Parental Investment Research Articles

Education gradients in parental time investment and subjective well-being

Education gradients in parental time investment and subjective well-being

Egg Size Scales Negatively With System Size in a Periodic Fish Species.

Optimal egg size theory implies that female organisms balance between fecundity and individual offspring investment according to their environment. Past interspecific studies suggest that fishes in large marine systems generally produce smaller eggs than those in small freshwater systems. We tested whether intraspecific egg size variation reflected a similar pattern by comparing egg size among yellow perch (Perca flavescens) populations inhabiting a range of system sizes. In 2018, 2019, and 2023, we collected yellow perch egg samples from 12 locations in systems ranging in surface area from 37 to 5,390,492 ha. First, we found that egg diameter significantly increased with maternal total length in five of eight individually tested populations. After accounting for these maternal effects, we found a significant interaction, where females inhabiting larger lakes, such as the main basins of Lakes Erie and Michigan, produced smaller eggs than those in smaller inland lakes, and the greatest differences were demonstrated among females of greater total length. This egg size variation in the largest females is consistent with interspecific egg size comparisons between marine and freshwater fishes. However, by examining a single species across vastly different environments, we were able to support theoretical expectations that maternal investment in offspring should vary with environmental conditions controlling early-life resource acquisition and competition.

Does Delivery Format Matter? A Pilot Study Comparing Telehealth Versus Face-to-Face Movement Interventions for Children With Autism Spectrum Disorder.

Children with Autism Spectrum Disorder (ASD) have motor, social communication, and behavioral challenges. During the pandemic, children lost access to face-to-face (F2F) services and had to revert to telehealth (TH) options. We compared the efficacy, fidelity, acceptability, and feasibility of a general motor (GM) intervention using an F2F or telehealth (TH) format. Fifteen children with ASD participated in an 8-week program involving gross motor games to promote motor and social communication skills. Differences across TH and F2F formats for motor and socially directed verbalization as well as stakeholder feedback on formats were collected. Gross motor and socially directed verbalization did not differ between the F2F and TH subgroups, and parents and trainers were satisfied with either format. However, TH interventions were longer, had more technological challenges, and required more parental effort. The findings of this study support the use of TH as a comparable and viable substitute for F2F interactions for children with ASD.

Shaping inequality and intergenerational persistence of poverty: Free college or better schools?

We evaluate the aggregate, distributional and welfare consequences of alternative government education policies to encourage college completion, such as making college free and improving funding for public schooling. To do so, we construct a general equilibrium overlapping generations model with intergenerational linkages, a higher education choice as well as a multi-stage human capital production process during childhood and adolescence with parental and government schooling investments. The model features rich cross-sectional heterogeneity, distinguishes between single and married parents, and is disciplined by US household survey data on income, wealth, education and time use. Studying the transitions induced by unexpected policy reforms we show that the “free college” and the “better schools” reform generate significant welfare gains, which take time to materialize and are lower in general than in partial equilibrium. It is optimal to combine both reforms: tuition subsidies make college affordable even for children from poorer parental backgrounds and better schools increase human capital thereby reducing dropout risk.

Male Reproductive Traits Display Increased Phenotypic Variation in Response to Resource Quality and Parental Provisioning in a Tropical Rainforest Dung Beetle, Onthophagus c.f. babirussa.

Reproductive traits that mediate differential fitness associated with mate acquisition and fertilisation success are often strongly linked to the overall condition. We investigated the effects of resource quality and parental provisioning in the phenotypic expression of sexual and non-sexual traits in a rainforest dung beetle, Onthophagus c.f. babirussa (Eschscholtz, 1822) from Singapore. F1 individuals were reared from wild-caught beetles and paired up to produce offspring (F2), and F2 larvae from the same F1 parents were reared on two dung substrates (herbivore and omnivore) in a full-sib design. Sexual traits displayed greater phenotypic variation in response to dung resource quality, with the precopulatory trait (horn length) responding more than the postcopulatory trait (testes weight). Notably, genotype-by-environment interactions between parental lines (genotype) and dung type (environment) affected male body size and horn length only, suggesting sex-specific variance in plasticity associated with sexually selected precopulatory traits. Dung type had significant effects on all measured traits. Offspring that were provisioned higher quality resource (omnivore dung) had larger absolute and relative trait values. Parental lines only significantly affected female body size but none of the male traits, suggesting an important role of environment and resource partitioning in determining precopulatory success of male offspring. Parental provisioning of larval resource varied with resource quality and brood sequence. Parents provisioned more dung when herbivore dung was presented than when they were given omnivore dung and provisioned more dung for their earlier broods when using herbivore dung but not omnivore dung. This suggests a trade-off between early offspring fitness and resource quality. We tested directly for genotype-by-environment (G × E) interactions in the expression of several morphological traits relevant to dung beetle fitness and documented that offspring with similar phenotypes may result from completely different parental resource allocation strategies. We discuss the importance of studying parental investment on trait variation and its implications on dung beetle ecology.

