The brown trout, Salmo trutta L., displays one of the most variable and polymorphic life-history strategies of all the salmonids. In some populations, individuals spend their whole life-cycle in the river (freshwater-resident) whereas in others, a varying proportion migrates to sea for variable amounts of time to better feeding conditions before returning to spawn (anadromous). The ‘decision’ if an individual will migrate or not will be determined by the balance of the costs and benefits of following a particular life-history strategy. The balance of these, which do not affect males and females equally, will determine the future success (measured by fitness) of each strategy. This research addresses the influences of parental contribution, mainly maternal effect, of anadromous and freshwater-resident brown trout on offspring performance and subsequent life-history. A partial migratory population of brown trout was studied in the Tadnoll Brook, one of the seven major tributaries on the River Frome. The tributary is classified as a circum-neutral chalk stream, 9.9 km long with a catchment approximately 50 km2. Carbon and nitrogen stable isotope analysis (SIA) was used to quantify maternal reproductive contribution of anadromous and freshwater-resident brown trout to offspring and determine the future success (measured by fitness) in terms of size and time of emergence. A panel of 12 microsatellite loci was used to assign parentage to 0+ parr. Using field data collected over 1.5 years on individual fish, this study tested parental influence on offspring performance in terms of size and growth rate and calculate the reproductive contribution of maternal/paternal anadromous and freshwater-residents. Adult life-history strategy was identified using a combination of results from SIA, PIT tag data and ecological data (body size, temperature). Parr life-history strategy (1+) was inferred using PIT tag detection data. The results of the SIA indicated fry of anadromous females emerged earlier and at a larger size than fry of freshwater-resident females. Parentage assignment of parr was low (28 %), with 8 parr assigned to both parents and 43 assigned to only a single parent. There was no detectable effect of parental life-history on parr size and growth rate, however the raw data may suggest offspring of anadromous parents have an early size advantage but a slower growth compared to offspring of freshwater-resident parents during the first year of the parr stage. Twenty-four percent of the offspring were identified as putative smolts at 2+ and both forms interbred and could produce offspring of each life-history. Estimates of reproductive contribution (SIA and growth) show a higher proportion of anadromous females and males (growth only) contributed to offspring production. The results of this research indicate that the maternal anadromous contribution is higher in the Tadnoll Brook population, affording fitness benefits to their offspring during early ontogeny such as size advantages and emerging at a more profitable time to establish feeding territories. Adult life-history does not appear to influence juvenile (0+ parr) life-history but may have an effect on offspring performance. The presence of both forms in the population suggests the anadromous fitness benefits to offspring may only have an affect during ontogeny and early stages of growth. Then after juveniles reach a size threshold environmental factors influence offspring life-history, resulting in the largest parr with the fastest growth adopting an anadromous life-history.

Oxidative stress has recently been highlighted as a potential physiological mechanism underpinning life-history trade-offs in animals. While the role of oxidative stress in mediating such trade-offs is receiving increasing attention, its importance in wild populations remains poorly understood. In this thesis, I use a wild population of cooperatively breeding white-browed sparrow weavers (Plocepasser mahali) to investigate the role that oxidative stress plays in mediating the costs of reproduction and immune defence. Cooperative animal societies offer a unique opportunity to investigate the costs of reproduction, because dominants frequently monopolise breeding opportunities (exhibiting higher reproductive effort than subordinates), and subordinate cooperative contributions frequently lighten reproductive workloads. My findings reveal, first, that dominants’ reproductive monopolies do not arise because they exhibit superior oxidative balance, as no such rank-related differences in oxidative state exist prior to breeding (Chapter 2). However, the higher reproductive effort of dominant females may underpin their differential declines in antioxidant protection after the breeding season (Chapter 2). Second, experimental manipulation of reproductive effort reveals marked oxidative damage and body mass costs incurred during reproduction. However, these costs are entirely mitigated in large social groups, suggesting that the cooperative contributions of helpers may offset the costs of reproduction for all group members (Chapter 3). While this represents rare evidence of an oxidative stress cost of reproduction in the wild, longitudinal data suggests that these costs do not endure after the breeding season (Chapter 4), highlighting that circulating markers of oxidative balance are unlikely to mediate long-term costs of reproduction. Finally, an immune activation experiment reveals that, while mounting an immune response causes no net change in oxidative balance, the scale of the response can be adjusted according to baseline antioxidant protection in an oxidative-condition-dependent manner (Chapter 5). Together my results provide support for the role of oxidative stress in shaping life histories in the wild. Furthermore, evidence of rank-related disparities in oxidative balance and the avoidance of reproductive costs in large social groups may have important implications for our understanding of both the evolution of cooperative breeding and the patterns of health and ageing in societies.

