Maternal effects can be key determinants of female fitness through their influence on early life survival. In salmonids, three main sources of mortality in early life can be attributed to redd superimposition, predation, and starvation (meditated by territory limitation). The influence of different agents of mortality will depend on maternal phenotype (e.g. body size) and within-season reproductive timing. An individual-based model, incorporating both stochastic and deterministic processes, was developed to assess how the relationships between maternal fitness, maternal phenotype (body size) and spawning timing were affected by these different sources of mortality. I found that maternal size influenced fitness under some, but not all circumstances. Larger size was beneficial when predation mortality was low, territories were limited, and/or spawner density was high. Spawning time also influenced maternal fitness; early spawned juveniles were favoured when territories were limited, whereas later spawned juveniles were favoured when predation mortality was high. Component Allee effects at low spawned densities were also detected in some simulations. These results suggest that the fitness consequences of maternal phenotype depend on the sources of mortality present. The fact that these context-dependent sources of offspring mortality in early life may vary between habitats or between years increases the difficulty in identifying the correlates of maternal fitness in salmonid fishes.

Offspring phenotype can be adaptively altered via maternal non-genetic inheritance. Such ‘maternal effects’ enable females to adjust their per offspring investment in response to variation in the offspring environment, and thus maximise their reproductive success. Consequently they play a pivotal role in population dynamics and the response of species to environmental change. Despite this, little is known about how maternal effects mediate reproductive investment in response to multiple or novel environmental changes, such as those driven by anthropogenic activity. I use the 2-spot ladybird intraguild predation system, where resources and predation risk are highly variable, to explore the role of maternal effects in the response of a native species to an invasive predator, as well as answering outstanding questions about how maternal effects function under complex and antagonistic sets of variables. The results indicate that it is unlikely that maternally mediated changes in egg phenotype will improve the survival of 2-spot ladybird offspring in the face of predation from larvae of the invasive harlequin ladybird. They do, however, demonstrate the importance of studying maternal effects in the context of the multiple environmental factors, which more accurately represent the complex environments in which organisms live and evolve, corroborating recent theoretical predictions. Finally I provide evidence of the multifaceted nature of parental effects in aposematic species and reveal the role that they may play in shaping the variation in defence and warning coloration observed in adult populations.

The early developmental environment has a profound influence on an individual's life history trajectory and parents have tremendous influence over this environment. Despite the wealth of research demonstrating that incubation temperature affects a suite of traits important to fitness in reptiles, we are only now discovering that nest temperatures are a defining component of the avian developmental environment. Aspects of the nest environment may be an important and overlooked maternal effect in birds as nearly all birds physically incubate their eggs, thus providing a clear link between parental behavior and the developmental environment of the avian embryo. My research used an interdisciplinary approach, uniting concepts from life history theory, bioenergetics. immunology, and physiological ecology to investigate the importance of incubation temperature to avian phenotype. I found that incubation temperature affects a suite of traits important for future development, survival and reproduction in a species of birds. Using a population of wood ducks (Aix sponsa) that has been the subject of long term studies I investigated the effects of incubation temperature on embryonic developmental patterns and energy expenditure, and body size and condition, stress endocrinology, thermoregulatory performance, and immunocompetence in hatchling wood ducks. In all experiments freshly laid wood duck eggs were collected from nest boxes located in SC, transported to Virginia Tech and incubated at one of three temperatures (35.0, 35.9, 37.0Ë C) that fell within the range of naturally-incubated wood duck nest temperatures. I found that less than 1Ë C differences in incubation temperature affected duckling growth and body condition, stress endocrinology, immune responses, and energy expended to thermoregulate. Many of these effects persisted days to weeks after hatching. In most cases, ducklings that hatched from eggs incubated at lowest temperature performed poorer than ducklings that hatched from eggs incubated at the higher temperatures. Incubation temperature also affected wood duck embryonic developmental trajectories and energy expended during incubation with embryos from the low incubation temperature expended more energy and developing slower than ducklings incubated at the higher temperatures. Embryonic energy expenditure could contribute to effects observed on hatchling phenotype. Because I demonstrate that incubation temperature affects hatchling phenotypic quality, the variability upon which natural selection acts, my findings have implications for avian ecology, life history evolution and conservation. / Ph. D.

