scholarly journals Breeding seasonality generates reproductive trade-offs in a long-lived mammal

2021 ◽  
Author(s):  
Jules Dezeure ◽  
Alice Baniel ◽  
Alecia J. Carter ◽  
Guy Cowlishaw ◽  
Bernard Godelle ◽  
...  
Keyword(s):  
Optimal Timing ◽  
Birth Timing ◽  
Offspring Survival ◽  
Fitness Components ◽  
Reproductive Seasonality ◽  
Trade Off ◽  
Seasonal Environment ◽  
Trade Offs ◽  
Fitness Consequences ◽  
Future Reproduction

ABSTRACTThe evolutionary benefits of reproductive seasonality are usually measured by a single fitness component, namely offspring survival to nutritional independence (Bronson, 2009). Yet different fitness components may be maximised by dissimilar birth timings. This may generate fitness trade-offs that could be critical to understanding variation in reproductive timing across individuals, populations and species. Here, we use long-term demographic and behavioural data from wild chacma baboons (Papio ursinus) living in a seasonal environment to test the adaptive significance of seasonal variation in birth frequencies. Like humans, baboons are eclectic omnivores, give birth every 1-3 years to a single offspring that develops slowly, and typically breed year-round. We identify two distinct optimal birth timings in the annual cycle, located 4-months apart, which maximize offspring survival or minimize maternal interbirth intervals (IBIs), by respectively matching the annual food peak with late or early weaning. Observed births are the most frequent between these optima, supporting an adaptive trade-off between current and future reproduction. Furthermore, infants born closer to the optimal timing favouring maternal IBIs (instead of offspring survival) throw more tantrums, a typical manifestation of mother-offspring conflict (Maestripieri, 2002). Maternal trade-offs over birth timing, which extend into mother-offspring conflict after birth, may commonly occur in long-lived species where development from birth to independence spans multiple seasons. Such trade-offs may substantially weaken the benefits of seasonal reproduction, and our findings therefore open new avenues to understanding the evolution of breeding phenology in long-lived animals, including humans.SIGNIFICANCE STATEMENTWhy some species breed seasonally and others do not remain unclear. The fitness consequences of birth timing have traditionally been measured on offspring survival, ignoring other fitness components. We investigated the effects of birth timing on two fitness components in wild baboons, who breed year-round despite living in a seasonal savannah. Birth timing generates a trade-off between offspring survival and future maternal reproductive pace, meaning that mothers cannot maximize both. When birth timing favours maternal reproductive pace (instead of offspring survival), behavioural manifestations of mother-offspring conflict around weaning are intense. These results open new avenues to understand the evolution of reproductive timings in long-lived animals including humans, where such reproductive trade-offs may commonly weaken the intensity of reproductive seasonality.

scholarly journals Birth timing generates reproductive trade-offs in a non-seasonal breeding primate

2021 ◽  
Vol 288 (1950) ◽  
Author(s):  
Jules Dezeure ◽  
Alice Baniel ◽  
Alecia Carter ◽  
Guy Cowlishaw ◽  
Bernard Godelle ◽  
...  
Keyword(s):  
Optimal Timing ◽  
Birth Timing ◽  
Offspring Survival ◽  
Early Weaning ◽  
Reproductive Seasonality ◽  
Papio Ursinus ◽  
Seasonal Environment ◽  
Trade Offs ◽  
Future Reproduction

The evolutionary benefits of reproductive seasonality are often measured by a single-fitness component, namely offspring survival. Yet different fitness components may be maximized by different birth timings. This may generate fitness trade-offs that could be critical to understanding variation in reproductive timing across individuals, populations and species. Here, we use long-term demographic and behavioural data from wild chacma baboons ( Papio ursinus ) living in a seasonal environment to test the adaptive significance of seasonal variation in birth frequencies. We identify two distinct optimal birth timings in the annual cycle, located four-month apart, which maximize offspring survival or minimize maternal interbirth intervals (IBIs), by respectively matching the annual food peak with late or early weaning. Observed births are the most frequent between these optima, supporting an adaptive trade-off between current and future reproduction. Furthermore, infants born closer to the optimal timing favouring maternal IBIs (instead of offspring survival) throw more tantrums, a typical manifestation of mother–offspring conflict. Maternal trade-offs over birth timing, which extend into mother–offspring conflict after birth, may commonly occur in long-lived species where development from birth to independence spans multiple seasons. Our findings therefore open new avenues to understanding the evolution of breeding phenology in long-lived animals, including humans.

Are nest defense behaviours and fitness components linked in white-rumped swallows (Tachycineta leucorrhoa)?

