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Morphological, biochemical and minisatellite DNA variation was investigated at the colour ringed Brackenhurst House Sparrow population. Measurements and blood samples were collected from 584 nestlings and 692 other birds between 1985 and 1989. Six loci (6PGD, IDH, PEPD2, PEPD3, PEPT and transferrin) which had been the subject of a previous report (Burke, 1984) were investigated by starch gel electrophoresis. All followed Mendelian inheritance patterns, were in Hardy Weinberg equilibria and displayed temporal stability in allele frequencies. No evidence was found of the previously reported segregation distortion at PEPD3 and transferrin but artefact bands were encountered when scoring the latter. Family groups identified by observing colour ringed adults during feeding visits were examined using both enzyme and minisatellite DNA markers. Z chromosome linkage of several fingerprint bands was implicated, though most segregate independently. The probability of detecting an extra-pair fertilization was estimated as 0.5454 using starch gels and 0.9998 by fingerprinting. 51 out of 420 nestlings from 144 broods possessed several bands absent from the attendants' fingerprints. All nestlings with multiple mismatches shared many bands with the attendant female but a number consistent with band sharing between unrelateds with the male, i.e. nonparentage, was the result of cuckoldry. 24% of broods and 37% of males were affected. A correlation between the presence of extra-pair offspring and poor hatching success was noted. Cuckoldry was twice as successful in broods which contained infertile eggs. Metric variation was examined in the confirmed families. Significant heritabilities were demonstrated for weight, tarsus and tail length but environmentally induced variance was considerable. Yearlings were smaller than full adults in plumage length. This may be due to levels of protein reserves at critical growth periods. Some evidence of assortative mating for tail length was found which was unrelated to age associated changes.

Genetic variation in natural populations of four species of swans (Cygnus bewickii, Cygnus olor, Cygnus buccinator and Cygnus cygnus) has been investigated by examining minisatellite loci using human DNA fingerprinting probes pSPT19.6 and pSPT18.15. It has been found that swan minisatellites are highly variable. However, the degree of variation depends on the population structure and species. Bewick's Swans at Slimbridge have the highest degree of minisatellite variation, Whooper Swans at Caerlaverock come second, and then Mute Swans, and Trumpeter Swans in Montana. Comparative study of DNA fingerprints among populations and among species suggested that swan minisatellites are subject to specific as well as population differentiation, although the function of minisatellites remains an unsolved mystery. Hypervariable minisatellites of swans that are detected by DNA fingerprinting are stably inherited as codominant markers. DNA fingerprinting has been used to study mating behaviour of Mute and Whooper Swans in the wild The results showed that the Whooper swans were almost strictly monogamous and Mute Swans exhibited an adaptable reproductive system. A genomic library from Cygnus olor was constructed and dozens of minisatellites were isolated. Most of the cloned swan minisatellites were variable, some showed specific variation, and one (pcoMS6.1) detected RFLPs in PstI digests of Trumpeter Swans.

A main challenge in evolutionary ecology is to elaborate the main ecological factors that vary in a study system and analyse how those factors shape the phenotype of organisms in their natural environment. These ecological variables can have complex effects since most life history traits are correlated. Here I examined the effects of ecological factors on life history traits, and the relationship among life history traits of North Uist three-spined stickleback, Gasterosteus aculeatus (hereafter stickleback). Both abiotic and biotic factors that are commonly measured in aquatic systems, and are known to vary greatly between North Uist lochs, were examined. The traits analysed were body size, age and size at maturation, proportion of fish over one year old, and the fecundity rate. My results showed that there was strong variation in water chemistry and inter-specific competition among the lochs on North Uist. Lochs on the west side of the island were characterised by higher sodium and calcium ion concentrations, higher pH and conductivity, and increased inter-specific competition. As a result, western populations had a faster absolute growth rate, larger body size, and a higher proportion of older fish, indicative of a longer life span. Although western populations had a larger body size, they tended to mature later with a smaller gonadosomatic index. They also favoured a larger number of eggs, but with a smaller egg size. Variations within population showed that larger females had greater fecundity but small egg size. Both plasticity and evolution appear to have contributed to these life history variations. Overall, variation in life history of North Uist stickleback was largely related to measures of resources availability and interspecific competition, except for egg size which was mostly associated with variation in predator density.

