scholarly journals Actuarial senescence in a long-lived orchid challenges our current understanding of ageing

2016 ◽  
Vol 283 (1842) ◽  
pp. 20161217 ◽  
Author(s):  
Johan Petter Dahlgren ◽  
Fernando Colchero ◽  
Owen R. Jones ◽  
Dag-Inge Øien ◽  
Asbjørn Moen ◽  
...  
Keyword(s):  
Death Rate ◽  
Trajectory Analysis ◽  
Reproductive Investment ◽  
Growing Season ◽  
Weibull Model ◽  
Plant Population Dynamics ◽  
Trade Off ◽  
Climatic Regions ◽  
Germ Cell Line ◽  
Positive Effect

The dominant evolutionary theory of actuarial senescence—an increase in death rate with advancing age—is based on the concept of a germ cell line that is separated from the somatic cells early in life. However, such a separation is not clear in all organisms. This has been suggested to explain the paucity of evidence for actuarial senescence in plants. We used a 32 year study of Dactylorhiza lapponica that replaces its organs each growing season, to test whether individuals of this tuberous orchid senesce. We performed a Bayesian survival trajectory analysis accounting for reproductive investment, for individuals under two types of land use, in two climatic regions. The mortality trajectory was best approximated by a Weibull model, showing clear actuarial senescence. Rates of senescence in this model declined with advancing age, but were slightly higher in mown plots and in the more benign climatic region. At older ages, senescence was evident only when accounting for a positive effect of reproductive investment on mortality. Our results demonstrate actuarial senescence as well as a survival–reproduction trade-off in plants, and indicate that environmental context may influence senescence rates. This knowledge is crucial for understanding the evolution of demographic senescence and for models of plant population dynamics.

scholarly journals Glucocorticoids, state-dependent reproductive investment and success in the face of danger in a long-lived bird

2020 ◽  
Author(s):  
Kristina Noreikienė ◽  
Kim Jaatinen ◽  
Benjamin B. Steele ◽  
Markus Öst
Keyword(s):  
Predation Risk ◽  
Telomere Length ◽  
Clutch Size ◽  
Body Condition ◽  
Nest Predation ◽  
Hatching Success ◽  
Reproductive Investment ◽  
Trade Off ◽  
Relative Telomere Length ◽  
Future Reproduction

AbstractGlucocorticoid hormones may mediate trade-offs between current and future reproduction. However, understanding their role is complicated by predation risk, which simultaneously affects the value of the current reproductive investment and elevates glucocorticoid levels. Here, we shed light on these issues in long-lived female Eiders (Somateria mollissima) by investigating how current reproductive investment (clutch size) and hatching success relate to faecal glucocorticoid metabolite [fGCM] level and residual reproductive value (minimum years of breeding experience, body condition, relative telomere length) under spatially variable predation risk. Our results showed a positive relationship between colony-specific predation risk and mean colony-specific fGCM levels. Clutch size and female fGCM were negatively correlated only under high nest predation and in females in good body condition, previously shown to have a longer life expectancy. We also found that younger females with longer telomeres had smaller clutches. The drop in hatching success with increasing fGCM levels was least pronounced under high nest predation risk, suggesting that elevated fGCM levels may allow females to ensure some reproductive success under such conditions. Hatching success was positively associated with female body condition, with relative telomere length, particularly in younger females, and with female minimum age, particularly under low predation risk, showing the utility of these metrics as indicators of individual quality. In line with a trade-off between current and future reproduction, our results show that high potential for future breeding prospects and increased predation risk shift the balance toward investment in future reproduction, with glucocorticoids playing a role in the resolution of this trade-off.

scholarly journals Enzymatic antioxidants but not baseline glucocorticoids mediate the reproduction–survival trade-off in a wild bird

2018 ◽  
Vol 285 (1892) ◽  
pp. 20182141 ◽  
Author(s):  
Stefania Casagrande ◽  
Michaela Hau
Keyword(s):  
Life History ◽  
Body Condition ◽  
Redox State ◽  
Reproductive Investment ◽  
Redox System ◽  
Reactive Oxygen Metabolites ◽  
Enzymatic Antioxidants ◽  
Trade Off ◽  
Trade Offs ◽  
Nest Provisioning