Behaviour ◽  
2019 ◽  
Vol 156 (2) ◽  
pp. 181-201
Author(s):  
Uschi Wischhoff ◽  
Fernando Marques-Santos ◽  
Giselle Bonetti ◽  
Lilian T. Manica ◽  
James J. Roper ◽  
...  
Keyword(s):  
Wild Animal ◽  
Nest Defence ◽  
Costs And Benefits ◽  
Fitness Components ◽  
Trade Off ◽  
Trade Offs ◽  
Animal Populations ◽  
Behavioural Types ◽  
One Year ◽  
Different Levels

Abstract How are personalities maintained in wild animal populations? A possible mechanism is the existence of trade-offs between fitness components (survival and reproductive success) among behavioural types. We investigated this trade-off in white-rumped swallows (Tachycineta leucorrhoa) by capturing adults and monitoring their reproduction over time. We focused on the personality trait of nest defence against a human. We found that swallows with different levels of nest defence had similar probability to return from migration between two years (a proxy for survival). In one year, swallows that defended their nests more boldly were also more likely to succeed. However, nest defence was not linked to nestling weight or number of fledglings. Thus, we found no evidence of a trade-off between fitness components. It is possible that the investigated relationships become relevant only in extreme years that severely alter the costs and benefits of this behaviour.

scholarly journals Parents face quantity–quality trade-offs between reproduction and investment in offspring in Iceland

2016 ◽  
Vol 3 (5) ◽  
pp. 160087 ◽  
Author(s):  
Robert Francis Lynch
Keyword(s):  
Reproductive Success ◽  
Evolutionary Biology ◽  
Fundamental Problem ◽  
Lifetime Reproductive Success ◽  
Trade Off ◽  
Evolutionary Conflict ◽  
Trade Offs ◽  
Fitness Consequences ◽  
Using Data ◽  
Primary Impact

How to optimally allocate time, energy and investment in an effort to maximize one's reproductive success is a fundamental problem faced by all organisms. This effort is complicated when the production of each additional offspring dilutes the total resources available for parental investment. Although a quantity–quality trade-off between producing and investing in offspring has long been assumed in evolutionary biology, testing it directly in humans is difficult, partly owing to the long generation time of our species. Using data from an Icelandic genealogy (Íslendingabók) over two centuries, I address this issue and analyse the quantity–quality trade-off in humans. I demonstrate that the primary impact of parents on the fitness of their children is the result of resources and or investment, but not genes. This effect changes significantly across time, in response to environmental conditions. Overall, increasing reproduction has negative fitness consequences on offspring, such that each additional sibling reduces an individual's average lifespan and lifetime reproductive success. This analysis provides insights into the evolutionary conflict between producing and investing in children while also shedding light on some of the causes of the demographic transition.

Offspring Size and Number

2001 ◽  
Author(s):  
Frank J. Messina ◽  
Charles W. Fox
Keyword(s):  
Marine Invertebrates ◽  
Offspring Size ◽  
Fixed Amount ◽  
Trade Off ◽  
Offspring Number ◽  
Trade Offs ◽  
Primary Determinant ◽  
Survival And Reproduction ◽  
Future Reproduction ◽  
Broad Variation

If we look across all organisms, we find that some species produce only one or a few large offspring per reproductive bout (e.g., most birds and mammals), others produce 10s or 100s of intermediatesize offspring (e.g., most plants and insects), and yet others produce many 1000s of offspring (e.g., some marine invertebrates). How can we account for such broad variation? In this chapter, we review many of the environmental and demographic variables that influence the evolution of offspring size and number. In the first section, we discuss how the trade-off between offspring size and number is an important determinant of offspring size. An individual’s resources can be allocated to three basic functions— growth, somatic maintenance, or reproduction. Resources directed toward reproduction can in turn be used to produce either many small offspring or a few large offspring. Thus, for a fixed amount of resources available for reproduction, it necessarily follows that there is a trade-off between the number and size of offspring during a given bout of reproduction. Trade-offs between offspring size and number during a single reproductive bout are a primary determinant of offspring size for most semelparous organisms, which reproduce once in their lifetime (e.g., salmon and century plants). For iteroparous organisms, however, lifetime reproduction is divided into many discrete bouts, with intervening periods of no reproduction. Evolutionary explanations for the number and size of offspring in these organisms must also consider how reproductive effort during any one period affects future survival and reproduction. The second part of our chapter considers the evolution of offspring number among long-lived, iteroparous organisms, especially vertebrates. We focus on the clutch sizes of birds that produce altricial (nidicolous) young. Because each nestling requires much parental care, we expect strong selection toward producing the most appropriate number of offspring for a given environment. The trade-off between current and future reproduction can also affect semelparous animals if offspring must be distributed among scattered resources. Many insects, for example, lay eggs on small, discrete hosts, and their sedentary offspring often cannot move between hosts. A female that places too many eggs on a host faces the same diminishing returns as a bird that produces more nestlings than it can provision.

