Most theoretical models predict an optimal offspring size that maximises parental fitness. Variation in the quality of the offspring environment can result in multiple offspring size optima and therefore variation of offspring provisioning can evolve. Variation in offspring provisioning is common and found across a variety of taxa. It can be defined as between populations, explained by optimality models, or between and within individuals, neither so easily explained by optimality models. My research focused on the evolution of variable offspring provisioning by testing theoretical models relating to variation in offspring provisioning between and within individuals. Using comparative methods, I found a positive relationship between intraclutch variation in offspring provisioning and variation in the quality of the offspring environment in a suite of pond breeding frogs. This positive relationship provided evidence that patterns of variable offspring provisioning are related to the offspring environment. This study also identified a species (Crinia georgiana) with high variation in offspring provisioning on which to focus further investigations. High variation in offspring provisioning occured between and within individuals of this species independent of female phenotype and a trade-off in offspring size and number existed. In laboratory studies, increased yolk per offspring led to increased fitness per offspring. Parental fitness calculations revealed that in high quality conditions production of small more numerous offspring resulted in higher parental fitness, but in lower quality conditions the production of large offspring resulted in the highest parental fitness. This was confirmed in field experiments under natural conditions using molecular markers to trace offspring to clutches of known provisioning, allowing me to measure exact parental fitness. The strategy of high variation in offspring size within clutches can be of benefit when the future of the offspring environment is not known to the parents: as a form of bet-hedging. Further study of the offspring environment revealed that conditions such as density dependent fitness loss, spatial variation in habitat quality, and non-random offspring dispersal, can combine to create the conditions predicted by theoretical models to maintain a strategy of variable offspring provisioning in the population. My research provides a comprehensive empirical test of the theory of variable offspring provisioning

The Silver Gull is a small gull (265 - 450g), which exhibits sexual dimorphism, with males larger than females. It has a protracted laying period of about 8 months over the winter on Penguin Island in Western Australia. The Silver Gull was studied on Penguin Island from 2000 to 2002. Completed clutches were removed from breeding pairs to induce repeat laying in order to determine the effect of increased reproductive effort on maternal body condition, egg production ability, offspring sex ratio and chick rearing capacity. Increased egg production had no significant effect on maternal body condition as measured by condition index, derived from mass divided by a measure of skeletal size. The seasonal period, divided into thirty-day intervals, had a significant impact on female condition index, with a decline in condition toward the end of the breeding season. While male condition also appeared to decline at the end of the season, this pattern was not significant. The initiation of laying varied between the three years of the study. The earliest occurred in 2000, which also experienced earlier rainfall than the later two years. Egg size and mass decreased throughout the breeding season although the number of eggs in a clutch did not decline. The size and mass of the eggs was significantly affected by the laying history of the parents, although this effect was dependent on the year in which the eggs were produced. The minimum interval required by Silver Gulls to replace a lost clutch is about 14 days. This interval increased from the start of the breeding season, but then declined toward the end, as summer was approaching. Laying interval increased significantly as the number of clutches produced by the parents also increased, up to 4 clutches in total. As more clutches were produced past this point, the laying interval became shorter. The probability of a replacement clutch being produced after clutch removal, declined as the clutch number increased and as the season progressed. Individuals that laid clutches with a larger mean mass were more likely to lay a replacement clutch. Increasing reproductive output caused a decline in the proportion of clutches that were replaced after clutch removal. The proportion of clutches that were replaced also varied between the years with the highest rates of replacement seen in 2000 which was also the year that experienced the earliest start in laying. The size of the original clutch in terms of its mean mass and volume was related to the size of the replacement clutch, but this relationship varied according to the timing of laying. During 2000 and 2001 male offspring predominated in the first two clutches produced by Silver Gulls. Further clutches that were produced demonstrated a sex ratio skewed toward females, the smaller sex in this species. Offspring sex ratio was close to equality in 2002 with very little effect caused by increased egg production. There was no effect of year, season or the laying history of the parents on hatching success. Growth rate in chicks was influenced by the year in which the chick hatched, the period during the season in which the chicks hatched, its sex and the laying history of the parents. The relationship between chick growth and the laying history, however, was complex with no consistent pattern emerging in terms of the performance of chicks from each treatment group. While the chicks from control groups generally grew faster than the chicks from manipulated parents, those individuals that were laid or raised by manipulated parents that had laid at least three clutches in total also performed well. Using the two main measures of reproductive success in the current study, egg production and chick rearing, those birds that were induced to lay multiple replacement clutches, were able to maintain a high level of condition and reproductive success. It is proposed that in the Silver Gull, only those individuals with a high level of condition continue to lay replacement clutches. If the female is unable to produce well provisioned eggs with a high chance of success, the breeding attempt is abandoned. Despite no loss of condition detected in female Silver Gulls with increasing clutch number, there was a significant shift in the offspring sex ratio toward females, indicating that strategies were in place to cope with the increased reproductive effort incurred as a consequence of repeat laying. Protracted laying in this species allows replacement of lost clutches only after maternal condition has been regained after laying.

