The European eel is a mysterious animal and has a life cycle which has fascinated biologists for centuries. However many basic aspects of its life cycle and migrations remain unknown. European eels play a pivotal role in a balanced ecosystem both as a predator and prey species thus, understanding important ecological aspects of eel behaviour while resident in continental waters is vital in safeguarding and enhancing existing stocks. In recent years we have witnessed declines in juvenile eel recruitment across Europe. Results from this thesis indicate a drastic decline in yellow eel abundance in a transitional water body in Northern Ireland between 1967 and 2013, with current levels at 3.38% of historical levels in the Foyle estuary. Many populations across Europe are thought to be reduced to approximately 10% of their size in the yellow eel growth phase of their life-cycle and juvenile recruitment to this phase is as low as 5% compared with 30 years ago. However, the continental phase in which eels spend up to 30 years before undertaking their spawning migration allows managers to direct effective conservation strategies. The existence of two morphotypes “broad-headed” and “narrow-headed” in the European eel has been historically documented and this discrete head shape variation has interested biologists across Europe for a considerable amount of time. This phenotypic variation is widespread across the panmictic eel population. The findings presented in this thesis have highlighted the importance of understanding the ecology of alternative phenotypes which can exist in European eels co-occurring within the same habitat, and results suggest there may be potential consequences on life history as a result of foraging strategy undertaken in a growth habitat, with varying lipid stores and growth rates found between individuals. These alternative foraging strategies’ which manifest themselves in head shape variability corresponded to significant variation in space use and activity patterns in lacustrine growth habitat. This provides the first empirical evidence that observed morphological variation leads to significant differences in movement behaviour. Feeding specialisations during the eel growth phase can have important consequences for population dynamics. Feeding strategies may incur greater risks from, for example, parasites. Intensity levels of the invasive nematode parasite Anguillicola crassus were associated with differences in ontogeny and trophic ecology. Infestation levels of parasites in affected fish revealed a significant negative relationship between fish length and parasite intensity, with smaller individuals having higher parasite intensity than larger individuals. This study indicates that food intake and infection risk are linked in the host-parasite system. The growth phase for eels in continental waters ends with a transition called “the silvering process” following which individuals begin migrating downstream towards marine waters to undertake their spawning migration to the Sargasso Sea. Understanding migration behaviour, life stage specific mortality and migration success at this important life stage, is critical to effective conservation management. The unimpeded downstream movement patterns and migration success of small female and male silver eels investigated during this study revealed a low success rate to open ocean. Only 26% of eels which initiated downstream migration were detected at the outermost end of an acoustic array located at the mouth of a sea lough. Telemetry equipment functioned efficiently at all locations, therefore this suggests high levels of mortality during sea lough migration, or less likely, long-term sea lough residence by silver eel emigrants. The overall research approach employed in this study i.e the combination of morphometric, stable isotope analysis and telemetry has allowed vital information to be gathered. Managers can utilise this information to employ appropriate conservation strategies for Anguilla anguilla as well as guiding future research directions.

How do different animals cope with the vast environmental complexity they face from birth or hatching? If animals’ genes have not provided the necessary information, then exploration is essential for gathering information and learning about the surrounding world. Much of cognition research to date has focussed on what the different abilities of different animal species are, rather than how they actually process information. This thesis has taken a distinctive interdisciplinary approach to tackle this problem from different angles: asking how the senses, environment and different behavioural strategies influence exploratory learning – specifically in the naturally exploratory parrot and human child. It investigated parrots’ visual fields and their tactile ‘bill tip organ’ to describe the limits of their sensorimotor exploration, both in approach to and during manipulation of an object. A series of increasingly complex behavioural tasks were also conducted with parrots and children, involving different novel objects and causal problems. This project has given us insight into how we and other animals structure information in different situations. It has the potential to expand the understanding of a wide range of fields, such as in aiding how human developmental disorders may be treated, or by informing robotics design.

Sex in the jewel wasp Nasonia vitripennis is determined by whether eggs are haploid or diploid: the radically different male and female phenotypes share the same genome, showing that their sexual dimorphism is not genetic but rather a specific case of phenotypic plasticity. As a consequence, all of Nasonia’s genes are selected for both male and female fitness. The impact of this diverging selective pressure on the evolution of its genome and whether it is comparable to organisms with sex chromosomes are questions still largely unanswered. In this thesis, I develop and apply a set of tools for the integrative analysis of different aspects of Nasonia’s biology. I characterize the improved gene set of Nasonia and identify several lineage-specific gene family expansions. I provide an algorithm for detection and comparison of splicing and transcription signal from transcriptomic data in non-model organisms. Finally, I identify the different regulatory processes that enable generation of disparate phenotypes using network analyses on Nasonia’s developmental transcriptome. Nasonia’s transcriptome shows high amounts of sex-bias not tied to linkage groups or alternative splicing. Early development shows a prevalence of sex-biased interactions between transcripts rather than single-gene upregulation, and sex-biased networks are enriched in lineage-specific regulators.

