scholarly journals Sex-specific patterns of senescence in artificial insect populations varying in sex-ratio to manipulate reproductive effort

2019 ◽  
Author(s):  
Charly Jehan ◽  
Manon Chogne ◽  
Thierry Rigaud ◽  
Yannick Moret
Keyword(s):  
Sex Ratio ◽  
Reproductive Effort ◽  
Male Reproduction ◽  
Sexually Dimorphic ◽  
Single Experiment ◽  
Sexual Competition ◽  
Trade Off ◽  
Trade Offs ◽  
Mealworm Beetle ◽  
Ratio Condition

Abstract Background The disposable soma theory of ageing assumes that organisms optimally trade-off limited resources between reproduction and longevity to maximize fitness. Early reproduction should especially trade-off against late reproduction and longevity because of reduced investment into somatic protection, including immunity. Moreover, as optimal reproductive strategies of males and females differ, sexually dimorphic patterns of senescence may evolve. In particular, as males gain fitness through mating success, sexual competition should be a major factor accelerating male senescence. In a single experiment, we examined these possibilities by establishing artificial populations of the mealworm beetle, Tenebrio molitor , in which we manipulated the sex-ratio to generate variable levels of investment into reproductive effort and sexual competition in males and females.Results As predicted, variation in sex-ratio affected male and female reproductive efforts, with contrasted sex-specific trade-offs between lifetime reproduction, survival and immunity. High effort of reproduction accelerated mortality in females, without affecting immunity, but high early reproductive success was observed only in balanced sex-ratio condition. Male reproduction was costly on longevity and immunity, mainly because of their investment into copulations rather than in sexual competition.Conclusions Our results suggest that T. molitor males, like females, maximize fitness through enhanced longevity, partly explaining their comparable longevity.

scholarly journals Sex-specific patterns of senescence in artificial insect populations varying in sex-ratio to manipulate reproductive effort

2020 ◽  
Author(s):  
Charly Jehan ◽  
Manon Chogne ◽  
Thierry Rigaud ◽  
Yannick Moret
Keyword(s):  
Sex Ratio ◽  
Reproductive Effort ◽  
Male Reproduction ◽  
Single Experiment ◽  
Sexual Competition ◽  
Trade Off ◽  
Trade Offs ◽  
Mealworm Beetle ◽  
Ratio Condition ◽  
Males And Females

Abstract Background: The disposable soma theory of ageing assumes that organisms optimally trade-off limited resources between reproduction and longevity to maximize fitness. Early reproduction should especially trade-off against late reproduction and longevity because of reduced investment into somatic protection, including immunity. Moreover, as optimal reproductive strategies of males and females differ, sexually dimorphic patterns of senescence may evolve. In particular, as males gain fitness through mating success, sexual competition should be a major factor accelerating male senescence. In a single experiment, we examined these possibilities by establishing artificial populations of the mealworm beetle, Tenebrio molitor, in which we manipulated the sex-ratio to generate variable levels of investment into reproductive effort and sexual competition in males and females. Results: As predicted, variation in sex-ratio affected male and female reproductive efforts, with contrasted sex-specific trade-offs between lifetime reproduction, survival and immunity. High effort of reproduction accelerated mortality in females, without affecting immunity, but high early reproductive success was observed only in balanced sex-ratio condition. Male reproduction was costly on longevity and immunity, mainly because of their investment into copulations rather than in sexual competition. Conclusions: Our results suggest that T. molitor males, like females, maximize fitness through enhanced longevity, partly explaining their comparable longevity.

scholarly journals Sex-specific patterns of senescence in artificial insect populations varying in sex-ratio to manipulate reproductive effort

2020 ◽  
Author(s):  
Charly Jehan ◽  
Manon Chogne ◽  
Thierry Rigaud ◽  
Yannick Moret
Keyword(s):  
Sex Ratio ◽  
Reproductive Effort ◽  
Male Reproduction ◽  
Single Experiment ◽  
Sexual Competition ◽  
Trade Off ◽  
Trade Offs ◽  
Mealworm Beetle ◽  
Ratio Condition ◽  
Males And Females