The processes driving and maintaining variable immune responses are poorly understood compared with other aspects of an organism’s ecology. This is particularly true from an evolutionary perspective, as the evolutionary relationships between immune responses and other traits and processes in nature remain inadequately explored. I investigated these associations in this thesis using the three-spined stickleback system as an evolutionary and immunological model. I combined sampling of wild individuals with genomic analyses to demonstrate phenotypic and genomic associations between immune responses and life history evolution across multiple populations. I also observe how experimental changes in daylength, a seasonal cue, modulate immune responses and increase parasite susceptibility in a controlled laboratory experiment. These findings occur independently of natural variation in parasite resistance. Stickleback are also a model for studies of speciation. I used sampling of wild hybrids to assess the significance of immune variation in postzygotic isolating mechanisms between diverging ecotypes; although my findings suggest a minor role. Finally, I demonstrate that genomic responses to parasitism and abiotic environmental variation are repeatable across independent, intercontinental adaptive radiation events in sticklebacks; conferring a repeatability of the evolutionary relationships of immune variation documented in this thesis. The findings within this thesis therefore provide novel insights into poorly explored or open areas of research regarding how variable immune responses evolve in nature.

Understanding the natural behaviour and coexistence of species is important for the conservation of intact ecosystems, and behavioural studies can enhance our knowledge of processes such as communication and competition. I investigated the social dynamics and scent-marking behaviour of spotted hyaenas (Crocuta crocuta), and the occurrence of interspecific olfactory eavesdropping among African mammals, within the Okavango Delta ecosystem of Botswana. First, social network analysis found that the hyaena population was comprised of five main clans that maintained territories but whose home ranges overlapped considerably. Scavenging at large carcasses involved associations between individuals from different clans and resulted in relative tolerance toward territorial intruders. Second, observations of communal latrine use found that latrines are likely involved in territorial advertisement by hyaena clans, and cyclical patterns of latrine growth and decline were linked to annual rainfall. Third, a translocation experiment showed that hyaena scats appear to be less important for hyaena communication than other cues associated with latrines, especially as hyaenas did not differ in their behaviour towards scat originating from latrines located in resident versus non-resident clan home ranges. Heterospecific mammals investigated, scent-marked, and were vigilant at hyaena latrines, suggesting a potential function for hyaena latrines in interspecific eavesdropping and/or communication. Fourth, a urine presentation experiment found that the investigation of sympatric predator urine by African mammals stimulated vigilance behaviour, suggesting that olfactory signals provide information about predation risk. Hyaenas exhibited context-specific differences in behaviour towards predator urine: they were more likely to investigate urine samples alongside indicators of predator activity (i.e. carrion odour, carcasses) and were most likely to exhibit vigilance at carcasses when exposed to urine from lions and wild dogs. This study greatly enhanced our understanding of spotted hyaena behaviour within the Okavango Delta, an important ecosystem for the conservation of African large predators. Furthermore, this study provided the first experimental evidence of the role of hyaena scats in intraspecific communication and interspecific olfactory eavesdropping at latrines. My research findings regarding the population’s clan structure and home ranges will form the foundation for subsequent investigation into human-wildlife conflict in the study area. Furthermore, the results from two scent experiments shed light on the potential importance of olfactory signals for mediating interspecific interactions among African mammals, particularly among large predators.

This thesis investigates the demographics of paleo-populations of white-tailed deer (Odocoileus virginianus) as a means of testing the hypothesis that this species was domesticated or managed as a vital cultural and economic resource by the ancient Maya in Mesoamerica. To do so it employs a set of standardized bone measurements derived from a modern population and compares them with 1100 deer bone samples recovered by archaeologists from Maya sites dating from 450 B.C. to the late 16th century. These measurements were also applied to modern white-tailed deer specimens representing a discrete population from south eastern Florida of know age, and sex, for use as a baseline. The recorded measurements were used for side by side comparisons and to generate log ratios testing population stature and sexual dimorphism represented in the archaeological materials. Changes in deer stature and mortality profile over time are examined and tested against standard methods for the detection of herd management strategies, that may potentially reveal deer domestication or resource management. Pathologies common to white-tailed deer are identified and their potential for assessing the ontological age of mature deer is investigated. The results show variations in white-tailed deer stature over time and space, suggesting dynamic alterations in prey selection that may be reflective of changes in Maya social complexity.

