did not influence allocation pattern, since a trade-off among the vegetative traits was not found. The morphological plasticity and the absence of trade-offs were discussed as strategies to overcome neighbor plants in competition situations. In high density conditions, there were clear changes in the morphology of the plants which probably allows for their survival in a highly competitive environment.

scholarly journals Foundress Number, But Not Queen Size or Boldness, Predicts Colony Life-History in Wild Paper Wasps

2019 ◽  
Author(s):  
Colin M. Wright ◽  
David N. Fisher ◽  
Wayne V. Nerone ◽  
James L.L. Lichtenstein ◽  
Elizabeth A. Tibbetts ◽  
...  
Keyword(s):  
Resource Allocation ◽  
Life History ◽  
Body Size ◽  
Life Histories ◽  
Life History Traits ◽  
Positive Association ◽  
Paper Wasps ◽  
Trade Offs ◽  
Behavioral Tendencies ◽  
Queen Size

AbstractColonies of social insects exhibit a spectacular variety of life histories. Here we documented the degree of variation in colony life-history traits, mostly related to productivity, in two species of wild paper wasps. We then tested for associations between colony life-history traits to look for trade-offs or positively associated syndromes, and examined whether individual differences in the behavioral tendencies of foundresses (Polistes metricus) or the number of cofoundresses (P. fuscatus) influenced colony life-history. The majority of our measures of colony life-history were positively related, indicating no obvious resource allocation trade-offs. Instead, the positive association of traits into a productivity syndrome appears to be driven by differences in queen or microhabitat quality. Syndrome structure differed only marginally between species. Queen boldness and body size were not associated with colony life-history inP. metricus. Colonies initiated by multipleP. fuscatusfoundresses were generally more productive, and this advantage was approximately proportional to the number of cofoundresses. These findings demonstrate that colony life-history traits can be associated together much like individual life-history traits, and the associations seen here convey that differences in overall productivity drive between-colony differences in life-history.

scholarly journals Telomeres positively correlate with pace-of-life and elongate with age in a wild mammal

2021 ◽  
Author(s):  
Mathilde Tissier ◽  
Patrick Bergeron ◽  
Dany Garant ◽  
Sandrine Zahn ◽  
Francois Criscuolo ◽  
...  
Keyword(s):  
Resource Allocation ◽  
Life History ◽  
Life Histories ◽  
Life History Strategies ◽  
Trade Off ◽  
Pace Of Life ◽  
Trade Offs ◽  
Proactive Behaviour ◽  
Anti Cancer ◽  
Fast Pace

Understanding ageing and the diversity of life histories is a cornerstone in biology. Telomeres, the protecting caps of chromosomes, are thought to be involved in ageing, cancer risks and to modulate life-history strategies. They shorten with cell division and age in somatic tissues of most species, possibly limiting lifespan. The resource allocation trade-off hypothesis predicts that short telomeres have thus co-evolved with early reproduction, proactive behaviour and reduced lifespan, i.e. a fast Pace-of-Life Syndrome (POLS). Conversely, since short telomeres may also reduce the risks of cancer, the anti-cancer hypothesis advances that they should be associated with slow POLS. Conclusion on which hypothesis best supports the role of telomeres as mediators of life-history strategies is hampered by a lack of study on wild short-lived vertebrates, apart from birds. Using seven years of data on wild Eastern chipmunks Tamias striatus, we highlighted that telomeres elongate with age and do not limit lifespan in this species. Furthermore, short telomeres correlated with a slow POLS in a sex-specific way. Females with short telomeres had a delayed age at first breeding and a lower fecundity rate than females with long telomeres, whereas those differences were not recorded in males. Our findings support most predictions adapted from the anti-cancer hypothesis, but none of those made under the resource allocation trade-off hypothesis. Results are in line with an increasing body of evidence suggesting that resource allocation trade-offs alone cannot explaining the diversity of telomere length in adult somatic cells and life-histories observed across the tree of life.

scholarly journals Density-dependent natural selection and trade-offs in life history traits

Science ◽  
1991 ◽  
Vol 253 (5018) ◽  
pp. 433-435 ◽  
Author(s):  
L. Mueller ◽  
P. Guo ◽  
F. Ayala
Keyword(s):  
Life History ◽  
Natural Selection ◽  
Life History Traits ◽  
Density Dependent ◽  
Trade Offs

scholarly journals Experimental evolution of parasite life-history traits in Strongyloides ratti (Nematoda)

2007 ◽  
Vol 274 (1617) ◽  
pp. 1467-1474 ◽  
Author(s):  
Steve Paterson ◽  
Rebecca Barber
Keyword(s):  
Life History ◽  
Experimental Evolution ◽  
Life History Traits ◽  
Evolutionary Ecology ◽  
Response To Selection ◽  
Trade Off ◽  
Density Dependent ◽  
Conspecific Density ◽  
Trade Offs ◽  
General Prediction

Evolutionary ecology predicts that parasite life-history traits, including a parasite's survivorship and fecundity within a host, will evolve in response to selection and that their evolution will be constrained by trade-offs between traits. Here, we test these predictions using a nematode parasite of rats, Strongyloides ratti , as a model. We performed a selection experiment by passage of parasite progeny from either early in an infection (‘fast’ lines) or late in an infection (‘slow’ lines). We found that parasite fecundity responded to selection but that parasite survivorship did not. We found a trade-off mediated via conspecific density-dependent constraints; namely, that fast lines exhibit higher density-independent fecundity than slow lines, but fast lines suffered greater reduction in fecundity in the presence of density-dependent constraints than slow lines. We also found that slow lines both stimulate a higher level of IgG1, which is a marker for a Th2-type immune response, and show less of a reduction in fecundity in response to IgG1 levels than for fast lines. Our results confirm the general prediction that parasite life-history traits can evolve in response to selection and indicate that such evolutionary responses may have significant implications for the epidemiology of infectious disease.