Increased Reproductive Output and Telomere Shortening Following Calcium Supplementation in a Wild Songbird.

Life history theory predicts increased parental investment comes with fitness costs, often expressed as negative effects on survival and future reproduction. To better understand the costs of reproduction and life history trade-offs, we evaluated calcium supplementation at a high-elevation site in Colorado as a novel approach to experimentally alter reproductive investment in nesting female Tachycineta bicolor (tree swallow). Calcium is a nutrient critical to avian reproduction as the intake of natural calcium is essential for egg production, embryo development, and nestling growth. Altering calcium availability exclusively during the breeding season allowed examination of individual biological responses to experimental modification of reproduction, as well as the reproductive costs associated with egg production and laying an entire clutch. As a functional endpoint and proxy for fitness and longevity, telomere length was measured at the beginning and end of each breeding season. Telomeres-protective "caps" at the ends of chromosomes-have been shown to shorten with aging and a variety of stressors, including higher reproductive output. Results demonstrate that tree swallow mothers supplemented with calcium during the breeding season experience higher reproductive output and produce offspring with longer telomeres, which came at the cost of relatively shorter telomeres during the reproductive season. These findings provide additional support for reproductive trade-offs, and also challenge previous calcium supplementation studies that suggest excess calcium reduces the cost of reproduction.

Characterisation of Fatty Acid Profiles in Tasmanian Atlantic Salmon Muscle, Oocytes and Eggs in Differing Fully Commercial Settings

ABSTRACTTasmanian Atlantic salmon broodstock may be conditioned in flow‐through (FT) systems where water quality fluctuates and temperatures approach their upper limit of thermal tolerance, or in recirculating aquaculture systems (RAS) where conditions are comparatively cool and stable. The impact of broad conditioning approach on the molecular cargo of salmon eggs has never been explored in dynamic commercial settings. Therefore, this study aimed to characterise the reproductive features of broodstock conditioned using different commercial approaches and determine whether the fatty acid (FA) profiles of muscle, oocytes and eggs varied between groups during vitellogenesis and at stripping. The collective conditioning approach had a marked impact on the somatic and reproductive dynamics of female salmon broodstock, and the eggs produced by each group of fish were fundamentally different in terms of their FA composition. Of particular note is the increased maternal investment of saturated FAs (mg.g−1) and monounsaturated FAs (percent and mg.g−1) by FT‐based eggs, and the higher n3 polyunsaturated FA (percent and mg.g−1), docosahexaenoic acid (DHA, percent and mg.g−1), arachidonic acid (ARA, percent), eicosapentaenoic acid (EPA, percent), n3:n6 ratio and ARA:EPA ratio of RAS‐based eggs. These metrics combined with the apparently higher prevalence of neural development and survival of RAS embryos suggest that RAS eggs were of higher quality. On the other hand, there is evidence to suggest that FT broodstock attempt to prepare their offspring for a (presumably) challenging early life environment by producing larger eggs that are proportionally rich in short‐chain FAs and contain a higher total quantity of FAs per egg.

