Development Of Life History Strategies Research Articles

Hybrid Behavior-Genetic Models of the Confounding Gene-Environment Correlations in the Development of Life History Strategy: Two Convergent Approaches

Traditional theories of development and evolutionary developmental psychology propose that early environmental experiences shape an individual’s developmental trajectory. According to the Adaptive Calibration Model (ACM), for example, calibration of speed of life history strategy to ecological cues encountered during development contributes to behavior that is conditionally adaptive to the organism’s environment. These theories emphasize the role of environmental influences and typically do not use designs that control potential genetic confounds. To address this methodological problem, the current study used a genetically informative design to test whether the phenotypic associations of parental instability and abuse with a slow life history factor were confounded by common genetic factors. We analyzed twin and singleton data from the Midlife in the United States (MIDUS) Survey using two convergent structural equation modeling approaches. Both approaches suggest that, when accounting for shared genetic variance across instability, abuse, and slow life history, some hypothesized environmental pathways between the early environmental measures and slow life history were not required. Once genetic factors were controlled, only parental instability was directly related to slow life history, while other hypothesized environmental pathways were non-significant. This suggests that developmental models that emphasize environmental and contextual pathways should control for possible genetic confounds.

Father absence, age at menarche, and genetic confounding: A replication and extension using a polygenic score.

Father absence has a small but robust association with earlier age at menarche (AAM), likely reflecting both genetic confounding and an environmental influence on life history strategy development. Studies that have attempted to disambiguate genetic versus environmental contributions to this association have shown conflicting findings, though genomic-based studies have begun to establish the role of gene-environment interplay in the father absence/AAM literature. The purpose of this study was to replicate and extend prior genomic work using the Avon Longitudinal Study of Parents and Children (ALSPAC), a prospective longitudinal cohort study (N = 2,685), by (a) testing if an AAM polygenic score (PGS) could account for the father absence/AAM association, (b) replicating G×E research on lin-28 homolog B (LIN28B) variation and father absence, and (c) testing the G×E hypothesis using the PGS. Results showed that the PGS could not explain the father absence/AAM association and there was no interaction between father absence and the PGS. Findings using LIN28B largely replicated prior work that showed LIN28B variants predicted later AAM in father-present girls, but this AAM-delaying effect was absent or reversed in father-absent girls. Findings are discussed in terms genetic confounding, the unique biological role of LIN28B, and using PGSs for G×E tests.

Relationship between childhood (un)predictability and life milestones in young Brazilians

The present study sought to investigate whether perceived family unpredictability affects the development of life history strategies in both the reproductive and somatic domains by evaluating the ages at which life milestones occurred. In this study 211 young Brazilians answered a 10-item instrument that contained future milestones, the Family Unpredictability in Childhood, and a sociodemographic questionnaire. Not all participants had already achieved the milestones. Earlier ages of giving birth to the first child, marrying, starting a family, and at first formal employment were correlated with greater unpredictability scores. Significant correlations were found more frequently for the participants who had already met the milestones. Data support the importance of the childhood environment for later development. Results suggest that data obtained based on the ages at which milestones occurred and ages at which milestones are expected to occur may present important differences with regard to the influence of environmental factors.

Butterflies Do Not Alter Conspecific Avoidance in Response to Variation in Density.

High conspecific densities are associated with increased levels of intraspecific competition and a variety of negative effects on performance. However, changes in life history strategy could compensate for some of these effects. For instance, females in crowded conditions often have fewer total offspring, but they may invest more in each one. Such investment could include the production of larger offspring, more time spent engaging in parental care, or more choosy decisions about where offspring are placed. For animals that have a relatively immobile juvenile stage, the costs of competition can be particularly high. Females may be able to avoid such costs by investing more in individual reproductive decisions, rearing young or laying eggs in locations away from other females. We tested the hypothesis that conspecific density cues during juvenile and adult life stages lead to changes in life history strategy, including both reproduction and oviposition choices. We predicted that high-density cues during the larval and adult stages of female Pieris rapae butterflies lead to lower fecundity but higher conspecific avoidance during oviposition, compared to similar low-density cues. We used a 2×2 factorial design to examine the effects of low and high conspecific density during the larval and adult stages of butterflies on avoidance behavior and fecundity. We found that past information about conspecific density did not matter; all butterflies exhibited similar levels of fecundity and a low level of conspecific avoidance during oviposition regardless of their previous experience as larvae and adults. These results suggest that P. rapae females use a fixed, rather than flexible, conspecific avoidance strategy when making oviposition decisions, and past information about conspecific density has no effect on life history and current reproductive investment. We speculate that this may be partially because past conspecific density per se is not a reliable cue for predicting current density and levels of competition, and thus it does not affect the development of life history strategies in this system.

Change across the lifespan in a psychological measure of life history strategy

Abstract Life history theory predicts that people calibrate their reproductive strategies to local levels of environmental harshness and unpredictability. While previous research has established the importance of early life cues in the development of life history strategy, the degree to which life history strategy exhibits plasticity later in life is unclear. Using longitudinal data (total N =479) from four archival studies and a recently validated psychological measure of life history strategy, we examined mean-level trends in life history strategy at the level of psychological phenotype between the ages of 7 and 60 and found that life history strategy slowed down linearly as a function of age. Highlighting the importance of sexual selection in shaping life history strategy, we also found that men had a faster life history strategy than women at all ages and that the magnitude of this difference was constant across the lifespan. Our findings suggest that life history strategy development continues even in older adulthood. We discuss the possibility that this occurs in response to the accumulation of biological and social (e.g. offspring, relationships) capital and information about local risks and incentives.

