Parental care is a critical component of many breeding systems that enhances both parent and offspring fitness. It is widely recognized that parental care varies in quality and quantity in response to variation in offspring need, parental condition, and ecological context. One context that has been underexplored, however, is the difference in parental care between day and night, with many parental care studies focused on diurnal care. To fully understand the evolution of parental care, the costs and benefits and the negotiations between parents, both diurnal and nocturnal care must be accounted for. Here, we show that nocturnal parental care exists in the clownfish Amphiprion percula, with males and females actively caring for offspring at night throughout embryo development and during hatching in a laboratory setting. At night, as during the day, males are the dominant caregivers and both parents increase care as embryos mature. At night, in contrast to the day, females provide substantially more care. This increase in energy expended by parents on care may be a mechanism to increase dissolved oxygen in the water at night, improving embryo survival. We also document the existence of three new nocturnal parental care behaviors, not previously seen during the day: vigorous fanning, vigorous mouthing, and anemone biting. These behaviors are particularly frequent during hatching, and although they are not necessary for hatching to occur, they may serve to enhance the embryos’ successful transition from the benthos to the water column. This study contributes to our understanding of parental care, demonstrating the importance of considering nocturnal care if we are to gain a complete understanding of the evolution of parental care. / 2023-03-16T00:00:00Z

Yes / Early life is associated with high vulnerability to morbidity and mortality - risks which can be reduced in infancy and early childhood through strategically high levels of parental or alloparental investment, particularly in the case of maternal breastfeeding. Recent evidence has supported links between early-life health and care patterns and long-term population health. This growing body of research regarding the broader impacts of infant-parent interactions transcends a traditional partitioning of research into discrete life stages. It also highlights implications of childhood data for our understanding of population health and behaviour. Skeletal and environmental data indicate that the 5-7th century cemeteries at Littleport and Edix Hill (Barrington A), Cambridgeshire represent populations of similar material culture but contrasting environments and health. The high prevalence of skeletal stress markers at Littleport indicates a community coping with unusual levels of biological stress, potentially a consequence of endemic malaria present in the marshy Fen environs. In contrast, Edix Hill was an inland site which exhibited lower skeletal stress marker prevalence comparable to wider British data for the early medieval period. Early life patterns relating to diet and physiological stress at Littleport (n=5) and Edix Hill (n=8) were investigated through analyses of carbon and nitrogen stable isotopes from incrementally-sampled deciduous dentine. Meaningful variation in isotopic values within and between populations was observed, and should be a focus of future interdisciplinary archaeological childhood studies. / The Society for the Study of Human Biology, the Durham University Institute of Medieval and Early Modern Studies, and by the Rosemary Cramp Fund.

Muitas formas de cuidado parental aumentam a sobrevivência da prole, ao custo de uma diminuição na capacidade dos pais em investir em proles futuras. Espera-se, portanto, que indivíduos parentais adotem estratégias de cuidado que lhes permitam balancear benefícios imediatos e custos futuros, otimizando seu sucesso reprodutivo total. Nesta dissertação, testamos um potencial custo e um benefício do cuidado maternal do opilião Neosadocus maximus, espécie cujas fêmeas desertam suas desovas periodicamente e acrescentam ovos a elas por um período de até duas semanas características únicas entre opiliões com cuidado maternal. Exploramos também quais fatores permitem a deserção temporária das fêmeas de N. maximus. Mais especificamente, testamos as seguintes hipóteses: (1) o cuidado maternal protege os ovos contra predadores, que são mais comuns no período noturno; (2) o cuidado maternal diminui a fecundidade imediata da fêmea; (3) a camada de muco que as fêmeas depositam sobre seus ovos mantém a prole protegida nos momentos de deserção