Abstract Background: The disposable soma theory of ageing assumes that organisms optimally trade-off limited resources between reproduction and longevity to maximize fitness. Early reproduction should especially trade-off against late reproduction and longevity because of reduced investment into somatic protection, including immunity. Moreover, as optimal reproductive strategies of males and females differ, sexually dimorphic patterns of senescence may evolve. In particular, as males gain fitness through mating success, sexual competition should be a major factor accelerating male senescence. In a single experiment, we examined these possibilities by establishing artificial populations of the mealworm beetle, Tenebrio molitor, in which we manipulated the sex-ratio to generate variable levels of investment into reproductive effort and sexual competition in males and females. Results: As predicted, variation in sex-ratio affected male and female reproductive efforts, with contrasted sex-specific trade-offs between lifetime reproduction, survival and immunity. High effort of reproduction accelerated mortality in females, without affecting immunity, but high early reproductive success was observed only in balanced sex-ratio condition. Male reproduction was costly on longevity and immunity, mainly because of their investment into copulations rather than in sexual competition. Conclusions: Our results suggest that T. molitor males, like females, maximize fitness through enhanced longevity, partly explaining their comparable longevity.

Muscles or testes? Comparative evidence for sexual competition among dioecious blood parasites (Schistosomatidae) of vertebrates

Parasitology ◽  
2000 ◽  
Vol 120 (1) ◽  
pp. 45-56 ◽  
Author(s):  
S. MORAND ◽  
C. D. M. MÜLLER-GRAF
Keyword(s):  
Sex Ratio ◽  
Phylogenetic Analyses ◽  
Cladistic Analysis ◽  
Blood Parasites ◽  
Sexual Competition ◽  
Trade Off ◽  
The Family ◽  
Biased Sex Ratio ◽  
Molecular Information ◽  
Plesiomorphic Character

Schistosomes, which live as parasitic adults in the blood vessels of mammals, birds and crocodiles, are unique among trematodes because they have separate sexes. Several studies have shown that the sex ratio is often biased towards males. Sexual dimorphism can be very important in several genera (Schistosoma, Heterobilharzia, Schistosomatium), as larger males grip smaller females in a gynecophoric canal. But not all schistomatid species have developed a gynecophoric canal. It is also striking that the number of testes varies widely, from a small number of testes reported (2–7) to a very high number (>500). We tested the hypothesis of trade-off investment by males: muscle (as estimated by the length of the gynecophoric canal) in order to sequester one or a few females, or testes in order to inseminate numerous females. We used recent comparative methods, which need phylogenetic information of the analysed species. We employed a morphological cladistic analysis of the Schistosomatidae and a construction of a phylogenetic supertree of Schistosoma based on available molecular information. Our phylogenetic analysis supports previous hypotheses on the origin and diversification of the schistosomes. The family seems to have originated as parasites of crocodiles (or possibly other related poikilotherms) and to have secondarily evolved within the Aves and then mammals. Our phylogenetic analyses show that (1) the possession of a gynecophoric canal is a plesiomorphic character, and several reductions of this character have occurred during the diversification of the Schistosomatidae; (2) a small number of testes is a plesiomorphic stage, and an increase of testes number has occurred several times. Finally, our comparative analysis suggests that there is a trade-off between investment in muscle or in number of testes (other variables being controlled for). Male competition for access to females seems to follow two ways: investment in testes in order to fertilize a high number of females or investment in muscle in order to hold and sequester one (Schistosoma) or a few females (Heterobilharzia). We show the existence of the trade-off between muscles and testes in connection with a male biased sex ratio. The development of dioecy cannot explain the trade-off between muscles and testes, which instead appears to be a result of sexual selection possibly driven by the male biased sex ratio.

The trade-off of reproduction and survival in slow-breeding seabirds

2010 ◽  
Vol 88 (9) ◽  
pp. 889-899 ◽  
Author(s):  
F. Stephen Dobson ◽  
Pierre Jouventin
Keyword(s):  
Life History ◽  
Body Size ◽  
Life History Traits ◽  
Feeding Rate ◽  
Reproductive Effort ◽  
Original Data ◽  
Age At Maturity ◽  
Trade Off ◽  
Trade Offs ◽  
Regression Techniques

