Trade-offs in resource allocation that favour resprouting affect the competitive ability of woody seedlings in grassy communities

2009 ◽  
Vol 97 (6) ◽  
pp. 1374-1382 ◽  
Author(s):  
Peter J. Clarke ◽  
Kirsten J. E. Knox
Author(s):  
Nicholas Evans ◽  
Thomas Inglesby

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.


AoB Plants ◽  
2019 ◽  
Author(s):  
Miranda D Redmond ◽  
Thomas Seth Davis ◽  
Scott M Ferrenberg ◽  
Andreas P Wion

Abstract The cost of plant reproduction or defense at the expense of other fitness traits is a central component of life history theory. Yet the three central resource allocation pathways of growth, reproduction, and defense have rarely been assessed simultaneously nor across individual to landscape scales. This information is critical towards identifying the physiological, environmental, and genetic mechanisms underpinning resource allocation. This study assessed trade-offs in resource allocation between tree growth, defense, and reproduction across scales among piñon pine (Pinusedulis), a widespread mast-seeding conifer of the southwestern USA. Time series (2004-2016) of tree growth (radial and primary shoot growth), defense (resin duct production; a key constitutive defense for this species), and cone production among individual trees from populations across a broad environmental gradient were used to investigate these trade-offs in resource allocation across three scales: individual, population, and landscape. We found evidence for a defense-reproduction trade-off among individuals whereby total resin duct area in annual xylem rings was lower during years of above average cone production. Despite variability in cone and resin duct production across trees within a population and across populations, there was no association between these fitness traits at either of those scales. There was no evidence of trade-offs between cone production and growth at any scales measured, whereas resin duct production and growth were positively related at all scales. Our study suggests that a strategic trade-off occurs whereby investment into defense is temporarily curtailed to favor reproduction, despite increased risk of exposure to natural enemies and the ability of piñon pine to simultaneously allocate carbon to growth and defense. Our study provides new insights into physiological expressions of growth, defense, and reproduction over time in this long-lived masting conifer and indicates the presence of trade-offs with direct importance for individual fitness and population dynamics under global change.


2017 ◽  
Vol 114 (31) ◽  
pp. E6457-E6465 ◽  
Author(s):  
Alexandra-M. Reimers ◽  
Henning Knoop ◽  
Alexander Bockmayr ◽  
Ralf Steuer

Cyanobacteria are an integral part of Earth’s biogeochemical cycles and a promising resource for the synthesis of renewable bioproducts from atmospheric CO2. Growth and metabolism of cyanobacteria are inherently tied to the diurnal rhythm of light availability. As yet, however, insight into the stoichiometric and energetic constraints of cyanobacterial diurnal growth is limited. Here, we develop a computational framework to investigate the optimal allocation of cellular resources during diurnal phototrophic growth using a genome-scale metabolic reconstruction of the cyanobacterium Synechococcus elongatus PCC 7942. We formulate phototrophic growth as an autocatalytic process and solve the resulting time-dependent resource allocation problem using constraint-based analysis. Based on a narrow and well-defined set of parameters, our approach results in an ab initio prediction of growth properties over a full diurnal cycle. The computational model allows us to study the optimality of metabolite partitioning during diurnal growth. The cyclic pattern of glycogen accumulation, an emergent property of the model, has timing characteristics that are in qualitative agreement with experimental findings. The approach presented here provides insight into the time-dependent resource allocation problem of phototrophic diurnal growth and may serve as a general framework to assess the optimality of metabolic strategies that evolved in phototrophic organisms under diurnal conditions.


2016 ◽  
Vol 103 (10) ◽  
pp. 1838-1846 ◽  
Author(s):  
Marta R. Pereira ◽  
Cristian S. Dambros ◽  
Charles E. Zartman

2019 ◽  
Author(s):  
Colin M. Wright ◽  
David N. Fisher ◽  
Wayne V. Nerone ◽  
James L.L. Lichtenstein ◽  
Elizabeth A. Tibbetts ◽  
...  

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.


2019 ◽  
Author(s):  
Joey R. Bernhardt ◽  
Pavel Kratina ◽  
Aaron Pereira ◽  
Manu Tamminen ◽  
Mridul K. Thomas ◽  
...  

AbstractCompetition for limiting resources is among the most fundamental ecological interactions and has long been considered a key driver of species coexistence and biodiversity. Species’ minimum resource requirements, their R*s, are key traits that link individual physiological demands to the outcome of competition. However, a major question remains unanswered - to what extent are species’ competitive traits able to evolve in response to resource limitation? To address this knowledge gap, we performed an evolution experiment in which we exposed Chlamydomonas reinhardtii for approximately 285 generations to seven environments in chemostats which differed in resource supply ratios (including nitrogen, phosphorus and light limitation) and salt stress. We then grew the ancestors and descendants in common garden and quantified their competitive abilities for essential resources. We investigated constraints on trait evolution by testing whether changes in resource requirements for different resources were correlated. Competitive abilities for phosphorus improved in all populations, while competitive abilities for nitrogen and light increased in some populations and decreased in others. In contrast to the common assumption that there are trade-offs between competitive abilities for different resources, we found that improvements in competitive ability for a resource came at no detectable cost. Instead, improvements in competitive ability for multiple resources were either positively correlated or not significantly correlated. Using resource competition theory, we then demonstrated that rapid adaptation in competitive traits altered the predicted outcomes of competition. These results highlight the need to incorporate contemporary evolutionary change into predictions of competitive community dynamics over environmental gradients.


2018 ◽  
Author(s):  
Wolfram Liebermeister

AbstractCells need to make an efficient use of metabolites, proteins, energy, membrane space, and time, and resource allocation is also an important aspect of metabolism. How, for example, should cells distribute their protein budget between different cellular functions, e.g. different metabolic pathways, to maximise growth? Cellular resource allocation can be studied by combining biochemical network models with optimality problems that choose metabolic states by their cost and benefit. Various types of resource allocation problems have been proposed. The underlying mechanistic models may describe different cellular systems (e.g. metabolic pathways, networks, or compromises between metabolism and protein production) on different level of detail and using different mathematical formulations (e.g. stoichiometric or kinetic). The optimality problems may use metabolite levels, enzyme levels, or fluxes as variables, assume different cost or benefit functions, and describe different kinds of trade-offs, in which cell variables are either constrained or treated as optimisation objectives. Due to all these differences, optimality problems may be hard to compare or combine. To bring them under one umbrella, I show that they can be derived from a common framework, and that their optimality conditions all show the same mathematical form. This unified view on metabolic optimality problems can be used to justify and combine various modelling approaches and biochemical optimality problems.


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