temporária. Nossos resultados apontam que o cuidado maternal é uma proteção eficaz contra o ataque de predadores, sem afetar negativamente a fecundidade imediata das fêmeas. Demonstramos também que a camada de muco mantém os ovos relativamente protegidos na ausência da fêmea guardiã, permitindo que estas se ausentem de suas desovas sem deixar a prole totalmente vulnerável. Sendo assim, a camada de muco que recobre os ovos de N. maximus permite que estas fêmeas minimizem os custos fisiológicos associados ao cuidado maternal sem, entretanto, aumentar os custos da deserção em termos de redução de prole provocada por predação. / Many forms of parental care increase offspring survival, at the cost of a decrease in the parental individuals capacity to invest in a future brood. It is expected, therefore, that parental individuals adopt parental strategies that allow them to balance immediate benefits and future costs, optimizing their total reproductive success. In this thesis, we aimed to identify costs and benefits of maternal care in the harvestman Neosadocus maximus, whose females periodically desert their broods and add eggs to their clutches for up to two weeks unique characteristics among harvestmen with maternal care. We also explored which factors allow N. maximus females to desert their clutches frequently. We tested the following hypothesis: (1) maternal care protects the eggs against predators, especially at night; (2) maternal care decreases the current female fecundity; (3) the mucus coat covering the eggs protects them against predators even in the absence of the guarding female. Our results indicate that maternal care is an effective protection against egg predators, and does not decrease current female fecundity. We also demonstrated that the mucus coat provides effective protection to the eggs in the absence of the guarding female, allowing them to abandon periodically their clutches without leaving the offspring completely vulnerable to predators. The mucus coat covering N. maximus eggs allows these females to minimize the physiological costs of caring, with no severe increase in the cost of deserting in terms of brood reduction by predation.

Environmental gradients can help shed light on the evolution of life history strategies such as parental investment. Parental investment is crucial for the fitness of many species. In this thesis, I examine reproductive investment dynamics in the Eurasian blue tit (Cyanistes caeruleus) in the French Pyrenees and assess potential differences in reproductive measures across an altitudinal gradient that creates variation in environmental “harshness”. Further, I investigate fine-scale aspects of bi-parental care, such as investment tactics in current reproduction, and sex differences in contributions to offspring care. To do so, I used a mixture of observational and experimental data, collected over a total of six breeding seasons from over 500 blue tits nests. I showed that breeding conditions are “harsher” due to colder temperatures with increasing elevation, leading to changes in reproductive timing and output. I found that increasing altitude leads to decreased hatching success. Nevertheless, clutch size and brood mortality is comparable across the gradient. A shift to a lower, but qualitatively comparable reproductive output may be part of a slower “pace of life” strategies pursued at high relative to low altitudes. From experimental data, I also found that parental investment is positively linked across different phases within one reproductive attempt. Finally, in line with theory, a temporary brood manipulation revealed that parents balance the benefits and costs of reproduction by partially compensating for changes in brood size. Parents also responded in similar ways to brood size. Overall, the findings presented in this thesis highlight the importance of mechanisms to fine-tune reproduction to maximise reproductive fitness. I suggest that initial reproductive decisions such as timing and amount of offspring produced heavily shape the success of a reproductive attempt. These results have implications for current versus future reproductive trade-offs in life history theory, in particular for short-lived species.

