نتایج جستجو برای: reproductive allocation
تعداد نتایج: 175223 فیلتر نتایج به سال:
Chemical defense is assumed to be costly and therefore algae should allocate defense investments in a way to reduce costs and optimize their overall Wtness. Thus, lifetime expectation of particular tissues and their contribution to the Wtness of the alga may aVect defense allocation. Two brown algae common to the SE PaciWc coasts, Lessonia nigrescens Bory and Macrocystis integrifolia Bory, feat...
Reproduction is essential in studying of aging and senescence in fruit flies as for the resources devoted to egg-laying are subtracted from the total resources of the organism and thus intensive reproduction shorten the life span of an individual. According to prevailing opinion, the stochastic nature of spatial and temporal distribution of external factors leads to randomness of reproductive p...
Here we investigate the allocation of resources between growth and reproduction by surveying the dynamics of natural populations of the aquatic detritivorous mudsnail Potamopyrgus antipodarum from two interconnected lakes that differ in trophic state. The size distributions and reproductive output of the snail populations was analyzed monthly by field surveys spanning 3 years, and in a controll...
The Disability Adjusted Life-Year (DALY) heralded a new age in the development of an evidence base for priority setting and resource allocation. The DALY was intended to represent sound measurement of the incidence and prevalence of conditions in a process by which burden of disease would be determined, health conditions prioritised and interventions evaluated. However, in the reification of ob...
Organisms allocate resources to reproduction in response to the costs and benefits of current and future reproductive opportunities. According to the differential allocation hypothesis, females allocate more resources to high-quality males. We tested whether a fish species lacking parental care (zebrafish, Danio rerio) expresses male size-dependent differential allocation in monogamous spawning...
Sex allocation theory predicts that mothers should adjust their sex-specific reproductive investment in relation to the predicted fitness returns from sons versus daughters. Sex allocation theory has proved to be successful in some invertebrate taxa but data on vertebrates often fail to show the predicted shift in sex ratio or sex-specific resource investment. This is likely to be partly explai...
Besides conspicuous changes in behaviour, manipulative parasites may also induce subtle physiological effects in the host that may also be favourable to the parasite. In particular, parasites may be able to influence the re-allocation of resources in their own favour. We studied the association between the presence of the acanthocephalan parasite, Pomphorhynchus laevis, and inter-individual var...
Life-history theory suggests that iteroparous plants should be flexible in their allocation of resources toward growth and reproduction. Such plasticity could have consequences for herbivores that prefer or specialize on vegetative versus reproductive structures. To test this prediction, we studied the response of the cactus bug (Narnia pallidicornis) to meristem allocation by tree cholla cactu...
Here I study a kin selection model of reproductive effort, the allocation of resources to fecundity versus survival, in a patch-structured population. Breeding females remain in the same patch for life. Offspring have costly, partial long-distance dispersal and compete for breeding sites, which become vacant upon the death of previous occupants. The main result is that the evolutionarily stable...
The trade-off between allocation to sexual and clonal reproduction in clonal plants is influenced by a variety of environmental factors; however, it has rarely been examined under field conditions. In this study, we investigated the trade-off between two modes of reproduction in Carex brevicuspis C. B. Clarke across a small-scale elevational gradient (21-27 m a.s.l.) at the Dongting Lake wetlan...
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