Parent-offspring communication is widely regarded as having evolved to provide the parent with honest information about the hunger state of its offspring, thus enabling it to mediate conflict over resource allocation between parents and offspring. The conflict is caused by the offspring benefitting from receiving more care than the parents are selected to provide due to the costliness of care. I studied the role of parent-offspring communication as a mediator for the conflict in the burying beetle Nicrophorus vespilloides. The burying beetle is an excellent study system for this question, as the larvae, that are raised on carcasses of small vertebrates and cared for by both the male and the female beetle, beg for food from their parents with highly distinguishable begging displays. First, I examined whether offspring adjusted their begging to different classes, or individual adult beetles. I found that while the larvae did not discriminate between male and female beetles, they adjusted their care to cues indicating individual recognition of adults. Second, I tested whether begging was based on offspring size at egg stage, and found no indication that offspring adjusted their begging to improve their innate quality. Third, I examined whether parental response to begging exhibits behavioural plasticity when the internal clock for the timing of reproduction for the parent, and the demand from the larvae do not meet. I found that the parents adjusted their care based on the amount of begging exhibited by the larvae. Fourth, I investigated whether parental adjustment of care based on offspring begging incurs a reproductive cost to them. I found that the females paid a cost in fecundity, but not in the number of dispersing larvae or their own survival. My original contribution to knowledge is therefore to show through these four studies, that offspring begging is adjusted based on parental cues, and can directly affect proximate parental behaviours, and also incurs a reproductive cost to their future reproductive success, thus providing more experimental evidence for the importance of parent-offspring communication, and its implications to the evolution of parental care.

Studies in various animal species have demonstrated that stress during pregnancy can have a detrimental effect on progeny health and development throughout its postnatal life. If this were to apply to dairy cows, minimising stress in pregnant cows could be of critical importance in ensuring offspring health and welfare. However, relationships between maternal health and welfare and offspring performance have not been well investigated in dairy cattle. Traditionally management strategies for cows in late pregnancy (i.e. in the dry period) have focused on maximising milk production whilst minimising impacts on postpartum health. This may include management practices that can have a negative impact on the health and welfare of cows in the dry period itself. This project aimed to identify potential sources of stress associated with management practices in late pregnant cows, and to investigate its effects on offspring health, behaviour and welfare. A survey was conducted to investigate typical dry cow and pre-weaned calf management practices on dairy farms in the United Kingdom (UK). Data from 148 commercial UK dairy farms provided valuable information on dry cow and pre-weaning calf management. Procedures that were commonly practised but potentially stressful for dry cows included the abrupt cessation of milking and frequent changes in diet and social environment. Two experimental studies were conducted to investigate the impact of alternative management practices in late pregnancy on progeny welfare. The first experiment investigated the behavioural, physiological and metabolic responses of dry cows to industry minimum standards (H: high stocking group) compared to a more extensive space allowance (L: low stocking density). The offspring of these cows were monitored until weaning to assess their responses to typical dairy farm procedures. The second experiment was conducted on calves born to heifers from an out-wintering project. Pregnant heifers were kept either indoor or outdoor grazing (on deferred grass or kale) throughout the winter period. The health, growth and behaviour of offspring were monitored for the first 14 days of life. Limited feed-face space resulted in altered feeding patterns and increased competition at the feed-face. There was no association between dry period stocking density and the physiology and metabolism of dry cows. Maternal treatment had no impact on pre-weaned calf birth weight, health, growth, passive immunity, neonatal vigour and the majority of behavioural outcomes. However, H calves made more frequent social contact with companions compared to L calves and showed higher behavioural reactivity to weaning. Maternal high stocking density treatment and previous disease incidence in calves reduced the behavioural reactions to disbudding and the expression of pain-related behaviours. Out-wintering of pregnant heifers on kale showed no negative impact on growth compared to the indoor group, whilst out-wintering on deferred grass resulted in the lowest growth rate. However, out-wintering on deferred grass may have enhanced offspring social motivation and learning ability. This study has demonstrated potential associations between maternal experience during pregnancy, and offspring growth and behaviour. The effect of maternal treatment on offspring behaviour may be more likely to emerge in challenging situations. Further research will be needed to understand the underlying mechanisms and to reach definite conclusions, which would have implications for improving the welfare of late pregnant cows and their offspring.