A trade-off between reproduction and survival is one of the most consistent empirical aspects of life-history diversification. One explanation for this interspecific pattern is evolved differences in the balance of allocation to reproduction versus individual maintenance and survival. The same pattern is expected, however, simply as a result of differences among species in body size. We tested these alternatives using original data from 44 species of albatrosses and petrels, long-lived seabirds that breed very slowly. After application of regression techniques to remove the effects of body size and phylogeny, annual reproduction and survival exhibited a significant trade-off. Our measures of reproductive effort also exhibited significant trade-offs with age at maturity, the latter strongly associated with survival. Feeding rate of chicks, success at fledging chicks, and annual chick production were also significantly associated. In conclusion, after removing the effects of body size, we found a significant trade-off of reproduction and survival, in spite of the fact that these long-lived birds lay only one egg at a time. Our examination of the pattern among life-history traits of these slow breeders and their pelagic feeding ecology provide support for the evolutionary explanation of a trade-off of reproduction and survival.

Sexual differences and sex ratios of dioecious plants under stressful environments

2021 ◽  
Author(s):  
Miao Liu ◽  
Helena Korpelainen ◽  
Chunyang Li
Keyword(s):  
Sexual Dimorphism ◽  
Sex Ratio ◽  
Plant Species ◽  
Environmental Gradients ◽  
Environmental Stressors ◽  
Sexual Differences ◽  
Sex Characteristics ◽  
Sexually Dimorphic ◽  
Dioecious Plants ◽  
Trade Offs

Abstract Dioecious plants exhibit sexual dimorphism in both sexual features (reproductive organs) and secondary sex characteristics (vegetative traits). Sexual differences in secondary traits, including morphological, physiological and ecological characters, have been commonly associated with trade-offs between the cost of reproduction and other plant functions. Such trade-offs may be modified by environmental stressors, although there is evidence that sexually dimorphic responses to stress do not always exist in all plant species. When sexual dimorphism exists, sexually different responses appear to depend on the species and stress types. Yet, further studies on dioecious plant species are needed to allow the generalization of stress effects on males and females. Additionally, sexual dimorphism may influence the frequency and distribution of the sexes along environmental gradients, likely causing niche differentiation and spatial segregation of sexes. At the present, the causes and mechanisms governing sex ratio biases are poorly understood. This review aims to discuss sex-specific responses and sex ratio biases occurring under adverse conditions, which will advance our knowledge of sexually dimorphic responses to environmental stressors.

scholarly journals Reproductive effort affects subsequent horn growth in sexually dimorphic male ungulates

2021 ◽  
Author(s):  
Christian Simon Willisch ◽  
Peter Neuhaus
Keyword(s):  
Reproductive Effort ◽  
Evolutionary Ecology ◽  
Energy Allocation ◽  
Sexually Dimorphic ◽  
Capra Ibex ◽  
Secondary Sexual Characters ◽  
Horn Growth ◽  
Trade Offs ◽  
The Relationship ◽  
Secondary Sexual

AbstractTrade-offs between reproductive effort and subsequent growth in males are not well explored, despite their relevance in questions of individual energy allocation. Regarding the growth of sexual secondary characters in polygynous breeding male mammals, indeed, no conclusive studies exist. We investigated in male Alpine ibex (Capra ibex) the relationship between their behavioral reproductive effort, current horn size, and subsequent horn growth. While controlling for age, no evidence was found for male behavioral reproductive effort during the rut being affected by their horn size. On the other hand, reproductive effort significantly decreased age-specific horn growth during the following summer. Our study provides evidence that growth of secondary sexual characters is traded against behavioral investments in reproduction in a male mammal. It bears important implications for the understanding of energy allocation between various life-history components and the evolutionary ecology of secondary sexual characters.

Dual Goals for Speed and Accuracy on the Same Performance Task

2012 ◽  
Vol 11 (3) ◽  
pp. 118-126 ◽  
Author(s):  
Olive Emil Wetter ◽  
Jürgen Wegge ◽  
Klaus Jonas ◽  
Klaus-Helmut Schmidt
Keyword(s):  
Memory Scanning ◽  
Performance Task ◽  
Performance Tasks ◽  
Trade Off ◽  
Test Experiment ◽  
Trade Offs ◽  
New Finding ◽  
Sternberg Paradigm ◽  
Speed Accuracy ◽  
Speed And Accuracy