Maternal effects are important mechanisms by which mothers’ may influence the phenotype of their offspring. Females may vary in the resources they can provide during offspring development and understanding the factors responsible for this variation is key to understanding offspring success- in early life as well as later life. Differential allocation has been reported to occur, however how it impacts on offspring and mother’s future reproduction still remains unclear. This is also true for maternal transferred substances like maternally transferred immunity. Contributions to date have been limited to snapshots in time, mean level of transfer and/or limited information regarding other maternal traits. For my thesis, I aim to further the understanding of maternal allocation effects and explore the transfer of maternal antibodies over an immune response of a mother, across multiple breeding attempts and accounting for embryo, maternal and paternal traits. Furthermore, I determine the effect of key male traits on general egg traits along with maternal antibodies. I examine this at the individual level using Chinese painted quail (Coturnix chinensis) who are prolific layers and sexually dimorphic. To date the majority of differential allocation studies have not necessarily addressed the assumptions of differential allocation theory. In Chapter 2 of this thesis I attempt to address some of these assumptions and explore the impact of male characteristics across a number of clutches and find separate effects of initial pairing and subsequent pairings. I found that mothers can create, by differential allocation, clutches of varying size but egg components (egg mass) appears to be largely influenced by initial clutch pairing and not by paternal traits. Furthermore, the effect on egg mass appears to be a secondary effect mediated by females adjusting their condition based on their initial pairing. I demonstrate that unlike general clutch traits (clutch size, egg mass) maternal antibodies are not affected by male characteristics (Chapter 3) carry-over effects of egg size means antibody levels may be influenced throughout life by early experiences. However, maternal immune response may be detrimentally linked to viability of offspring. Whereas maternally transferred antibodies appear to have no relationship with maternal or paternal traits, oocyte yolk antibodies during development were found to correlate with female antibodies up to 48hr prior to lay. In Chapter 4, I examine a neglected area regarding maternal effect- exploring variation between female in their transfer of antibodies. Individual females were highly consistent in the relative level of specific blood antibodies transferred to eggs across different phases of their immune response, across challenge types (bacterial and viral) and that some females consistently transfer significantly more than others. The relative level of circulating antibody transferred was independent of the individual’s overall strength of antibody response and related to the female’s body condition (while the individual’s own antibody responses were not). We found no evidence for any trade-offs between the amount transferred and overall reproductive investment in this chapter. In Chapter 5, I discuss the wider implications of my findings and suggest future research directions.

This thesis focuses on the classic problem of investment per offspring. It is an attempt to (i) reconcile theoretical research with empirical methods that can be used to test theory, (ii) test a fundamental prediction that arises from classic theory, and (iii) test one of the more recent theoretical developments. We use Atlantic salmon (Salmo salar) as a model organism. Drawing from the classic Smith–Fretwell model, we provide defensible definitions of offspring fitness that can be used in empirical studies, and we show using simulation that the Weibull-1 statistical model provides the best estimates of optimal investment patterns. Next, we apply these methods to mark-recapture data collected for juvenile Atlantic salmon. This experiment supports the prediction that parental reproductive success is maximized by increasing investment per offspring when environmental conditions become unfavourable. Having verified this prediction, we test a general extension of classic theory which broadly suggests that large-bodied females decrease the quality of the offspring environment, such that larger females in a population ought to invest relatively heavily in investment per offspring. This might occur, for example, when larger females have a greater fecundity and if optimal investment per offspring increases with sibling competition among non-dispersive offspring. The results of this experiment generally do not support the idea that large females decrease the quality of the offspring environment in Atlantic salmon. Finally, we also provide evidence against a verbal hypothesis that attempts to explain inter-population variation in egg size of salmonids as an adaptation to population-specific spawning substrates. We conclude that the classic model of egg-size optimization can be a useful tool for understanding patterns of reproductive allocation in nature, but that investment per offspring is an extremely complex trait that cannot be fully understood by invoking a simple optimality model. Variation in investment per offspring, especially that which occurs within populations, is most parsimoniously attributed to the physiological factors (e.g., variation in testosterone levels), morphological constraints (e.g., the size of the pelvic aperture) and genetic factors (e.g., genetic correlations arising from pleiotropic genes) that affect this phenotype and that constrain adaptive evolution of this trait.