This study was concerned with setting up a similar situation wherein pregnant mice had an abnormally high phenylalanine metabolism. Through physical and intellectual assessment of their offspring, it would then be possible to determine what effects the abnormal metabolism had during pregnancy and whether or not a restricted diet need be resumed at that time.

Magister Artium (Child and Family Studies) - MA(CFS) / Kinship foster care in South Africa, whereby orphaned and vulnerable children (OVC) are being cared for by their biological relatives, is increasing. The significant increase in kinship foster care has a strong correlation to the high rates of HIV/AIDS-related deaths, resulting in a high prevalence of children who are vulnerable and orphaned. Social workers are mandated to seek alternative care placements for such OVC, prioritising kinship care as opposed to foster care with non-biological families. However, such kinship foster care, in which children are likely to be placed in the care of their grandparents, as common practice in South Africa, is not without challenges relating to family dynamics, especially when foster children become teenagers.

In light of the current opioid epidemic, the past 20 years have made it clear that parental life experiences can significantly impact the behavior and neurobiology of their offspring. Preclinical studies indicate that addiction reflects the interaction of an individual’s environment, genetics, and epigenetic modifications they inherit from their parents. Epigenetic mechanisms - including DNA methylation, histone modification, and small non-coding RNAs – refer to the complex interaction between genes and the environment, which produce heritable changes in germ cells that are transmitted to offspring to ultimately influence the brain development and subsequent vulnerability to develop a substance use disorder. The overarching goal of this dissertation was to characterize the behavioral and neurobiological effects of paternal morphine exposure on addiction-related endpoints in offspring. A highly translational rodent model of paternal morphine self-administration was used to produce first-generation (F1) male and female adolescent and adult offspring. As a reference, offspring derived from morphine-exposed fathers were called morphine-sired offspring, and offspring from saline-exposed fathers were called saline-sired offspring. In chapter 2, we revealed that male morphine-sired progeny are more sensitive over time to the pain-relieving effects of morphine. In the periaqueductal grey, an important pain-related brain region, we identified gene expression changes in regulators of G-protein signaling proteins that could partly account for this phenotype. In chapter 3, we demonstrated that adult morphine-sired male offspring self-administered more morphine; were more motived to earn morphine infusions compared to controls; and had more baseline mu-opioid receptor binding in the ventral tegmental area. Next, in chapter 4, we found that a drug-abstinence period of 90 consecutive days following 60 days of morphine exposure in sires was sufficient to prevent morphine-sired males from self-administering more morphine than controls. In chapter 5, we showed that this addiction-like phenotype did not extend to adolescent male or female offspring. Lastly, in chapter 6, using the incubation of craving paradigm, we found that paternal morphine exposure significantly reduced cue-induced active lever pressing for heroin in morphine-sired males. Taken together, these results add to the growing body of literature that show paternal preconception experiences can impact behavioral and neurobiological endpoints in offspring, perhaps via a(n) epigenetically inherited mechanism(s) in the germline. / Psychology

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The present study examined the impact of adultification on the mental health of Chinese immigrant young adults. Given the emphasis of Chinese cultural norms on interdependence and filial piety, I also explored whether family obligation attitudes influence how Chinese immigrant young adults perceive adultification experiences. Findings indicated that family obligation attitudes have a moderating effect on adultifcation when adultification plays a mediating role between acculturative stress and psychological distress, and on the well-being of Chinese immigrant young adults. The findings suggested that Chinese immigrant offspring who hold very traditional familial attitudes and are highly committed to family obligations tend to reinforce the effect of acculturative stress on adultification, although acculturative stress did not significantly predict adultification experiences. In addition, the findings also indicated that when adultification experiences were at the highest level, they served to strengthen the effect of acculturative stress on mental health outcomes. According to the study findings, taking the cultural value of the emphasis on Chinese family obligation into consideration when interpreting adultification experiences and its impact on the mental health outcomes among Chinese immigrant young adults is crucial. / Ph. D.

The objective of this thesis was to determine the association between exposure to parental BD during childhood and risk of mood disorder. Offspring of one parent with BD completed annual clinical assessments as part of a 16-year prospective cohort study. Clinical data in the parents from Ottawa and Halifax were mapped onto the first decade of their offspring’s life to estimate the timing, duration and severity of exposure to their illness. The duration of parental BD was associated with a 2 to 2.5 fold increased risk of any psychopathology (HR: 1.9, 95%CI: 1.0-4.0), and unipolar depression (HR: 2.6, 95%CI: 0.9-7.5), and a 7 fold increased risk of substance use disorders (HR: 7.1, 95%CI: 1.8-37.0). A longer duration of exposure to parental BD may be an important indicator of mood and non-mood psychopathology risk in offspring. This has implications for early intervention and preventive efforts in high-risk youth.