scholarly journals Effects of resource availability on the trade-off between seed and vegetative reproduction

2010 ◽  
Vol 3 (4) ◽  
pp. 251-258 ◽  
Author(s):  
L. Fu ◽  
S. Wang ◽  
Z. Liu ◽  
I. Nijs ◽  
K. Ma ◽  
...  
Keyword(s):  
Resource Availability ◽  
Vegetative Reproduction ◽  
Trade Off

Cost of seed versus rhizome production in Agropyron repens

1991 ◽  
Vol 69 (12) ◽  
pp. 2678-2683 ◽  
Author(s):  
E. G. Reekie
Keyword(s):  
Seed Production ◽  
Resource Availability ◽  
Nitrogen Availability ◽  
Vegetative Reproduction ◽  
Light Availability ◽  
Trade Off ◽  
Production Allocation ◽  
Trade Offs ◽  
Allocation Patterns ◽  
Agropyron Repens

I examined growth and allocation patterns in genotypes of Agropyron repens isolated from six habitats that differed in disturbance frequency. The trade-off between seed and rhizome production and between either mode of propagation and growth of leaves, stems, and roots was determined by calculating both within- and among-genotype correlations between functions. I also examined how level of light and nitrogen availability affected these trade-offs. Large differences were found among populations in how resources were divided between infructescences and rhizomes, but there was no evidence of a direct trade-off. Regardless of environment, or level at which correlations were examined, there was never a negative correlation between seed and rhizome production. Depending on level of nitrogen and light availability, there was usually a trade-off between seed or rhizome production and growth of leaves, stems, and roots. The two modes of propagation differed in how they responded to resource availability such that their relative cost varied among environments. I suggest differences among populations in allocation to seed versus rhizome production are due to these differences in cost. When cost of seed production is high relative to rhizome production, allocation to rhizome is favored. Conversely, when cost of rhizome production is high relative to seed production, allocation to infructescences is favored. Key words: vegetative reproduction, sexual reproduction, allocation, disturbance, reproductive cost, resource availability, clonal growth.

scholarly journals A trade-off between having many sons and shorter maternal post-reproductive survival in pre-industrial Finland

2013 ◽  
Vol 9 (2) ◽  
pp. 20130034 ◽  
Author(s):  
Samuli Helle ◽  
Virpi Lummaa
Keyword(s):  
Resource Availability ◽  
Demographic Data ◽  
Direct Costs ◽  
Reproductive Costs ◽  
Costs Of Reproduction ◽  
Access To Resources ◽  
Trade Off ◽  
High Resource

A bias in reproduction towards sons, which are energetically more costly than daughters, has been suggested to shorten parental lifespan, but previous results have been mixed. Reproductive costs should be most evident in low rather than high resource settings, and are not expected to be severe in men, because women pay higher direct costs of reproduction. We, therefore, used demographic data from pre-industrial Finland to investigate whether the number of sons and daughters born affected their parents’ post-reproductive survival and whether this was related to parent's resource availability. Irrespective of access to resources, mothers, but not fathers, with many sons suffered from reduced post-reproductive survival, and this association decreased as mothers aged. Our results provide evidence that Finnish mothers traded long post-reproductive lifespan for giving birth to many sons.

scholarly journals Model of Construction Subcontractors Selection with Time Windows for their Availability

2019 ◽  
Vol 65 (4) ◽  
pp. 295-307
Author(s):  
S. Biruk ◽  
P. Jaskowski ◽  
M. Krzemiński
Keyword(s):  
Mathematical Model ◽  
Resource Availability ◽  
Construction Projects ◽  
Programming Model ◽  
Time Windows ◽  
Mixed Integer ◽  
Time Cost ◽  
Trade Off ◽  
Availability Constraints ◽  
The Cost

AbstractMost construction projects involve subcontracting some work packages. A subcontractor is employed on the basis of their bid as well as according to their availability. A viable schedule must account for resource availability constraints. These resources (e.g. crews, subcontractors) engage in many projects, so they become at the disposal for a new project only in certain periods. One of the key tasks of a planner is thus synchronizing the work of resources between concurrent projects. The paper presents a mathematical model of the problem of selecting subcontractors or general contractor’s crews for a time-constrained project that accounts for the availability of contractors, as well as for the cost of subcontracting works. The proposed mixed integer-binary linear programming model enables the user to perform the time/cost trade-off analysis.