scholarly journals Co-occurrence of contrasting life-history strategies in a metapopulation inhabiting temporally variable and stable breeding sites

2018 ◽  
Author(s):  
Hugo Cayuela ◽  
Sam Cruickshank ◽  
Hannelore Brandt ◽  
Arpat Ozgul ◽  
Benedikt Schmidt
Keyword(s):  
Resource Allocation ◽  
Life History ◽  
Life History Theory ◽  
Life History Evolution ◽  
Environmental Stochasticity ◽  
Life History Strategies ◽  
Slowing Down ◽  
Trade Offs ◽  
Temporal Variance ◽  
History Evolution

Life-history theory states that, during the lifetime of an individual, resources are allocated to either somatic maintenance or reproduction. Resource allocation trade-offs determine the evolution and ecology of life-history strategies and determine an organism position along the fast-slow continuum. Theory predicts that environmental stochasticity is an important driver of resource allocation and therefore life-history evolution. Highly stochastic environments are expected to increase uncertainty in reproductive success and select for iteroparity and a slowing down of the life history. To date, most empirical studies have used comparisons among species to examine these theoretical predictions. By contrast, few have investigated how environmental stochasticity affects life-history strategies at the intraspecific level. In this study, we examined how variation in breeding site stochasticity (among-year variability in pond volume and hydroperiod) promotes the co-occurrence of different life-history strategies in a spatially structured population, and determines life-history position along the fast-slow continuum in the yellow-bellied toad (Bombina variegata). We collected mark-recapture data from a metapopulation and used multievent capture-recapture models to estimate survival, recruitment and breeding probabilities. We found higher survival and longer lifespans in populations inhabiting variable sites compared to those breeding in stable ones. In addition, probabilities of recruitment and skipping a breeding event were higher in variable sites. The temporal variance of survival and recruitment probabilities as well as the probability to skip breeding was higher in variable sites. Taken together, these findings indicate that populations breeding in variable sites experienced a slowing down of the life-history. Our study thus revealed similarities in the macroevolutionary and microevolutionary processes shaping life-history evolution.

Experimentally increased costs of parental care are shunted to offspring in species with extended care

2019 ◽  
Author(s):  
Gretchen F. Wagner ◽  
Emeline Mourocq ◽  
Michael Griesser
Keyword(s):  
Life History ◽  
Parental Care ◽  
Total Duration ◽  
Bird Species ◽  
Life History Strategy ◽  
Experimental Treatment ◽  
Cost Of Care ◽  
Adult Survival ◽  
Supporting Evidence ◽  
Trade Offs

Biparental care systems are a valuable model to examine conflict, cooperation, and coordination between unrelated individuals, as the product of the interactions between the parents influences the fitness of both individuals. A common experimental technique for testing coordinated responses to changes in the costs of parental care is to temporarily handicap one parent, inducing a higher cost of providing care. However, dissimilarity in experimental designs of these studies has hindered interspecific comparisons of the patterns of cost distribution between parents and offspring. Here we apply a comparative experimental approach by handicapping a parent at nests of five bird species using the same experimental treatment. In some species, a decrease in care by a handicapped parent was compensated by its partner, while in others the increased costs of care were shunted to the offspring. Parental responses to an increased cost of care primarily depended on the total duration of care that offspring require. However, life history pace (i.e., adult survival and fecundity) did not influence parental decisions when faced with a higher cost of caring. Our study highlights that a greater attention to intergenerational trade-offs is warranted, particularly in species with a large burden of parental care. Moreover, we demonstrate that parental care decisions may be weighed more against physiological workload constraints than against future prospects of reproduction, supporting evidence that avian species may devote comparable amounts of energy into survival, regardless of life history strategy.

The intrinsic mechanism of life history trade-offs: The mediating role of control striving

2017 ◽  
Vol 49 (6) ◽  
pp. 783 ◽  
Author(s):  
Yan WANG ◽  
Zhenchao LIN ◽  
Bowen HOU ◽  
Shijin SUN
Keyword(s):  
Life History ◽  
Mediating Role ◽  
Trade Offs ◽  
Intrinsic Mechanism ◽  
Control Striving

Biosecurity and Public Health Ethics Issues Raised by Biological Threats

2019 ◽  
pp. 773-785
Author(s):  
Nicholas Evans ◽  
Thomas Inglesby
Keyword(s):  
Public Health ◽  
Resource Allocation ◽  
Infectious Diseases ◽  
Ethical Issues ◽  
Emerging Infectious Diseases ◽  
Biological Weapon ◽  
Ethical Values ◽  
Dual Use ◽  
Health Concerns ◽  
Trade Offs

This chapter introduces ethical issues that arise in the context of biosecurity: policies and actions intended to prevent the development or emergence, or mitigate the consequences, of serious biological threats. These threats could include deliberate biological weapon attacks (bioterrorism), pandemics, emerging infectious diseases, or major laboratory accidents. The basic values that underpin these public health concerns are first introduced. Ethical issues that arise before, during, and following a biosecurity crisis are then examined, including issues of resource allocation, dual-use research, and the possibility of quarantine. Their resolution requires trade-offs among different ethical values, including utility, fairness, and liberty.

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