A study of the life history and secondary production of Caenis latipennis, a caenid mayfly, was conducted on Honey Creek, OK. from August 1999 through September 2000. The first instar nymph was described. Nymphs were separated into five development classes. Laboratory egg and nymph development rates, emergence, fecundity, voltinism, and secondary production were analyzed. C. latipennis eggs and nymphs take 132 and 1709 degree days to develop. C. latipennis had an extended emergence with five peaks. Females emerged, molted, mated, and oviposited in an estimated 37 minutes. Mean fecundity was 888.4 ± 291.9 eggs per individual (range 239 -1576). C. latipennis exhibited a multivoltine life cycle with four overlapping generations. Secondary production was 6,052.57 mg/m2/yr.

<p>The evolution of reproductive strategies involves a complex calculus of costs and benefits to both parents and offspring. Many marine animals produce embryos packaged in tough egg capsules or gelatinous egg masses attached to benthic surfaces. While these egg structures can protect against environmental stresses, the packaging is energetically costly for parents to produce. In this series of studies, I examined a variety of ecological factors affecting the evolution of benthic development as a life history strategy. I used marine gastropods as my model system because they are incredibly diverse and abundant worldwide, and they exhibit a variety of reproductive and developmental strategies. </p><p>The first study examines predation on benthic egg masses. I investigated: 1) behavioral mechanisms of predation when embryos are targeted (rather than the whole egg mass); 2) the specific role of gelatinous matrix in predation. I hypothesized that gelatinous matrix does not facilitate predation. One study system was the sea slug Olea hansineensis, an obligate egg mass predator, feeding on the sea slug Haminoea vesicula. Olea fed intensely and efficiently on individual Haminoea embryos inside egg masses but showed no response to live embryos removed from gel, suggesting that gelatinous matrix enables predation. This may be due to mechanical support of the feeding predator by the matrix. However, Haminoea egg masses outnumber Olea by two orders of magnitude in the field, and each egg mass can contain many tens of thousands of embryos, so predation pressure on individuals is likely not strong. The second system involved the snail Nassarius vibex, a non-obligate egg mass predator, feeding on the polychaete worm Clymenella mucosa. Gel neither inhibits nor promotes embryo predation for Nassarius, but because it cannot target individual embryos inside an egg mass, its feeding is slow and inefficient, and feeding rates in the field are quite low. However, snails that compete with Nassarius for scavenged food have not been seen to eat egg masses in the field, leaving Nassarius free to exploit the resource. Overall, egg mass predation in these two systems likely benefits the predators much more than it negatively affects the prey. Thus, selection for environmentally protective aspects of egg mass production may be much stronger than selection for defense against predation. </p><p>In the second study, I examined desiccation resistance in intertidal egg masses made by Haminoea vesicula, which preferentially attaches its flat, ribbon-shaped egg masses to submerged substrata. Egg masses occasionally detach and become stranded on exposed sand at low tide. Unlike adults, the encased embryos cannot avoid desiccation by selectively moving about the habitat, and the egg mass shape has high surface-area-to-volume ratio that should make it prone to drying out. Thus, I hypothesized that the embryos would not survive stranding. I tested this by deploying individual egg masses of two age classes on exposed sand bars for the duration of low tide. After rehydration, embryos midway through development showed higher rates of survival than newly-laid embryos, though for both stages survival rates over 25% were frequently observed. Laboratory desiccation trials showed that >75% survival is possible in an egg mass that has lost 65% of its water weight, and some survival (<25%) was observed even after 83% water weight lost. Although many surviving embryos in both experiments showed damage, these data demonstrate that egg mass stranding is not necessarily fatal to embryos. They may be able to survive a far greater range of conditions than they normally encounter, compensating for their lack of ability to move. Also, desiccation tolerance of embryos may reduce pressure on parents to find optimal laying substrata. </p><p>The third study takes a big-picture approach to investigating the evolution of different developmental strategies in cone snails, the largest genus of marine invertebrates. Cone snail species hatch out of their capsules as either swimming larvae or non-dispersing forms, and their developmental mode has direct consequences for biogeographic patterns. Variability in life history strategies among taxa may be influenced by biological, environmental, or phylogenetic factors, or a combination of these. While most prior research has examined these factors singularly, my aim was to investigate the effects of a host of intrinsic, extrinsic, and historical factors on two fundamental aspects of life history: egg size and egg number. I used phylogenetic generalized least-squares regression models to examine relationships between these two egg traits and a variety of hypothesized intrinsic and extrinsic variables. Adult shell morphology and spatial variability in productivity and salinity across a species geographic range had the strongest effects on egg diameter and number of eggs per capsule. Phylogeny had no significant influence. Developmental mode in Conus appears to be influenced mostly by species-level adaptations and niche specificity rather than phylogenetic conservatism. Patterns of egg size and egg number appear to reflect energetic tradeoffs with body size and specific morphologies as well as adaptations to variable environments. Overall, this series of studies highlights the importance of organism-scale biotic and abiotic interactions in evolutionary patterns.</p> / Dissertation