Muitas formas de cuidado parental aumentam a sobrevivência da prole, ao custo de uma diminuição na capacidade dos pais em investir em proles futuras. Espera-se, portanto, que indivíduos parentais adotem estratégias de cuidado que lhes permitam balancear benefícios imediatos e custos futuros, otimizando seu sucesso reprodutivo total. Nesta dissertação, testamos um potencial custo e um benefício do cuidado maternal do opilião Neosadocus maximus, espécie cujas fêmeas desertam suas desovas periodicamente e acrescentam ovos a elas por um período de até duas semanas características únicas entre opiliões com cuidado maternal. Exploramos também quais fatores permitem a deserção temporária das fêmeas de N. maximus. Mais especificamente, testamos as seguintes hipóteses: (1) o cuidado maternal protege os ovos contra predadores, que são mais comuns no período noturno; (2) o cuidado maternal diminui a fecundidade imediata da fêmea; (3) a camada de muco que as fêmeas depositam sobre seus ovos mantém a prole protegida nos momentos de deserção temporária. Nossos resultados apontam que o cuidado maternal é uma proteção eficaz contra o ataque de predadores, sem afetar negativamente a fecundidade imediata das fêmeas. Demonstramos também que a camada de muco mantém os ovos relativamente protegidos na ausência da fêmea guardiã, permitindo que estas se ausentem de suas desovas sem deixar a prole totalmente vulnerável. Sendo assim, a camada de muco que recobre os ovos de N. maximus permite que estas fêmeas minimizem os custos fisiológicos associados ao cuidado maternal sem, entretanto, aumentar os custos da deserção em termos de redução de prole provocada por predação. / Many forms of parental care increase offspring survival, at the cost of a decrease in the parental individuals capacity to invest in a future brood. It is expected, therefore, that parental individuals adopt parental strategies that allow them to balance immediate benefits and future costs, optimizing their total reproductive success. In this thesis, we aimed to identify costs and benefits of maternal care in the harvestman Neosadocus maximus, whose females periodically desert their broods and add eggs to their clutches for up to two weeks unique characteristics among harvestmen with maternal care. We also explored which factors allow N. maximus females to desert their clutches frequently. We tested the following hypothesis: (1) maternal care protects the eggs against predators, especially at night; (2) maternal care decreases the current female fecundity; (3) the mucus coat covering the eggs protects them against predators even in the absence of the guarding female. Our results indicate that maternal care is an effective protection against egg predators, and does not decrease current female fecundity. We also demonstrated that the mucus coat provides effective protection to the eggs in the absence of the guarding female, allowing them to abandon periodically their clutches without leaving the offspring completely vulnerable to predators. The mucus coat covering N. maximus eggs allows these females to minimize the physiological costs of caring, with no severe increase in the cost of deserting in terms of brood reduction by predation.

Dans cette thèse, j'examine la dynamique de l'investissement parental et la fitness chez la mésange bleue eurasienne (Cyanistes caeruleus) dans les Pyrénées françaises, et j'évalue les différences potentielles dues à un gradient altitudinal qui crée une variation de "dureté" environnementale. J'ai utilisé de données observationnelles et expérimentales, recueillies de plus de 500 nids de mésanges bleues. Les conditions de reproduction sont " plus dures " en cas de températures plus froides et d'une élévation croissante. J'ai trouvé que l'altitude croissante conduit à une diminution du succès de l'éclosion. Néanmoins, la taille des couvées et la mortalité des couvées sont comparables à travers le gradient. Je suggère que les décisions initiales en matière de procréation, telles que le moment et la quantité de progéniture, déterminent fortement le succès d'une tentative de reproduction. Ces résultats ont des implications pour notre compréhension du succès de reproduction. / In this thesis, I examine parental investment and fitness in the Eurasian blue tit (Cyanistes caeruleus) in the French Pyrenees and assess potential differences due to an altitudinal gradient that creates variation in environmental "harshness". I used observational and experimental data, collected from over 500 blue tit nests. Breeding conditions are "harsher" due to colder temperatures with increasing elevation. I found that increasing altitude leads to decreased hatching success. Nevertheless, clutch size and brood mortality is comparable across the gradient. I suggest that initial reproductive decisions such as timing and amount of offspring produced heavily shape the success of a reproductive attempt. These results have implications for understanding reproductive success.