The detrimental effects of inbreeding are well known, and they have been shown to be associated with lower levels of reproductive success, higher levels of parasitism and differences in disease susceptibility. To better understand large fitness differences between morphs in the colour polymorphic common buzzard, Buteo buteo, we investigated differences in the levels of internal relatedness between morphs. As the common buzzard mating system is non-random and the light and dark morph individuals are less abundant than the intermediates, it could be the case the extreme colour morph individuals are more inbred. However, no differences were found in levels of inbreeding. In birds, the physiological and behavioural consequences of colour polymorphisms are not widely known. Here we used an experiment to investigate the effect of this melanin-based polymorphism on nest defence behaviour in the common buzzard. Among males, light morphs were found to be significantly more aggressive to a perceived threat of nest predation than either intermediate or darkly coloured birds, while there was a non-significant tendency for the reverse among females. The level of aggression observed for each member of a pair was independent of the level of aggression shown by the other member. These results illustrate that polymorphisms can be associated with alternative reproductive tactics in birds, and suggest a possible link between the biochemistry of melanin production and individual behaviour. For most species living in seasonal environments, timing is an important determinant of the success of a breeding attempt. Individuals also face a trade off between current and future reproduction. Here we investigated whether colour morphs differed in their timing of breeding. Light-light and dark-dark pairs were found to breed earlier than the population mean, with light-dark pairs fledging chicks slightly later. Differences in reproductive strategies between morphs may account for the observed differences.

Membranes prepared from the olfactory mucosa of the rat show a high level of adenylate cyclase activity, typically 500 pmol/min/mg protein. The activity increases in the presence of odorants and is inhibited by calcium. Linkage of receptor to cyclase seems to be mediated by a G-protein. The existence of an odorant-stimulated adenylate cyclase in the rat is discussed. The olfactory tissue is found to contain high levels of intracellular cyclic AMP (ca. 40 pmoles/mg protein), almost twice that found in the brain tissue. Odorants appear to have no effect on these levels. The role of lipids in olfaction is investigated. The olfactory epithelium is found to be a rich source of phospholipids, comprising approximately 80% of the total lipids. The phospholipids identified are PC, PE, PS, SM, PA, PI, PIP, PIP=, accounting for approximately 41,23,9,11,4,10,2, and 2%, respectively, of the total phospholipids. 32P orthophosphate is incorporated into all the phospholipids; PIP and PIP2 show the highest rate of incorporation. Attempts are made to investigate the effect of odorants on this rate of incorporation. The fatty acid profile of the rat olfactory phospholipids is found not to be unique to the olfactory tissue. Elaidic acid 81:1t [n-9], however, seems to be present in higher concentrations than observed in other tissues. The fatty acids identified are 14:0, 15:0, 16:0, 16:1[n-9], 17:0, 18:0, 18:1c[n-9], 18:1t [n-9], 18:2[n-6], 20:0, 20:3[n-6], 20:4[n-6], 20:5[n-3], 22:0, 22:4[n-6], 22:5[n-6], 22:5[n-3], 22:6[n-3], 24:0, and 24:1[n-9].

The results suggest that nicotine vapour stimulates an in vitro olfactory preparation in three strains of rat and two strains of mouse, in a manner similar to known odorants. Preliminary experiments also suggest that nicotine is an odorant for human subjects. In the rat, the electro-olfactogram (EOG) produced by nicotine is attenuated by superfusion of the olfactory mucosa with the lectin concanavalin A. This reduction is prevented by a-methyl-D-mannoside, suggesting. that there is a glyco-moiety associated with at least one olfactory receptor responding to nicotine. A concanavalin A induced change in EOG response with varying odorant concentration for several odorants, including nicotine, can be explained by a single concanavalin A sensitive olfactory receptor with a dissociation constant for odorant binding in the order of 100 nM. The results also show that hydrophilic odorants are poor stimulants for the olfactory epithelium, supporting the hypothesis that the interaction of an odorant with the olfactory receptors involves hydrophobic effects. Spatial variation in response to four odorants, including nicotine, by the rat olfactory epithelium can be explained by a mosaic of olfactory receptors of various types in the olfactory epithelium. This observation is consistent with current hypotheses of odour quality determination by the olfactory mucosa. Nicotine binding sites in olfactory and respiratory epithelia. Binding studies show that there are sites for 3H(-) nicotine in both olfactory and respiratory preparations, though these sites may not be the same in each tissue. The binding parameters for olfactory epithelium are Ko=695 nM and Bmax=8.24 pmol/mg protein (mean of two experiments at optimal binding conditions). The olfactory epithelium binding sites differ from binding sites for nicotine described elsewhere for brain (e.g. Ko values from 0.2-60 nM, Bmax values from 1-100 fmol/mg protein) and for liver (Ko=0.2 nM, Bmax=5 fmol/mg protein). Some of the 3H(-) nicotine binding may be to an olfactory receptor though more conclusive evidence is required to substantiate this.