Organisms capable of self-fertilization typically exhibit two evolutionary syndromes uniting high inbreeding depression with low levels of selfing, or low inbreeding depression and high levels of selfing. This study tests for inbreeding depression in an apparent self-compatible, hermaphroditic marine nemertean worm, Prosorhochmus americanus. Fecundity and timing to first reproduction were assessed in isolated and paired worms. Isolated worms produced significantly more offspring than paired worms and did not show inbreeding avoidance. The selfing rate of natural populations was evaluated using species-specific microsatellites and is consistent with preferential selfing (mean: 0.801), though some outcrossing appears to take place. Population genetic structure indicates populations are disjunct and characterized by low levels of gene flow. Our results reveal P. americanus exhibits an interesting suite of life-history traits, uniting high dispersal potential through self-fertilization and high fecundity, with the lack of a dispersive larval stage and low levels of gene flow.

Parental care is likely to evolve when benefits of care are greater than costs. Provision of parental care may buffer vulnerable offspring against unpredictable or hazardous environments permitting parents to breed in situations too hostile for unassisted juvenile survival. The nature of environmental unpredictability faced by parents and their offspring (e.g., availability of nutritional resources, breeding resources and/or the strength of competition) provides the ecological context in which costs and benefits of parental traits are defined. Therefore investigations about how the environment might shape parental traits ought not only to be conducted in the laboratory but also in a natural setting where unanticipated parameters may have profound effects on theoretical predictions. I conducted a series of manipulative experiments and observational studies in the laboratory and in the field using burying beetles, Nicrophorus vespilloides, to examine the effects of environmental variation on parental competitive ability, reproductive productivity, longevity and the expression of parental sex-role differences and alternative reproductive tactics. In these beetles a relative size advantage confers success in contests for scarce and vital breeding resources so a central prediction was that reproductive success would be positively correlated with body size. In contrast I found that reproductive performance was favoured over contest success when nutritional resources were delayed temporarily during a developmental window. Larger beetles do win contests for breeding-resources but the benefits of being large depend on the quality of the social environment experienced (i.e., the relative size of an opponent). In a naturalistic setting, smaller males avoided direct contests because they attracted proportionately more females and as a result their breeding associations were more often monogamous. This has potential benefits for females because they avoid female-female contests and brood parasitism. Variation in the nutritional environment provided by parents (the carcass size on which offspring are reared) directly influences body size creating a dynamism between the nutritional and social environments experienced by these beetles depending on their size, which has ramifications for their individual success and maintenance of alternative strategies in the population as a whole.

The squamata reptiles present a wide array of reproductive strategies. In the genus Lepidophyma from the neotropical family Xantusiidae, there are 19 species, all of them live- bearing and diploid. Obligatory unisexuality is also present in some species. This obligatory unisexuality did not evolve via hybridization, which is unique among vertebrates. The genus thus presents a very interesting, but still poorly little explored group. Only recently our team has discovered a facultative unisexuality in Lepidophyma smithii. The unisexually produced offsprings are not fully homozygous are of both sexes, which is unique for vertebrates as well. The aim of my work is to describe the basic reproductive biology of this species, e.g. the relationship between female size and clutch size and offspring size. Additionally, my work focuses on sexual dimorphism. I tested whether L. smithii is dimorphic in body length and head size. These traits are often sexually dimorphic in squamatesu. Also, I documented the ontogeny of sexual dimorphism and reconstructed growth curves for males and females.