Electrical stimulation of the heel or toes evokes short latency polysynaptic reflexes in muscles of the ankle extensor medial gastrocnemius (MG), the ankle flexor tibialis anterior (TA) and the knee flexor biceps femoris (BF), the co-ordinated actions of which form an organized protective withdrawal response. Previous studies in the rabbit have shown that such reflexes are enhanced (sensitized) or inhibited by application of the chemogenic agent mustard oil (MO) to various areas of the body surface in a manner that reinforces the protective function of these responses. The organization of these ‘sensitization fields’ was strictly controlled by supraspinal pathways from the brain. The aim of the present experiments was therefore to extend these studies of the spatial organization of sensitization of withdrawal reflexes into the rat, the species most commonly used in pain research. Patterns of facilitation and inhibition of spinal reflexes were obtained and compared in decerebrate spinalized, decerebrate non-spinal, and Alfaxan- anaesthetized rats by applying mustard oil to sixteen different body locations including sites on the ipsilateral and contralateral hindlimbs as well as other off limb areas such as the snout and tail. It was found that in decerebrate spinalized animals, MO application to ipsilateral hindlimb sites enhanced but never inhibited reflex responses in the limb, whilst MO treatment to off limb sites was without effect. In contrast in anaesthetized animals the prevalent effect of MO was inhibition from treatment sites distributed across the entire animal. Reflexes in animals with an intact spinal cord (decerebrate or anaesthetized) were facilitated or inhibited by MO application to ipsilateral hindlimb sites in a way that resembled the modular organization of reflexes per se and previous sensitization studies in the rabbit. However clear differences were also observed in the effects of MO between the two species, including modulation of the heel-MG extensor response in spinalized animals, which in rabbit was inhibited by MO application to the ipsilateral toes whereas in the rat no inhibition by MO was found in spinalized animals. Sensitization of hindlimb reflexes by MO in the rat therefore seems to be influenced by descending inhibitory and facilitatory pathways. These influences were further investigated in subsequent studies. Whilst the predominant effect of spinalization was a loss of inhibition and an expansion of sensitization fields, in the toes-evoked TA reflex the reverse was noted with regard to MO treatment of distal ipsilateral sites. In this case, facilitation found in non-spinal animals did not occur in the equivalent spinalized cohort, and thereby implies that a descending facilitatory pathway is also implicated in the control of spinal reflex excitability in this model. In decerebrate rats, the noradrenergic α2-adrenoceptor antagonist RX 821002 or the serotonergic 5-HT3 receptor antagonist ondansetron were administered directly to the spinal cord (intrathecally, i.t.) either alone (dose-response studies) or as a single dose between two successive MO applications to one of three ipsilateral skin sites on the hindlimb (heel, metatarsophalangeal joints or flexion of the ankle). Cumulative i.t. doses of RX 821002 revealed the presence of tonic descending inhibition of all reflex responses as well as preventing MO-evoked inhibition (and possibly facilitation) of reflex responses suggesting the involvement of the α2-adrenoceptor subtype in mediating these effects in this model. On the other hand, cumulative i.t. ondansetron administration resulted in a decrease in the magnitude of reflex responses, thus indicating that 5-HT3 receptors are indeed implicated in tonic descending facilitation of spinal reflexes. In addition i.t. ondansetron revealed that potentiation (and possibly inhibition) of reflexes following an acute chemogenic insult appears to involve the actions of serotonin at 5-HT3 receptors in the spinal cord. These studies therefore show that the organization of sensitization of hindlimb reflexes in the rat are modulated by supraspinal influences that exist as a balance of descending facilitatory and inhibitory pathways, mediated at least in part by serotonergic 5-HT3 receptors and noradrenergic α2-adrenoceptors.