Parenting influence on the development of life history strategy

Using a newly developed measure of life history strategy, the influence of maternal and paternal sensitivity in childhood and maternal and paternal authoritative parenting in late adolescence on developing life history strategy was examined. Maternal sensitivity and maternal and paternal authoritative parenting were positively correlated with a slow LH strategy. Maternal sensitivity and maternal authoritative parenting each explained unique variance in life history strategy as measured in late adolescence. The results remained after controlling for ethnicity, sex, childhood SES, intelligence, and childhood temperament. Consistent with previous research and theory the results suggest that maternal sensitivity in early childhood affects the development of life history strategy. However, the results also suggest that significant post-pubertal plasticity in life history strategy development remains and that parental behavior continues to be influential in an individual's developing life history strategy.

Middle Childhood: An Evolutionary‐Developmental Synthesis

AbstractMiddle childhood is a crucial phase of human development characterized by a global shift in cognition, motivation, and social behavior. In this article, I review recent work on middle childhood from an evolutionary‐developmental perspective and show how contributions from a range of disciplines can be synthesized into an integrated model of this life stage. I begin by reviewing the main evolved functions of middle childhood and the underlying hormonal mechanism of adrenarche. Then, I introduce the idea that the transition to middle childhood works as a switch point in the development of life history strategies. Finally, I discuss three insights into the nature of middle childhood that arise from an integrated approach.

Asynchronic steroid activity of Leydig and Sertoli cells related to spermatogenic and testosterone cycle in Phymaturus antofagastensis

The severe environments where Phymaturus lizards inhabit in the Andes highlands and in Patagonia, Argentina, impose restrictions on their reproduction, offering a framework for the development of life history strategies to overcome hard weather conditions. Among them, prolonged female cycles, asynchrony between sexes in receptivity, and sperm storage in males, were described. Asynchrony in the reproductive timing between males and females is a consequence of different energy requirements for gametogenesis, and often imply the existence of cellular mechanisms to enhance fertilization, such as the asynchronic steroid synthesis between testicular compartments, allowing gametogenesis independently of mating. In the present study ultrastructural and hormone assays were combined for the first time in liolaemids. Specifically, morphological features of steroid activity in Leydig and Sertoli cells, and serum testosterone concentrations have been studied in the lizard Phymaturus antofagastensis. Leydig and Sertoli cells presented morphological features characteristic of steroid synthesis during the spermatogenesis, and evident asynchronic steroid production between testicular compartments. Active Sertoli cells and inactive Leydig cells were observed in spring and autumn, while in mid-summer their steroid activity was synchronic in coincidence with maximal abundance of spermatozoa in epididymis. Serum testosterone concentration was at its maximum in mid-summer (126–230 ng ml −1), and minimum in late spring (4–24 ng ml −1) and early autumn (2–17 ng ml −1). In view of these results, P. antofagastensis males show an original approach to adjust their reproductive activity to physiological and environmental constraints at high latitudes and altitudes in the Andean highlands of Argentina.

Fundamental Dimensions of Environmental Risk : The Impact of Harsh versus Unpredictable Environments on the Evolution and Development of Life History Strategies.

The current paper synthesizes theory and data from the field of life history (LH) evolution to advance a new developmental theory of variation in human LH strategies. The theory posits that clusters of correlated LH traits (e.g., timing of puberty, age at sexual debut and first birth, parental investment strategies) lie on a slow-to-fast continuum; that harshness (externally caused levels of morbidity-mortality) and unpredictability (spatial-temporal variation in harshness) are the most fundamental environmental influences on the evolution and development of LH strategies; and that these influences depend on population densities and related levels of intraspecific competition and resource scarcity, on age schedules of mortality, on the sensitivity of morbidity-mortality to the organism's resource-allocation decisions, and on the extent to which environmental fluctuations affect individuals versus populations over short versus long timescales. These interrelated factors operate at evolutionary and developmental levels and should be distinguished because they exert distinctive effects on LH traits and are hierarchically operative in terms of primacy of influence. Although converging lines of evidence support core assumptions of the theory, many questions remain unanswered. This review demonstrates the value of applying a multilevel evolutionary-developmental approach to the analysis of a central feature of human phenotypic variation: LH strategy.

Effects of Harsh and Unpredictable Environments in Adolescence on Development of Life History Strategies

The National Longitudinal Study of Adolescent Health data were used to test predictions from life history theory. We hypothesized that (1) in young adulthood an emerging life history strategy would exist as a common factor underlying many life history traits (e.g., health, relationship stability, economic success), (2) both environmental harshness and unpredictability would account for unique variance in expression of adolescent and young adult life history strategies, and (3) adolescent life history traits would predict young adult life history strategy. These predictions were supported. The current findings suggest that the environmental parameters of harshness and unpredictability have concurrent effects on life history development in adolescence, as well as longitudinal effects into young adulthood. In addition, life history traits appear to be stable across developmental time from adolescence into young adulthood.

Early social status and the development of life-history strategies in Atlantic salmon

Atlantic salmon have a variable life cycle. In good growing conditions, underyearling fish may metamorphose into the migratory smolt phase during their second spring, or delay at least a further year. The strategy adopted by particular fish appears to become fixed during their first summer. This paper examines whether either feeding efficiency or dominance in mid-summer correlates with the life-history strategy adopted. Eighty fish were individually marked and their feeding efficiency (= mean handling time for food items) and dominance rank measured under laboratory conditions in mid-July. Growth rates of the fish were then monitored over the next three months, until developmental strategies became apparent. Discriminant and logistic regression analyses revealed that both dominance rank and size attained by July were independent, significant predictors of future developmental pattern (the age at metamorphosis being correctly predicted on the basis of rank and size in 84% of cases) whereas feeding efficiency had no effect. Thus fish that were dominant or larger two months after first feeding or both had a greater probability of migrating after only one year in freshwater than those more subordinate or smaller or both.