Behavioral responses during and after a postpartum human-animal interaction in rangeland breeding ewes

Lamb welfare, performance and survival on rangeland is partially determined by the quality of maternal care received (i.e., high durations of sniffing/grooming, allowing udder access, and staying close to the lamb). Previous studies have explored maternal behavior scores (MBSs), as a tool to select ewes based on their proximity to the lamb and the shepherd, finding variable evidence towards sensitivity and robustness in scores in ability to gauge lamb outcome (birth weight and weaning weight), survival, and maternal care throughout the lambing season. Though this scoring system is convenient, there may be another behavioral attribute related to fear of human or relationship to the human handler may be elicited during lamb collection and processing. This longitudinal study investigated the presence of a trait in response to the human handler employing a Lamb Handling (during processing) and a Lamb Tie Down (after processing) test with N= 42 total ewes and n=26 ewes consistently present across both years of the study. The current study also set out to investigate the relationship between proximity to the shepherd and lamb outcome. Attempts to perform principal component analysis revealed that variables from the Lamb Handling and Lamb Tie down test were not suitable for factor analysis. In the Lamb Handling test, proportion of ‘pacing’ was a nearly significant, negative predictor (P=0.07) term in the binary ‘investigating human’ model, improved model fit and explained more variance compared to the null model [(cumulative weight: 90 vs 10 %); (R2adjusted: 30.8 vs 15.2 %; deviance= 31 vs 18.5 %)]. A random term for individual also improved fit in this model, indicating a potential behavioral trait driven by the ewe related to fear or perception of the human. The occurrence of grazing (0 or 1) was a nearly significant, positive predictor (P=0.06), improved model fit and explained more variance in the ‘investigating human’ model compared to the null model [(cumulative weight: 76 vs 24 %); (R2adjusted: 21 vs 15.2 %; deviance= 26.8 vs 18.5 %)]. Individual did not improve model fit in the relationship between ‘investigation human’ and ‘grazing’. Weaning weights were a nearly significant positive predictor in the model for ‘close proximity’ at lamb collection (P=0.07) and a significant positive predictor for ‘close proximity’ during processing (P<0.001), however, did not improve model fit over the null. Birth weights improved model fit for behaviours including ‘sniffing/grooming’ and ‘pawing’ in the Lamb Tie Down test and these behaviours may have been moderated by maternal investment in heavier lambs. Behavioural responses, expanding beyond proximity measures, can be useful for gauging maternal attachment and investment in the lamb during and after processing. Fear or perception of humans should also be considered as contributors to the response to the shepherd during human-animal interactions in the lambing season.

Bullying Prevention Practices and Child Stress in Public Elementary Schools

This quantitative study employed surveys to assess the extent of bullying prevention efforts from schools and parents, and to measure levels of child stress in terms of distress, lack of well-being, and absence of social support. The sample consisted of students from multiple public elementary schools. Data were analyzed using mean, standard deviation, correlation coefficients, and regression analysis. The study found that both school and parental bullying prevention efforts were very extensive. Child stress levels were generally low across various indicators. A significant negative relationship was found between bullying prevention practices and child stress, indicating that effective prevention efforts are associated with reduced stress levels in children. Both school-based and parental efforts were identified as significant predictors in reducing child stress. The findings suggest that comprehensive bullying prevention efforts are effective in reducing child stress. The study emphasizes the importance of a multi-faceted approach involving both schools and parents in bullying prevention programs. The study concludes that effective bullying prevention practices are associated with lower levels of child stress, highlighting the need for collaborative efforts between schools and parents. Recommendations are made for researchers, the Department of Education, school heads, and teachers to enhance bullying prevention programs.

Teenage childbearing and the welfare state

Abstract Teenage childbearing is a common incident in developed countries. However, teenage births are much more likely in the USA than in any other industrialized country. Most of these births are delivered by female teenagers from low-income families. The hypothesis put forward here is that the welfare state (a set of redistributive institutions) has a significant influence on teenage childbearing behavior. We develop an economic theory of parental investments and the risky sexual behavior of teenagers. The model is estimated to fit stylized facts about income inequality, intergenerational mobility, and the sexual behavior of teenagers in the USA. The welfare state institutions are introduced via tax and public education expenditure functions derived from US data. In a quantitative experiment, we impose Norwegian taxes and education spending in the economic environment. The Norwegian welfare state institutions go a long way in explaining the differences in teenage birth rates between the USA and Norway.