Mondialement, l’infanticide est une cause importante de mortalité infantile. Dans ce mémoire, les infanticides sont analysés en fonction du statut parental, du mode de décès et de l’âge de l’enfant. La première hypothèse de ce mémoire propose qu’il y ait une surreprésentation des parents non biologiques dans les cas d’infanticides chez les enfants de moins de douze ans, et ce, en regard des taux de base de la population. L’hypothèse 2 prédit que les infanticides des parents biologiques devraient revêtir un caractère plus létal (utilisation d’arme à feu, empoisonnement, etc.) que ceux des parents non biologiques qui devraient être caractérisés principalement par des mauvais traitements et de la négligence. D’autres hypothèses sont examinées en fonction des taux de suicide et du sexe de l’agresseur. La présente étude porte sur les cas d’infanticides d’enfants de douze ans et moins sur le territoire du Québec provenant des archives du bureau du coroner pour la période se situant entre 1990 et 2007 (n=182). Les résultats obtenus appuient partiellement l’hypothèse 1 et confirment l’hypothèse 2. En ce sens, les résultats de cette étude viennent appuyer les hypothèses évolutionnistes qui soutiennent une influence du statut parental sur le comportement de l’infanticide. De façon générale, ces résultats mettent en lumière les différences qualitatives qui existent entre les parents biologiques et les parents non biologiques dans les cas d’infanticides. Les implications des résultats obtenus sont discutées. / Infanticide is considered as being an important part of infantile mortality. In this study, infanticide is studied according to the parental status (biological parent versus non biological parent), method of death and differential rates of suicide. The first hypothesis proposed that there should be an over-representation of the non biological parents in the homicide cases with the children of less than twelve years and this in look of the population rates. The second hypothesis proposed that the murders of the biological parents should clothe a more final character (weapon usage to fire, poisoning) that the homicides of the non biological parents that should be principally characterized by bad treatments. Other hypotheses are examined according to the rates of suicide and of the sex of the aggressor. The present study is based on the cases of homicides of child under the age of twelve on the territory of the Quebec from 1990 to 2007 (N = 182). The results support partially the hypothesis 1 and confirm the hypothesis 2. In this direction, the results of this study come to support the evolutionist hypotheses that principally are based on the theory of the parental investment. Implications of the obtained results are discussed.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / A depressão pós-parto (DPP) é uma condição prevalente que afeta globalmente as mulheres puérperas. Uma hipótese evolutiva aborda a depressão, e consequentemente a DPP, como uma resposta proveniente da evolução do comportamento humano ao longo da História, através da seleção natural. A teoria do investimento parental sugere que os pais não investem automaticamente em toda prole; o investimento é direcionado para que o sucesso reprodutivo seja máximo. No caso de os riscos superarem os benefícios reprodutivos, sintomas de depressão se desenvolvem como sinal de alerta. O objetivo do estudo foi identificar fatores associados à DPP que fossem compatíveis com a teoria do investimento parental. Estudo transversal realizado com 811 mães de lactentes até cinco meses de idade, no município do Rio de Janeiro. A presença de DPP foi definida com base no escore da Escala de Edinburgh (EPDS). Fatores potencialmente associados à DPP foram analisados através de regressão logística com ajuste para fatores de confundimento. Os fatores significativamente associados à DPP foram: apoio social inadequado (OR 3,38; IC 95% 2,32-4,94), baixa escolaridade (OR 2,82; IC 95% 1,69-4,70), violência física entre parceiros íntimos na gestação (OR 2,33; IC 95% 1,56-3,47), idade materna inferior a 35 anos (OR 2,20; IC 95% 1,05-4,64), falta de companheiro (OR 1,90; IC 95% 1,16-3,12), internações durante a gestação (OR 1,87; IC 95% 1,12-3,14) e prematuridade do recém-nascido (OR 1,87; IC 95% 1,02-3,42). Em suma, identificamos alguns fatores associados à DPP que podem ser úteis no rastreamento e acompanhamento de mulheres de risco. Alguns dos fatores associados à DPP podem ser explicados através das hipotéses evolutivas contempladas neste estudo. Entretanto, os achados encontrados não são suficientes para esgotar o conhecimento referente a esta questão. Futuras pesquisas devem focar em diferentes abordagens desta condição e acompanhamento das consequências para as mulheres e suas famílias. / Postpartum depression (PPD) is a prevalent condition that affects women globally after they have given birth. An evolutionary hypothesis deals with depression, and consequently PPD, as a response from the evolution of human behavior throughout history, through natural selection. The parental investment theory suggests that parents do not automatically invest in all offspring, so that the investment is directed towards maximum reproductive success. If the risks outweigh fittness benefits, symptoms of depression develop as a warning sign. The objective of the study was to identify factors associated with PPD that were consistent with parental investment theory. Cross-sectional study with 811 mothers of infants up to five months of age in the municipality of Rio de Janeiro. The presence of PPD was defined based on scores on the Edinburgh Scale (EPDS). Factors potentially associated with PPD were analyzed by logistic regression with adjustment for confounding factors. Factors significantly associated with PPD were: inadequate social support (OR 3,38; 95% CI 2,32-4,94), low educational level (OR 2,82; 95% CI 1,69-4,70), physical violence between partners in gestation (OR 2,33; 95% CI 1,56- 3,47), maternal age under 35 years (OR 2,20; 95% CI 1,05-4,64), lack of partner (OR 1,90; 95% CI 1,16-3,12), hospitalization during pregnancy (OR 1,87; 95% CI 1,12- 3,14) and prematurity of the newborn (OR 1,87; 95% CI 1,02- 3,42). In summary, we identified factors associated with PPD which can be useful in tracking and monitoring women at risk. Some of the factors associated with PPD can be explained through the evolutionary hypotheses considered in this study. However, the findings are not sufficient to exhaust the knowledge regarding this question. Future research should focus on different aspects of this condition and monitoring of the consequences for women and their families.