All animals interact in some way with microbes during their growth and development. These interactions often prove harmful as animals find themselves exposed to pathogens or the harmful by-products of microbial growth. For many animals avoidance of microbes is difficult or impossible, particularly for species that obligately utilise microbe-laden resources during reproduction. Larvae of the carrion beetle Nicrophorus vespilloides are significantly harmed by the bacteria they encounter during their development on decomposing vertebrate carcasses. However, these effects can be partially ameliorated by parental investment into behaviours which reduce the effects of microbial exposure. In this thesis I focus on two aspects of N. vespilloides response to microbial competition. First I investigate the composition and fitness effects of the application of exogenous secretions by parents and larvae to their breeding resource. This behaviour in parents has long been hypothesized to form an important part of the antimicrobial component of parental care, but this has not been rigorously tested. Nor, prior to my work, has any experimental attention been given to the possibility that larvae also contribute to antimicrobial production while on the carcass. Second I investigate the late-life and intergeneration effects of microbial exposure during development on a range of beetle life history traits including larval body size, brood size and immune function and survival in response to bacterial challenge. My results demonstrate the following: i) that larval N. vespilloides suffer significant harm from microbial competition during development that manifests itself in several ways, e.g. reduced body size, increased susceptibility to infection, or reduced ability of mothers to provide post hatch maternal care; ii) that the effects of microbial competition can be mitigated by parental behaviours that reduce the level of microbial contamination on a resource. Specifically, mothers apply antimicrobial secretions containing lysozyme to the carcass which kills bacteria and significantly increases larval survival; iii) that larvae are not totally reliant on their parents for antimicrobial protection because they too can secrete exogenous antimicrobial compounds similar in activity to their parents and which significantly increase larval fitness; iv) the effects of microbial competition can result in transgenerational effects that reduce offspring fitness but which can also provide context-dependent benefits by increasing larval survival when post-hatch parental care is poor and following challenge with pathogenic infection. By developing on and consuming carrion Nicrophorus larvae and other specialist scavengers experience an extreme example of the challenges faced by opportunistic carrion users or animals that for any reason utilise microbially contaminated resources. This makes them ideal model organisms to study adaptations to the presence of complex microbial communities that may contain both pathogens and toxin producers.

Population dynamics of large ungulates are complex and vary with fluctuations in factors such as predation, resource availability, human disturbance, and weather (Gaillard et al. 1998, Forrester and Wittmer 2013). These regulating factors exhibit similar effects on ungulate populations by changing vital rates such as birthrate, death rate, emigration or immigration (Gaillard et al. 2000). To better understand the mechanisms influencing population change, it is useful to involve tools from multiple disciplines (Krausman et al. 2013). Here we explore population dynamics of mule deer (Odocoileus hemionus) through the lenses of two distinct fields: population ecology and genomics. In the first chapter we examine the influence of maternal effects on offspring fitness. In the second chapter we present a high-quality, chromosome-level reference genome for mule deer. We expect results from each of these studies to provide valuable resources for continued research and conservation of mule deer.

No description available.

I investigated the maternal effects that take place in a joint-nesting bird: the smooth-billed ani. Female anis were shown to respond to increasing group size by increasing the number of eggs produced per capita, by tossing and burying more eggs per capita, and by taking longer to reach the dedicated incubation phase. These results support the hypothesis that females respond to increased egg laying competition by trying to skew the contents of the final incubated clutch of eggs in their own favor. I showed that in ani groups, yolk testosterone and estradiol deposited by females in eggs increased from early- to late-laid eggs. Increases in yolk steroid levels over the laying sequence may function to mitigate the disadvantage of being a later-hatched chick. This maternal influence may not be a mere reflection of a female's hormonal status as female plasma circulating levels of testosterone and estradiol did not vary in the same direction as yolk hormone profiles. I showed that yolk corticosterone levels, an indicator of maternal physiological stress, increased with laying order in multi-female groups, but not in single-female groups. Results suggest that laying females experience higher levels of stress in multifemale groups. The above results suggest that communal life in anis generates competition and egg production waste that likely reduces short-term per capita reproductive benefits. Female anis can vary egg quality via deposition of hormones in eggs, and also lay eggs of different sizes. I showed that circulating plasma testosterone levels were higher in nestlings with better begging abilities. Furthermore, nestlings hatched from eggs laid late in the laying sequence had better begging abilities. These results suggest that testosterone is an important controlling mechanism of begging behaviour, and that female testosterone depositions in eggs rave long lasting effects on offspring development and behavior. / Thesis / Doctor of Philosophy (PhD)

Investment in reproduction is considered to be crucial component of life history traits. Reproductive success is however constrained by generally unpredictable environmental conditions. Based on "bet hedging" theory, individuals are forced to eliminate such unpredictability via the mixed strategy to maximize their long-term fitness. Predation represents underlying factor affecting individual reproductive success, and it undoubtedly lies behind the evolution of alternative reproductive strategies such as extra-pair paternity and conspecific brood parasitism. Behavioral mechanisms related to nest defense are thought to be investment in reproduction in accordance with trade-off between actual and residual reproductive value. Despite the extensive interest in the principles associated with parental investment into the nest defense, studies describing in detail the pattern of particular antipredator strategies are rare. Similarly, mechanisms responsible for maintenance of egg- viability during prolonged egg-laying period in species delayed the onset of incubation are poorly understood. In accordance with mentioned themes, this thesis includes publications aimed at aspects of reproductive biology and antipredator behavior in Mallards (Anas platyrhynchos). Particular publications concretely documented: a)...