The trade-off between reproductive investment and survival is central to life-history theory, but the relative importance and the complex interactions among the physiological mechanisms mediating it are still debated. Here we experimentally tested whether baseline glucocorticoid hormones, the redox system or their interaction mediate reproductive investment–survival trade-offs in wild great tits ( Parus major ). We increased the workload of parental males by clipping three feathers on each wing, and 5 days later determined effects on baseline corticosterone concentrations (Cort), redox state (reactive oxygen metabolites, protein carbonyls, glutathione peroxidase [GPx], total non-enzymatic antioxidants), body mass, body condition, reproductive success and survival. Feather-clipping did not affect fledgling numbers, chick body condition, nest provisioning rates or survival compared with controls. However, feather-clipped males lost mass and increased both Cort and GPx concentrations. Within feather-clipped individuals, GPx increases were positively associated with reproductive investment (i.e. male nest provisioning). Furthermore, within all individuals, males that increased GPx suffered reduced survival rates. Baseline Cort increases were related to mass loss but not to redox state, nest provisioning or male survival. Our findings provide experimental evidence that changes in the redox system are associated with the trade-off between reproductive investment and survival, while baseline Cort may support this trade-off indirectly through a link with body condition. These results also emphasize that plastic changes in individuals, rather than static levels of physiological signals, may mediate life-history trade-offs.

Literature review on effect of microfinance institutions on poverty in South Asian countries and their sustainability

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Prashant Kumar Gupta ◽  
Seema Sharma
Keyword(s):  
Literature Review ◽  
South Asian ◽  
Systematic Literature Review ◽  
Future Research ◽  
Microfinance Institutions ◽  
Asian Countries ◽  
Exclusion Criteria ◽  
Trade Off ◽  
Content Type ◽  
Positive Effect

PurposeThe authors present a systematic literature review on microfinance institutions’ (MFIs) effect on poverty and how they can ensure their sustainability. The purpose of this article is to review the effect of MFIs on poverty in South Asian countries. The analysis and review of the selected corpus of literature also provide avenues for future research.Design/methodology/approachA total of 95 papers from 49 journals in 4 academic libraries and publishers were systematically studied and classified. The authors define the keywords and the inclusion/exclusion criteria for the identification of papers. The review includes an analysis of the selected papers that give insights about publications with respect to themes, number of themes covered in individual publications, nations, scope, methodology, number of methods used and publication trend.FindingsThe literature indicates the positive effect of microfinance on poverty but with a varying degree on various categories of poor. The relation between poverty and microfinance is, however, dependent on the nation under the scanner. While sustainability and outreach co-exist, their trade-off is still a matter of debate.Originality/valueThis is the first systematic literature review on MFIs’ effect on poverty in South Asian nations. Additionally, the authors discuss the literature on the trade-off between sustainability and outreach for MFIs.

scholarly journals Surviving Andersonville: The Benefits of Social Networks in POW Camps

2007 ◽  
Vol 97 (4) ◽  
pp. 1467-1487 ◽  
Author(s):  
Dora L Costa ◽  
Matthew E Kahn
Keyword(s):  
Social Networks ◽  
Death Rate ◽  
Union Army ◽  
Significant Positive Effect ◽  
Survival Probabilities ◽  
In Captivity ◽  
The Impact ◽  
Positive Effect

Twenty-seven percent of the Union Army prisoners captured July 1863 or later died in captivity. At Andersonville, the death rate may have been as high as 40 percent. How did men survive such horrific conditions? Using two independent datasets, we find that friends had a statistically significant positive effect on survival probabilities and that the closer the ties between friends as measured by such identifiers as ethnicity, kinship, and the same hometown, the bigger was the impact of friends on survival probabilities. (JEL N41, Z13)

Stubble management effects on canola performance across different climatic regions of western Canada

2015 ◽  
Vol 95 (1) ◽  
pp. 149-159 ◽  
Author(s):  
Michael J. Cardillo ◽  
Paul Bullock ◽  
Rob Gulden ◽  
Aaron Glenn ◽  
Herb Cutforth
Keyword(s):  
Snow Water Equivalent ◽  
Growing Season ◽  
Moisture Stress ◽  
Climatic Conditions ◽  
Western Canada ◽  
Spring Precipitation ◽  
Canadian Prairies ◽  
Climatic Regions ◽  
Snow Water ◽  
Management Effects