Mondialement, l’infanticide est une cause importante de mortalité infantile. Dans ce mémoire, les infanticides sont analysés en fonction du statut parental, du mode de décès et de l’âge de l’enfant. La première hypothèse de ce mémoire propose qu’il y ait une surreprésentation des parents non biologiques dans les cas d’infanticides chez les enfants de moins de douze ans, et ce, en regard des taux de base de la population. L’hypothèse 2 prédit que les infanticides des parents biologiques devraient revêtir un caractère plus létal (utilisation d’arme à feu, empoisonnement, etc.) que ceux des parents non biologiques qui devraient être caractérisés principalement par des mauvais traitements et de la négligence. D’autres hypothèses sont examinées en fonction des taux de suicide et du sexe de l’agresseur. La présente étude porte sur les cas d’infanticides d’enfants de douze ans et moins sur le territoire du Québec provenant des archives du bureau du coroner pour la période se situant entre 1990 et 2007 (n=182). Les résultats obtenus appuient partiellement l’hypothèse 1 et confirment l’hypothèse 2. En ce sens, les résultats de cette étude viennent appuyer les hypothèses évolutionnistes qui soutiennent une influence du statut parental sur le comportement de l’infanticide. De façon générale, ces résultats mettent en lumière les différences qualitatives qui existent entre les parents biologiques et les parents non biologiques dans les cas d’infanticides. Les implications des résultats obtenus sont discutées. / Infanticide is considered as being an important part of infantile mortality. In this study, infanticide is studied according to the parental status (biological parent versus non biological parent), method of death and differential rates of suicide. The first hypothesis proposed that there should be an over-representation of the non biological parents in the homicide cases with the children of less than twelve years and this in look of the population rates. The second hypothesis proposed that the murders of the biological parents should clothe a more final character (weapon usage to fire, poisoning) that the homicides of the non biological parents that should be principally characterized by bad treatments. Other hypotheses are examined according to the rates of suicide and of the sex of the aggressor. The present study is based on the cases of homicides of child under the age of twelve on the territory of the Quebec from 1990 to 2007 (N = 182). The results support partially the hypothesis 1 and confirm the hypothesis 2. In this direction, the results of this study come to support the evolutionist hypotheses that principally are based on the theory of the parental investment. Implications of the obtained results are discussed.

This basic qualitative study examines the parental investment strategies of first-generation African American rural college graduates in cultivating college student success. Extant literature has demonstrated that the role of the family is necessary to support the college student and that the investment of the parent is paramount to student college completion. Although educational attainment is an important goal for African American rural residents, research detailing strategies that cultivated student college completion among this population is needed to fill the gaps in the literature. The objectives were to discuss communication, involvement, and factors of influence to determine how these parents transferred their educational beliefs to their children and supported them through college graduation. These stories of success were told through the eyes of first-generation parents and their second-generation adult offspring. Research detailing the parental investment strategies toward college completion is necessary to inform parents, educational institutions, and rural college student completion in postsecondary institutions of the strategies necessary to ensure college success in this population. Lieberman’s transgenerational theory, along with concepts extracted from parental investment as it relates to education, provided the conceptual lens for the study. Data collected through interviews and documents were analyzed utilizing content analysis. Ten semistructured interviews were conducted with parents and their adult offspring. Interviews gleaned the lived experiences of the participants. Data analysis revealed six themes: (a) Catch Them Early, (b) Set the Tone, (c) Keep Them Busy, (d) Don’t Let Them “Break Rank,” (e) Encourage Advancement, and (f) Tell the Generations. The findings support the importance of developing a family investment team, how a return on parental investment occurs, making use of rural extracurricular programming, and transferring positive beliefs regarding higher education.