scholarly journals On Trade-offs and Communal Breeding The Behavioural Ecology of Agta Foragers

2021 ◽  
Author(s):  
Abigail Emma Page
Keyword(s):  
Life History Strategies ◽  
Energy Budgets ◽  
Small Scale ◽  
Network Centrality ◽  
Communal Breeding ◽  
Household Energy ◽  
Trade Off ◽  
Adaptive Value ◽  
Trade Offs ◽  
Fitness Consequences

Time is finite and no organism can avoid the allocation dilemma that this necessarily entails. A quintessential trade-off is that between parental investment and reproduction, otherwise known as the quality-quantity trade-off. However, humans may be exceptional among apes given our high quantity production of high quality offspring. This success has been argued only to be possible by breeding communally. In this thesis I explore questions surrounding trade-offs, communal breeding and their fitness consequences in a small-scale foraging society, the Agta. The first analysis examines the composition of Agta childcare using an innovative form of data collection to maximise sample sizes, previously a major limitation in hunter-gatherer research. The Agta, like many small-scale societies are prolific communal breeders. However, contra previous conclusions, juveniles and non-kin appeared to provide more allocare than grandmothers. Interactions with non-kin were associated with significant decreases in maternal workload, while interactions with siblings and grandmothers were not. The next analysis explores why both kin and non-kin behave cooperatively, finding support for kin selection among close kin and reciprocity for distant kin and non-kin allocare. Communal breeding appears to be an important mechanism to ensure enough childcare was received in the absence of other strategies to counter shortfalls in household energy budgets. The next analysis asks, what are the fitness consequences of maternal social networks and allocare? Mothers’ network centrality positively correlated with non-kin allocare as well as reproductive success, revealing the adaptive value of communal breeding. These results highlight the optimising nature of hunter-gatherer cooperation and life history strategies.

scholarly journals Environmental effects on the covariation among pace-of-life traits

2019 ◽  
Author(s):  
Anni Hämäläinen ◽  
Anja Guenther ◽  
Samantha C. Patrick ◽  
Wiebke Schuett
Keyword(s):  
Life History ◽  
Environmental Gradients ◽  
Environmental Variation ◽  
Behavioral Traits ◽  
Pace Of Life ◽  
Trade Offs ◽  
Fitness Consequences ◽  
Life Traits ◽  
Reproduction Traits ◽  
Future Reproduction

Pace-of-life syndromes (POLSs) are suites of life-history, physiological and behavioral traits that arise due to trade-offs between allocation to current and future reproduction. Traits generally show covariation that can arise from genetic and environmental influences on phenotypes and constrain the independent evolution of traits, resulting in fitness consequences and impacts on population dynamics. The notion that correlations among traits may vary among populations along environmental gradients suggests an important role for the environment in shaping and maintaining POLS. However, no synthesis has been attempted of the myriad ways in which environmental factors should influence POLS. Here, we formulate a series of hypotheses targeting the critical interfaces of the environment and life history-behaviour associations across different organisms. We discuss the hypotheses in light of findings from a systematic review of studies that measured changes in the association between behavior and life-history traits as a function of environmental conditions. The review revealed that POLS is often shaped by environmental variation, where harshness of the environment in early life has the most consistent effects on POLS. However, only partial or no effects of environmental variation were found in a number of studies, which may result from the highly variable study systems, traits, and environments studied. We highlight promising directions arising from the available studies and identify knowledge gaps that, if unaddressed, will impede progress in the field.

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.

Challenges in the Empirical Study of Global Governance Legitimacy

2018 ◽  
Author(s):  
Steven Bernstein
Keyword(s):  
Empirical Study ◽  
Global Governance ◽  
Research Agenda ◽  
Cultural Factors ◽  
Theory Building ◽  
Trade Off ◽  
Trade Offs ◽  
Different Types ◽  
Political Communities

This commentary discusses three challenges for the promising and ambitious research agenda outlined in the volume. First, it interrogates the volume’s attempts to differentiate political communities of legitimation, which may vary widely in composition, power, and relevance across institutions and geographies, with important implications not only for who matters, but also for what gets legitimated, and with what consequences. Second, it examines avenues to overcome possible trade-offs from gains in empirical tractability achieved through the volume’s focus on actor beliefs and strategies. One such trade-off is less attention to evolving norms and cultural factors that may underpin actors’ expectations about what legitimacy requires. Third, it addresses the challenge of theory building that can link legitimacy sources, (de)legitimation practices, audiences, and consequences of legitimacy across different types of institutions.

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