Saxicolous lichens on exposed bedrock are subjected to desiccation stress and intense light levels. Members of the genera Xanthoparmelia and Arctoparmelia are common foliose lichens on the Precambrian Shield, produce abundant sexual structures, and form part of the bedrock communities. The general goal of this thesis was to better understand the influence of community and underlying geology on three saxicolous lichens: Arctoparmelia centrifuga, Xanthoparmelia viriduloumbrina and X. cumberlandia. More specific goals were further examined in five chapters to investigate: 1) life history strategies of the three species, 2) a trade-off between fecundity and fungal secondary metabolite production; 3) an effect of substratum element composition on previously defined communities and lichen biology, 4) substratum preferences of Xanthoparmelia species, and 5) the photobiont guild hypothesis of the three species in a preliminary study. Field collections of lichens and environmental data were made in four locations on the Precambrian Shield in Manitoba and Ontario. Secondary metabolites were determined by digitally enhanced thin-layer chromatography. Fecundity was measured by number of apothecia, ascospores, and percent germination. Elements in rock samples were quantified by aqua-regia digest and inductively coupled plasma optical emission spectroscopy analysis and light microscopy was used to observe and quantify fungal germination and growth. The results showed eighty-one lichen species comprising three lichen communities; mossy rock, grassy rock, and treed rock communities. Lichen communities and fecundity were used to characterize life history strategies as competitive for Arctoparmelia centrifuga, stress tolerant for Xanthoparmelia viriduloumbrina, and ruderal generalist for Xanthoparmelia cumberlandia. A potential trade-off was reported for X. cumberlandia between sexual fecundity and a secondary metabolite. Substratum preferences were found at the genus level and element differences at the species level. Experimental evidence further supported geological preferences for the three species. Finally, the photobiont guild hypothesis could not be supported by this preliminary work. This research provides a broad overview of ecological and biological patterns found in Arctoparmelia and Xanthoparmelia species. The research forms a foundation for further studies in substratum preference and life history characterization in lichens. It can be further applied to habitat suitability modelling which may be valuable for phylogenetic context or in conservation biology of lichens. / October 2015

Atlantic salmon Salmo salar has a complex life cycle, including long migrations and habitat shifts for both juveniles and adults. As such, salmon populations are vulnerable to habitat degradation and fragmentation along their migratory routes. This makes management and conservation a complex task requiring knowledge of salmon ecology at different temporal and spatial scales. In this thesis I highlight the use of a holistic life-history based approach in the conservation and management of wild and hatchery-reared salmon in regulated rivers and lakes. Small populations of wild-reproducing landlocked salmon and trout Salmo trutta exist in the regulated River Klarälven, Sweden. Since the 1930s, transportation of adult spawners upstream of eight dams has given the fish access to spawning grounds. The number of returning wild spawners became critically low in the 1960s, but stocking of hatchery smolts resulted in an increase in spawners that continues today. My data show that wild smolt may suffer high mortality due to multiple dam passages. To ensure viable populations of wild populations, future management should include both up- and downstream solutions that ensure connectivity in the system. The recreational and commercial salmonid fishery are maintained by compensatory stockings, yielding annual catches of about 75 tons, and a river return rate of hatchery fish of about 1%. As a large portion of the stocked smolts does not survive downstream migration to the lake, there has been discussion about the quality of the stocked smolt and about stocking strategies. Based on my studies, producing hatchery smolts more closely resembling wild-born conspecifics should result in reduced loss rates. I suggest changes in the hatchery and stocking procedures to increase the survival of stocked smolts. The results of my research should be applicable to other regulated systems, particularly those with mixed stocks of wild and hatchery salmonid populations. / Atlantic salmon Salmo salar has a complex life cycle, including long migrations and habitat shifts for both juveniles and adults. As such, salmon populations are vulnerable to habitat degradation and fragmentation along their migratory routes, which make management and conservation a complex task requiring knowledge of salmon ecology at different temporal and spatial scales. In this thesis, I highlight the use of a holistic approach in the conservation and management of wild and hatchery-reared salmon in regulated rivers and lakes. Small populations of wild-reproducing landlocked salmon and trout Salmo trutta exist in the regulated River Klarälven, Sweden. Since 1930, transportation of adult spawners upstream of eight dams has been done to give the fish access to the spawning grounds. My data indicate that a large proportion of the wild smolts are lost due to multiple dam passages, and future management should include both up- and downstream solutions, ensuring connectivity in the system. The fishery in Klarälven and Lake Vänern is maintained by compensatory stockings, yielding catches of about 75 metric tons and a river return rate of stocked fish of about 1%. I suggest changes in the hatchery and stocking procedures to increase the survival of stocked smolts.

The author joins the Peace Corps in the hopes that he will discover who he really is yet he only finds frustration. Upon returning to the States he has a daughter and finds peace. Within this peace, as he types up the life history of a friend, he finally makes a breakthrough, yet the answer he finds is not to his liking.