“Our Children Are Dead”: Past and Anticipated Adversity Shaping Caregiving and Cultural Reproduction among Banyamulenge Refugee Families in Rwanda

It is well known that experiences of extreme adversity strongly impact caregiving and family dynamics. In this study, we explore how caregiving is shaped by experiences of war and displacement among a community experiencing protracted, ongoing conflict and displacement, namely, Congolese Banyamulenge refugee families in Rwanda. The findings are based on six months of ethnographic team research with Banyamulenge refugee families living in semi-urban southern Rwanda. Among the caregivers, including people who arrived several years ago and others who have lived in Rwanda for over two decades, we found a strong longing for home and past cattle-herding life. We also found that caregivers emphasized the transmission of “survival tactics” as well as Banyamulenge identity and culture. We argue that these caregiving objectives and practices speak to the community’s experiences of material and existential losses in the past, as well as those anticipated in the unknown future. Second, parental caregiving efforts appear to lead to increased intergenerational dissonance, with children wishing to integrate into their host community. While this finding appears in line with much of the migration literature about intergenerational family relationships and conflict, we find that children’s orientation is not only informed by the host environment but also stems from a desire to relieve their parents’ suffering from loss and help them invest in more optimistic futures. Finally, while our findings suggest profound changes in social and cultural reproduction in the long term, we argue for caution, as ongoing changes in war dynamics in DR Congo may inform shifts in ideas on belonging among the children. The findings provide new insights for understanding how caregiving may be affected by war and displacement while effecting change in war-affected, displaced communities.

Revealing the key signals in nestling begging behavior perceived by parent birds during parent-offspring conflict.

The parent-offspring conflict in avian species encompasses resource allocation and a balance necessary for survival for both parties. Parental investment is modulated according to various factors, among which begging is important. Endogenous hormones, particularly corticosterone (CORT), play a role in modulating begging behavior. However, most studies on hormonal regulation of begging behavior induced elevated hormone levels in the offspring through feeding or injections, thus, limiting our knowledge of the evolution of the parent-offspring conflict under natural conditions. In this study, we aimed to identify the key signals that parents respond to during interactions with their nestlings in the wild, considering factors such as endogenous hormone CORT, nestling age, and brood size, which may affect nestling begging behavior. Begging performance was evaluated by measuring the begging frequency and score of the red-whiskered bulbul (Pycnonotus jocosus), along with assessing CORT levels in feathers. CORT levels were significantly correlated with both the begging frequency and score of nestlings, while variables such as body mass and tarsus length did not influence parental feeding frequency. Additionally, factors such as the number of nestlings (brood size), age, and begging frequency were predictors of parental feeding frequency. Our findings indicate that begging frequency, nestling age, and brood size are signals that help navigate the intricacies of the parent-offspring conflict and that parents may rely on these key signals from the range of begging cues exhibited by nestlings to adjust their feeding strategies.

Variance partitioning of nest provisioning rates in blue tits: individual repeatability, heritability, and partner interactions.

In many animal species, including most birds, parental care is performed by both parents, which has important implications for mate choice (good parent hypothesis) and parental investment strategies. Partitioning the variance in measures of parental care into heritable and nonheritable components is important to understand the evolvability of parental investment and its potential role in mate choice. We employed an automated system to monitor provisioning behavior at 817 blue tit nests over 10 years (totaling ~3 million visits). Daily provisioning rates of males and females were moderately repeatable between years (Radj = 0.16 and 0.15, respectively), which was almost entirely explained by additive genetic effects. While this degree of heritability is sufficient for parental investment to respond to selection, we argue that the modest level of repeatability provides limited potential for a "provisioning phenotype" to be used as a criterion in mate choice. Daily visit rates were positively correlated between pair members, but after accounting for shared environmental factors, this relationship became clearly negative, thereby providing support for models of partial compensation. Visit rates also differed substantially between years, and between days within a year. Thus, it is important to account for these variables when comparing the parental investment between individuals. Our results highlight the interplay between genetic, social, and environmental influences on provisioning behavior.