scholarly journals To group or not to group: Effect of prolonged exposure to predation and resource availability on the shoaling behaviour of zebrafish (Danio rerio)

2020 ◽  
Author(s):  
Nawaf Abdul Majeed ◽  
Vivek Philip Cyriac ◽  
Ullasa Kodandaramaiah
Keyword(s):  
Danio Rerio ◽  
Resource Availability ◽  
Environmental Conditions ◽  
Prolonged Exposure ◽  
Group Structure ◽  
Food Resource ◽  
Group Living ◽  
Predation Pressure ◽  
Trade Off ◽  
Shoaling Behaviour

AbstractIndividuals of many species live in groups to obtain anti-predatory advantages, foraging benefits and for social reasons. Living in large groups can reduce predation, but as group size increases, competition for resources also increases. The trade-off between the advantages of group living for an individual and competition caused by it can determine group dynamics, and this trade-off can vary with environmental conditions. Shoaling behaviour, the tendency of fish to form groups, is shown to be affected by factors such as resource availability, presence of predators and conspecifics. Although studies indicate that both predation and starvation pressure in an environment can determine whether fish choose to shoal or not, whether prolonged exposure to such conditions influences shoaling behaviour remains little explored. Here, we test how predation pressure and resource availability may interactively shape the shoaling behaviour of zebrafish (Danio rerio) when exposed to combinations of these pressures over a two-week period. We find that shoal size increases with predation and decreases with starvation, and that greater predation pressure increases shoaling tendencies even under reduced food availability. Overall, we show that prolonged exposure to varying predation pressure and resource availability can together influence shoaling tendencies of fish even when such pressures are relaxed.Significant statementIn group living species, group structure and dynamics depend on various intrinsic factors and environmental stressors. Shoaling behaviour in fish, where individuals aggregate to form groups, is shown to be altered with environmental factors such as predation and resource availability. Although studies have examined the effects of these cues on shoaling behaviour, the ecological circumstances experienced by fish could also influence shoaling tendencies. We here show that shoaling behaviour is also shaped by previous experience of fish to predation and food resource availability. We check how shoaling behaviour varies with differences in predation pressure and resource availability after prolonged exposure to these conditions by measuring the shoal size and shoal cohesion in zebrafish. This study illuminates how shoaling tendencies of individuals shaped by the environmental conditions persist even when these environmental pressures are removed.

Relationships between size, biomass allocation, reproduction, and survival in Triglochin palustris: implications for the effects of goose herbivory

1998 ◽  
Vol 76 (12) ◽  
pp. 2164-2176 ◽  
Author(s):  
Christa PH Mulder ◽  
R W Ruess
Keyword(s):  
Biomass Allocation ◽  
Vegetative Reproduction ◽  
Population Level ◽  
Plant Size ◽  
Flowering Plants ◽  
Parent Plant ◽  
Trade Off ◽  
Plant Parts ◽  
Vegetative Plant ◽  
Increased Risk

Triglochin palustris (arrowgrass) on the Yukon-Kuskokwim Delta reproduces primarily vegetatively, and is heavily grazed by geese. To link effects of herbivory on individuals to population-level effects, we examined relationships between plant size or biomass allocation and survival or reproduction by matching more than 400 individuals into groups and sequentially harvesting individuals from each group. We compared size and biomass allocation for nonreproductive plants and plants with either or both modes of reproduction in exclosed plots, and examined effects of clipping leaves or inflorescences in flowering and nonflowering plants. Survival and vegetative reproduction increased with plant size, particularly bulb size, but was unrelated to biomass allocation. Very small plants do not reproduce, very large plants produce both flowers and stolons, and intermediate sized plants produce either flowers or stolons. Inflorescences require greater biomass investment than stolons, resulting in decreased allocation to all vegetative plant parts except roots. Plants that produce flowers seldom regenerate overwintering bulbs on the parent plant, indicating a trade-off with survival. Geese may decrease flowering by reducing plant size and consuming inflorescences. Flowering plants have much higher rates of herbivory than other plants, suggesting that increased risk of herbivory results in low rates of flowering.Key words: Alaska, brant geese, sexual reproduction, subarctic salt marsh, vegetative reproduction.

A Flow-Preserving Algorithm for the Time-Cost Trade-Off Problem

1982 ◽  
Vol 14 (2) ◽  
pp. 109-113 ◽  
Author(s):  
Suleyman Tufekci
Keyword(s):  
Time Cost ◽  
Trade Off
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