Cardillo, M. J., Bullock, P., Gulden, R., Glenn, A. and Cutforth, H. 2015. Stubble management effects on canola performance across different climatic regions of western Canada. Can. J. Plant Sci. 95: 149–159. Previous research in the most arid region of the Canadian prairies has shown that wheat stubble cut tall the previous year can improve performance of the following canola crop. This study aimed to determine if tall stubble could benefit canola across the climatic conditions typically experienced in western Canada. Tall stubble impacts on canola were monitored over 11 site-years located throughout the prairies. At each site, tall stubble (50 cm) was compared with short stubble (20 cm). At some sites the stubble lodged allowing an unintended comparison between stubble that remained intact and stubble that was flattened. The comparison of snow water equivalent showed tall stubble caught more snow than short stubble but the benefit of additional spring soil moisture was masked by heavy spring precipitation in both 2011 and 2012. Canola biomass and yield were significantly lower in damaged versus intact stubble, either short or tall. In both years, wet spring conditions were followed by hotter and drier weather in the mid to late growing season. Soil under the damaged stubble (short or tall) likely warmed and dried more slowly in the spring, limiting early-season growth, biomass and yield. At sites where both tall and short stubble remained intact, there was a significant yield advantage with tall stubble. The intact tall stubble may have slowed evaporation and soil drying compared with intact short stubble, which reduced moisture stress later in the growing season, imparting a yield advantage.

scholarly journals Features of growing chickpea in the foothill zone of the Kabardino-Balkarian Republic

2020 ◽  
Vol 222 ◽  
pp. 02008
Author(s):  
Zalina Tarasheva ◽  
Irina Khanieva ◽  
Aliy Boziev ◽  
Takhir Chapaev ◽  
Andemirkan Odizhev
Keyword(s):  
Growth Regulators ◽  
Growing Season ◽  
Nitrogen Fixing ◽  
Nitrogen Fixing Bacteria ◽  
Potassium Sodium ◽  
Sodium Humate ◽  
Field Germination ◽  
Golden Jubilee ◽  
Positive Effect

In the foothill zone of the Kabardino-Balkarian Republic in 2013-2015, studies were carried out in order to study the effect of growth regulators and rhizotorfin on the formation of elements of the structure of the chickpea crop. The objects of research were the varieties of chickpeas “Golden Jubilee” and “Privo 1”. The background for testing biological preparations was pre-sowing inoculation of seeds with rhizotorphin based on nitrogen-fixing bacteria and their treatment with microelements (P120K60MoV). The following drugs were used: Albit, Alfastim, Potassium / sodium humate with microelements. The use of growth regulators and rhizotorfin has a positive effect on field germination, the duration of the growing season and the yield of chickpea. The analysis of the data in our studies showed that the cultivation of the chickpea variety “Golden Jubilee” in the foothill zone of the Kabardino-Balkarian Republic is more profitable.

scholarly journals Сomparative evaluation of the effect of the bacterial biopreparation phytop 8.67–8 and the bacterial-humic complex agrofit-humate-b (bcg “afg-b”) on the growth and development of kiwano varieties green dragon

2021 ◽  
pp. 67-76
Author(s):  
A. V. Pastukhova ◽  
I. Е. Lavrishchev ◽  
A. F. Petrov ◽  
V. Р. Tsvetkova ◽  
V. S. Maslenikova
Keyword(s):  
Chemical Composition ◽  
Growth And Development ◽  
Growing Season ◽  
Fertilizer Application ◽  
Mineral Fertilizers ◽  
Yield And Quality ◽  
Novosibirsk Region ◽  
Positive Effect

The results of studying the influence of various biological and mineral fertilizers: Phytop 8.67, Agrofit-humate-B (BKG «AFG-B”) – on the growth and development of plants, as well as the yield and quality of kiwano fruits of the Green Dragon variety are presented. During the study, phenological and morphological observations, accounting and evaluation of the quality of the obtained fruits, analysis of the chemical composition of the fruits were carried out. The obtained data confirmed the positive effect of the use of biological preparations on the structure and quality of the resulting crop of kiwano, which will allow us to recommend this crop for cultivation in the territory of the Novosibirsk region, using experimentally proven methods and norms of fertilizer application during the growing season of plants.