The Notch signalling pathway is pivotal in ensuring that the processes of arterial specification, angiogenic sprouting and haematopoietic stem cell (HSC) specification are correctly carried out in the dorsal aorta (DA), a primary arterial blood vessel in developing vertebrate embryos. Using the zebrafish as a model organism, and additional experimental observations from mouse and cell line models to guide mathematical modelling, this thesis aims to better understand the mechanisms involved in the establishment of a healthy vasculature in the growing embryo. We begin by studying arterial and HSC specification in the zebrafish DA. Mathematical models are used to analyse the dose response of arterial and HSC genes to an input Notch signal. The models determine how distinct levels of Notch signalling may be required to establish arterial and HSC identity. Furthermore, we explore how Delta-Notch coupling, which generates salt-and-pepper patterns, may drive the average gene expression levels higher than their homogeneous levels. The models considered here can qualitatively reproduce experimental observations. Using laboratory experiments, I was able to isolate DA cells from transgenic zebrafish embryos and generate temporal gene expression data using qPCR. We show that it is possible to fit ODE models to such data but more reliable data and a greater number of replicates at each time point is required to make further progress. The same VEGF-Delta-Notch signalling pathway is involved in tip cell selection in angiogenic sprouting. Using an ODE model, we rigourously study the dynamics of a VEGF-Delta-Notch feedback loop which is capable of amplifying differences betwen cells to form period-2 spatial patterns of alternating tip and stalk cells. The analysis predicts that the feeback strengths of Delta ligand and VEGFR-2 production dictate the onset of patterning in the same way, irrespective of the parameter values used. This model is extended to incorporate feedback from filopodia, growing in a gradient of extracellular VEGF, which are capable of facilitating tip cell selection by amplifying the resulting patterns. Lastly, we develop a PDE model which is able to properly account for VEGF receptor distributions in the cell membrane and filopodia. Receptors can diffuse and be advected due to domain growth, defined by a constitutive law, in this model. Our analysis and simulations predict that when receptor diffusivity is large, the ODE model for filopodia growth is an excellent approximation to the PDE model, but that for smaller diffusivity, the PDE model provides valuable insight into the pattern forming potential of the system.

The biochemical genetics of two natural populations of house sparrows, Passer domesticus, at sites 20km apart in Nottinghamshire, England, were investigated. Seven polymorphic protein loci were sampled non-destructively by taking blood samples from over 1500 individually marked birds. A detailed investigation of the genetics of these loci was conducted for 124 clutches containing 357 nestlings where the parents were also sampled. Segregations at four loci (6PGD, PEPD2, PEPD3 and lDHC) agreed with a simple Mendelian model of codominant inheritance. One locus (EST2) contained null alleles. Two loci (PEPD3 and GP1) showed segregation distortion in all sex, site and year classes. This distortion was not attributable to the misinterpretation of gel patterns; possible causes involving the operation of natural selection were discussed. Linkage analyses were conducted, and no significant evidence was obtained for linkage between any combination of loci. Of the nestling genotypes, 12.9% were interpreted as being genetically incompatible with those of their parents. Exclusion probabilities were calculated as 43-51% for nonpaternity and 59-67% for nonparentage. The applicability of these estimated probabilities was tested by the random reassortment and comparison of observed parental genotypes among observed sibship genotypes. Significantly fewer nestlings were excluded in these simulations than expected from calculated exclusion probabilities, though the distribution of multiple mismatches did not differ from expectation. A deficiency of multiple mismatches was found in the field data, implying the occurrence of errors; the possible sources of error were considered. The most parsimonious interpretation of those mismatches that did not appear to be due to errors was that they resulted from a rate of nonpaternity of about 6%. No heterogeneity in the rate of mismatches was observed within or among breeding seasons or sites. Genotype and allele frequencies were presented for each locus in each age, sex and sampling year class at each study site. The samples were not found to depart from Hardy Weinberg equilibrium, and there was no evidence for significant inbreeding within sites. There were no differences in allelic distributions between the sexes or among years for adults within the populations. No differences were found among age groups or nestling year classes when allowance was made for sib correlations. Heterozygosities were higher at Brackenhurst than at Sutton Bonington for most loci, and the overall difference was significant. There was a particularly large difference in allele frequencies between nestlings in each population for GP1. Digenic gametic disequilibria were investigated. A detailed analysis of the mating types was made. No evidence was obtained for any departure from random mating at the protein loci. There was a significant tendency amongst the loci and samples for the inbreeding coefficients of the successful breeders to be negative. Significant assortative mating was found with respect to weight and tail-length in one population.