Parental Investment, Status, and Child Gender: Some Evidence for the Trivers–Willard Hypothesis from a Survey Experiment

This study critically evaluates and empirically tests the Trivers–Willard (TW) hypothesis, which proposes a relationship between parental socioeconomic status and sex: Parents with higher status are expected to be more likely to have male offspring and to preferentially invest in male offspring, whereas parents with lower status are expected to be more likely to have female offspring and to preferentially invest in daughters. Although the TW hypothesis has been explored in terms of offspring sex ratio and parental investment, findings in modern developed societies generally show null results, with notable exceptions in the domain of parental investment in their children’s education. Previous studies have often not explicitly addressed the potential underlying mechanisms of the TW effect. This includes the authors of the original hypothesis (Trivers and Willard 1973), who discussed some potential mechanisms but ultimately left the question of mechanisms unanswered. Building on Matthews’s (2011) proposition to explore psychological underpinnings, this paper posits that the TW effect, if present, may be rooted in general parental preferences. To investigate this, a factorial survey experiment was designed to measure respondents’ preferences in parental investment while minimizing social desirability bias. The study specifically examines the extent to which respondents’ assessments of favorability and fairness in various parental investment scenarios depend on child characteristics believed to influence differential parental behavior. The findings reveal patterns that are somewhat in line with the TW hypothesis but are minor and lack statistical significance. The article concludes by proposing three future research directions aimed at further unraveling the intricacies of the TW effect.

Analysis of Parental Investment Mode of Multi-child Families in China——The Influence of Sex and Age on Parents' Investment Choice

With the progress of society and economic development, the quality and quantity of parental investment have an important impact on the future achievements of children. This study will use questionnaires and interviews to explore the specific effects of child gender and age on parental investment choice in multi-child families, and analyze the history of parental investment, problems, challenges, and impacts in multi-child families. The research shows that the parental investment mode of parents in their children tends to be diversified and personalized; the possible problems include economic pressure, educational pressure, family relationship pressure and emotional investment imbalance; the gender and difference may challenge the shaping of mate selection and parenting concept; and the influence aspects include economic pressure, educational resources and change of family relationship.

Impact of Parental Time Investment on Child Development among Dual Income Family

This cross-sectional study investigates how early childhood development is impacted by parental time commitment in the Horizon Hill dual-income family community. This study employs quantitative method approach to examine how changes in parental engagement dynamics affect children's behavior, mental health, and cognitive functioning both before and after the intervention. The results demonstrate that families have a great involvement rate, with 10 out of 11 demonstrating a strong dedication to enhancing their children's developmental experiences through the program's seamless integration into their daily routines. The results also show that advances in children's cognitive, social, emotional, and behavioral dimensions positively correspond with higher parental investment. These findings highlight how important parental participation is in helping Horizon Hill neighborhood children have great early experiences. This study has ramifications that go beyond improving child well-being and encouraging good parenting techniques through community-based interventions. By comprehending how parental time investment affects child development, policymakers and practitioners can create focused initiatives that enable parents to create caring environments that support their kids' development and success. This study adds to our understanding of the dynamics of parent-child relationships and emphasizes how important it is to spend quality time raising children to promote positive developmental outcomes.

Variation in parental investment preferences for nestlings of the Gray‐backed Shrike (Lanius tephronotus) in alpine environments

AbstractIn the northeastern edge of the Qinghai‐Tibet Plateau, the Gray‐backed Shrike, a shrubland bird species of the plateau, confronts harsh living conditions. The impact of such an environment on their reproductive strategies has long intrigued us. This study reveals significant environmental effects on the investment of the Gray‐backed Shrike during their nestling‐rearing and egg‐laying stages. (1) Based on measurements of 215 shrike eggs from 2017 to 2021, we found that under the cold alpine climate, Gray‐backed Shrikes opt for a strategy of larger clutches and bigger eggs as average rainfall decreases. Concurrently, parents display a decreasing hatching order strategy, resulting in significant weight differences among newly hatched nestlings. (2) Marginal and core offspring exhibited no significant differences in fledging conditions. Core offspring generally have a slightly larger physique than marginal ones. However, marginal offspring exhibit the highest growth rate, with similar survival rates across different offspring categories. Parental rearing adopts a nest survival strategy. (3) The food provisioning rate by parents correlates strongly with the number of nestlings, the age of the nestling, and the nest's sex ratio. Differences exist between female and male provisioning rates based on begging intensity and average temperature; higher average temperatures lead to more food, with males providing more food. (4) Factors like nest sex ratio, offspring category, nestling age, and nestling sex influence the feeding preferences of parents. When overall nestling ratios skew towards either male or female, parental feeding preferences align with the actual nest sex ratio. Male and female parental feeding preferences differ based on average temperature and nestling sex. Males consistently exhibit a stronger preference for feeding male nestlings, regardless of the nest's sex ratio. In contrast, females don't show a clear preference, leading to differences in survival rates for different nestling sex under male feeding preferences.