scholarly journals Fungicides against diseases of lawn grass leaves

2019 ◽  
pp. 7-9
Author(s):  
S. Retman ◽  
O. Nychyporuk ◽  
О. Shevchuk
Keyword(s):  
Powdery Mildew ◽  
Technical Efficiency ◽  
Disease Severity ◽  
Growing Season ◽  
Disease Spread ◽  
Septoria Leaf Blotch ◽  
Leaf Blotch ◽  
Chemical Groups ◽  
Positive Effect

Goal. To evaluate the effectiveness of the use of fungicides of various chemical groups against the leaf diseases turfgrass. Methods. The research was carried out in 2015—2017 on the lawn mixture «Universal» in the zone of the Polissya of Ukraine. The effect of fungicides of various chemical groups was investigated (Impact T, SC; Bumper Super, EC; Amistar Extra 280 SC, SC; Alto Super 300 EC, EC; Maxim 025 FS, FS; Horus 75 WG, WG). Fungicides were applied twice. The first spraying was carried out when development of diseases in control plot reached 3—5%, the second — in 30 days. The assessments were performed according to generally accepted methods, disease spread, disease severity and technical efficiency of pesticides were determined. Results. During the period of research, the most common leaf diseases of turfgrass, which eveloped annually and had a significant severity during the growing season, were powdery mildew and septoria leaf blotch. After two-time spraying, the technical efficiency of fungicides against powdery mildew reached 82.2—92.2%, against septoria leaf blotch up to 80.2%. The most effective against powdery mildew was the use of Alto Super 330 EC, EC (0.5 l / ha), Amistar Extra 280 SC, SC (0.75 l / ha) and tank mixture of Maxim 025 FS, FS (0.75 l / ha and 1.0 l / ha) with Horus 75 WG, VH (0.6 kg / ha). Against the septoria leaf blotch, the highest efficiency was shown by Alto Super 330 EC, EC (0.5 l / ha), Bumper Super, EC (0.8 l / ha) and Maxim 025 FS, FS (1.0 l / ha) + Horus 75 WG, WG (0.6 kg / ha). In addition, due to the reduction of disease severity, a positive effect of fungicides on the quality of the lawn was achieved and the projective coating increased to 92—93%. Conclusion. The use of fungicides contributes to the reduction of disease and the formation of quality herbs. The best indicators against flour dew and septoriosis of leaves were obtained for the treatment of Alto Super 330 EC, CE (0.5 l / ha) and tank Maxim 025 FS, tc.s. (1.0 l / ha) + Horus 75 WG, VH (0.6 kg / ha).

scholarly journals What should a poor mother do? Influence of host plant quality on oviposition strategy and behavior in a polyphagous moth

2021 ◽  
Author(s):  
Kristina Karlsson Green ◽  
Benjamin Houot ◽  
Peter Anderson
Keyword(s):  
Host Plant ◽  
Plant Species ◽  
Reproductive Investment ◽  
Egg Laying ◽  
Plant Quality ◽  
Host Plant Quality ◽  
Egg Weight ◽  
Trade Off ◽  
Host Plant Species ◽  
Larval Host

To maximise fitness, individuals may apply different reproductive strategies. Such strategies could be phenotypically plastic and vary depending on the environment. For example, when resources are limited females often face a trade-off between investing in offspring quantity and quality, and how she balances this trade-off may depend on the environment. For phytophagous insects, and especially generalist insects, variation in host plant quality could have large effects on mating, reproduction and offspring performance. Here, we study if the polyphagous moth Spodoptera littoralis, which selects host plants through experience-based preference induction, also has a flexible allocation between egg weight and egg number as well as in temporal egg-laying behavior depending on larval host plant species. We found that S. littoralis has a canalized egg size and that an increased reproductive investment is made in egg quantity rather than egg quality. This increased investment depends on larval host plant species, probably reflecting parental condition. The constant egg weight may be due to physiological limitations or to limited possibilities to increase fitness through larger offspring size. We furthermore found that differences in onset of egg-laying is mainly due to differences in mating propensity between individuals raised on different host plant species. Thus, females do not seem to make a strategic reproductive investment in challenging environments. Instead, the low-quality host plant induces less and later reproduction, which could have consequences for population dynamics in the field.

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