In most work contexts, several performance goals coexist, and conflicts between them and trade-offs can occur. Our paper is the first to contrast a dual goal for speed and accuracy with a single goal for speed on the same task. The Sternberg paradigm (Experiment 1, n = 57) and the d2 test (Experiment 2, n = 19) were used as performance tasks. Speed measures and errors revealed in both experiments that dual as well as single goals increase performance by enhancing memory scanning. However, the single speed goal triggered a speed-accuracy trade-off, favoring speed over accuracy, whereas this was not the case with the dual goal. In difficult trials, dual goals slowed down scanning processes again so that errors could be prevented. This new finding is particularly relevant for security domains, where both aspects have to be managed simultaneously.

The Effects of Decision Time on Perceptions of Decisions and Decision Makers in (Moral) Trade-Off Scenarios

2019 ◽  
Author(s):  
Anna Katharina Spälti ◽  
Mark John Brandt ◽  
Marcel Zeelenberg
Keyword(s):  
Decision Process ◽  
Decision Time ◽  
Decision Makers ◽  
Process Information ◽  
Total N ◽  
Trade Off ◽  
Financial Gain ◽  
Trade Offs ◽  
Sacred Values ◽  
Moral Context

People often have to make trade-offs. We study three types of trade-offs: 1) "secular trade-offs" where no moral or sacred values are at stake, 2) "taboo trade-offs" where sacred values are pitted against financial gain, and 3) "tragic trade-offs" where sacred values are pitted against other sacred values. Previous research (Critcher et al., 2011; Tetlock et al., 2000) demonstrated that tragic and taboo trade-offs are not only evaluated by their outcomes, but are also evaluated based on the time it took to make the choice. We investigate two outstanding questions: 1) whether the effect of decision time differs for evaluations of decisions compared to decision makers and 2) whether moral contexts are unique in their ability to influence character evaluations through decision process information. In two experiments (total N = 1434) we find that decision time affects character evaluations, but not evaluations of the decision itself. There were no significant differences between tragic trade-offs and secular trade-offs, suggesting that the decisions structure may be more important in evaluations than moral context. Additionally, the magnitude of the effect of decision time shows us that decision time, may be of less practical use than expected. We thus urge, to take a closer examination of the processes underlying decision time and its perception.

Predicting Undesired Treatment Outcome in Mental Healthcare: Machine Learning Study (Preprint)

2019 ◽  
Author(s):  
Kasper Van Mens ◽  
Joran Lokkerbol ◽  
Richard Janssen ◽  
Robert de Lange ◽  
Bea Tiemens
Keyword(s):  
Machine Learning ◽  
Treatment Outcome ◽  
Mental Health Treatment ◽  
Mental Healthcare ◽  
Machine Learning Algorithms ◽  
Gradient Boosting ◽  
Trade Off ◽  
Trade Offs ◽  
Outcome Monitoring ◽  
Extreme Gradient Boosting

BACKGROUND It remains a challenge to predict which treatment will work for which patient in mental healthcare. OBJECTIVE In this study we compare machine algorithms to predict during treatment which patients will not benefit from brief mental health treatment and present trade-offs that must be considered before an algorithm can be used in clinical practice. METHODS Using an anonymized dataset containing routine outcome monitoring data from a mental healthcare organization in the Netherlands (n = 2,655), we applied three machine learning algorithms to predict treatment outcome. The algorithms were internally validated with cross-validation on a training sample (n = 1,860) and externally validated on an unseen test sample (n = 795). RESULTS The performance of the three algorithms did not significantly differ on the test set. With a default classification cut-off at 0.5 predicted probability, the extreme gradient boosting algorithm showed the highest positive predictive value (ppv) of 0.71(0.61 – 0.77) with a sensitivity of 0.35 (0.29 – 0.41) and area under the curve of 0.78. A trade-off can be made between ppv and sensitivity by choosing different cut-off probabilities. With a cut-off at 0.63, the ppv increased to 0.87 and the sensitivity dropped to 0.17. With a cut-off of at 0.38, the ppv decreased to 0.61 and the sensitivity increased to 0.57. CONCLUSIONS Machine learning can be used to predict treatment outcomes based on routine monitoring data.This allows practitioners to choose their own trade-off between being selective and more certain versus inclusive and less certain.

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