Food supplementing peregrine falcon (Falco peregrinus tundrius) nests increase reproductive success with no change in mean parental provisioning rate.

Parents are expected to exhibit intermediate levels of investment in parental care that reflect the trade-off between current versus future reproduction. Providing parents with supplemental food may allow for increased care to the current brood (additive model), re-allocation of parental effort to other behaviours such as self-maintenance (substitution model), or may provide parents with a buffer against provisioning shortfalls (insurance model). We investigated the impact of parental food supplementation on provisioning behaviour and breeding success in Arctic-breeding peregrine falcons (Falco peregrinus tundrius) over five successive breeding seasons (2013-2017). We found that supplemental feeding had no impact on mean provisioning rates, yet resulted in increased nestling survival probability, increased nestling body mass and decreased variance in nestling body mass and provisioning rates. These results are consistent with parents adopting a hybrid of the additive and substitution models. We suggest that food supplementation enables increased investment in other forms of parental care (e.g. nest defence, brooding) without altering mean provisioning rates. The lack of observed effects on mean provisioning rates, coupled with increased survival and body mass of offspring, suggests a potential reallocation of parental effort. The findings contribute to understanding the responses of peregrine falcons to food supplementation, highlighting the need for future studies to explore broader environmental contexts and potential long-term effects on parental survival and future reproduction.

Maternal risk-management elucidates the evolution of reproductive adaptations in sharks by means of natural selection

Maternal investment theory is the study of how breeding females allocate resources between offspring size and brood size to achieve reproductive success. In classical trade-off models, r/K-selection and bet-hedging selection, the primary predictors of maternal investments in offspring are population density and resource stability. In crowded, stable environments, K-selected females invest in large offspring at an equivalent cost in brood size. In uncrowded, unstable environments, r-selected females invest in large broods at an equivalent cost in offspring size. In unpredictable resource environments, bet-hedging females invest moderately in brood size and offspring size. The maternal risk-management model represents a profound departure from classical trade-off models. Maternal investments in offspring size, brood size, and brood number are shaped independently by autonomous risk factors: the duration of gaps in resources during seasonal cycles, rates of predation, and unpredictable catastrophic events. To date, no single model has risen to a position of preeminence. Here in sharks, we show that maternal investments within and across species do not agree with the predictions of trade-off models and instead agree with the predictions of the maternal risk-management model. Within and across shark species, offspring size and brood size were independent maternal investment strategies. The risk of starvation favored investments in larger offspring. The risk of predation favored investments in larger broods. If empirical studies continue to confirm its predictions, maternal-risk management may yet emerge as a unifying model of diverse reproductive adaptations by means of natural selection.

Brooding duration does not depend on cat predation risk but is related to weather and phenology in the wandering albatross (Diomedea exulans).

Parental investment increases offspring fitness at the expense of the parent's ability to invest in other offspring. In many animal species, parents guard their offspring after birth. The parental decision over the duration of this period is expected to be triggered by the associated fitness costs and benefits for both offspring and parents. Here, we evaluated the relevance of several intrinsic and environmental variables in determining brooding period duration in the wandering albatross (Diomedea exulans) and questioned whether brooding duration was related to chick subsequent survival and biometry prior to fledging. We used a semi-experimental design to increase the variance in cat abundance, a recent predator of albatross chicks, and predicted that an increased predation risk at the nest scale would trigger longer chick brooding and thus, protection. In addition, we questioned the influence of weather conditions, hatching date, and characteristics of chicks (sex and biometry) and parents (sex and age) on brooding duration. We report no effect of predation risk or parental characteristics on brooding duration. However, the probability for a parent to end brooding decreased with forthcoming unfavorable weather. Our data also revealed reduced brooding duration for late-hatched chicks and a positive association between brooding duration and chick structural size, and between the frequency of shifts between parents and chick structural size. Finally, brooding duration was not associated with chick survival or with chick biometry prior to fledging. We discuss these results in light of pre-existing hypotheses on fitness costs and benefits associated with brooding duration for chicks and parents.