Potential alterations of host and parasite ranges are likely with climate change so an understanding of the host traits and ecological factors that can influence host-parasite interactions is vital for the effective protection of ecosystems. Accidental introductions of non-native species can place elevated stress on native ecosystems so that the examination of key species can act as early warning systems. The Eurasian otter, Lutra lutra¸ is a top predator and sentinel species for the health of European freshwater ecosystems and is therefore a suitable model for exploring parasite fauna introductions. In this PhD, the patterns and processes that define macro-parasitic infections were explored using evidence from post-mortems of 587 otters. Specifically, the invasive status of two helminths (Pseudamphistomum truncatum and Metorchis albidus: Trematoda; Opisthorchiidae) was investigated, both species having been identified in the UK otter populations for the first time within the last 10 years. Genetic variation, however, was similar across Europe indicating neither helminth is likely to have been a recent introduction to the UK., The distribution of both helminths as well as the only ectoparasite, Ixodes hexagonus (Arthropoda; Ixodidae), recovered from UK otters, were associated with abiotic factors, particularly temperature. The complexity of the parasite life cycles was investigated; otters act as a definitive host for both helminth species considered in this thesis and early stage intermediate hosts were identified for P. truncatum as the snail Radix balthica and the roach Rutilus rutilus. Metacercariae of M. ablidus were detected on chub (Leuciscus cephalus), rudd (Scardinius erythrophthalmus) and roach. Parasite aggregation and parasite fecundity of the P. truncatum populations were influenced by abiotic factors, region and season, whilst P. truncatum abundance was defined better by the biotic factors host age-class and condition demonstrating how multiple factors combine to produce parasite population dynamics in wild fauna. Ultimately, the data collated throughout this PhD was used to parameterise a susceptible-infected Susceptible-Infected (SI) model describing the host population dynamics of opisthorchiid trematodes. This model is applied to the P. truncatum system to examine which factors might determine the proportion of hosts that become infected.

The philosophy of data in science has been a matter of debate for many centuries. A theory-led view of data would suggest that data are only of use for an original stated purpose. I propose that this view would be falsified if a single alternative use were to be found for data and further suggest that the greater part of the value of data may lie beyond its original stated purpose. Benthic marine macrofauna data are collected from a large number of samples each year mainly to monitor human impacts. The data have diverse origins, sampling methods and usages. These are reviewed for surveys from the outer Thames region and the ultimate use of data is discussed. A taxonomy of data attributes is suggested. An equivalent classification is provided for attributes of marine species and the nature of the British marine fauna is reviewed in terms of these attributes, along with a thorough revision of the attributes of the prawn Palaemon longirostris. The comparability and quality considerations of benthic data are discussed using data from the NMBAQC Scheme. Data from Harwich Haven Authority surveys, designed to assess the impacts of port activities, are used to obtain information on the species recorded, which represents additional use of the data beyond the stated purpose. It is suggested that all data be considered in terms of their full potential use, in addition to their applicability to a stated aim.

No description available.

An extensive literature has documented the existence of suites of correlated behavioural traits (called behavioural syndromes) in a range of vertebrate species, as well as in some invertebrates. The existence and persistence of such behavioural syndromes is of both fundamental and applied interest and the main aim of the work described in this thesis was to examine sources of individual variation in risk-taking and aggression, as well as the circumstances under which those behaviours could be uncoupled. The study used two species of freshwater fish that have become something of a model to study behaviour: the three spine stickleback (Gasterosteus aculeatus) and the rainbow trout (Oncorhynchus mykiss). In chapter 1 I give a background on the current research on individual variability in behaviour, behavioural syndromes and coping strategies, with special reference to fish; as well as considering the implications of behavioural syndromes for evolutionary biology and aquaculture. Chapter 2 describes a long-term experiment on boldness, aggression and the relationship between them in sticklebacks that grew at different rates under two different competitive regimes. In one treatment (the low interaction condition) food was dispersed, while in the other (the high interaction condition), food was clumped. Fish were fed to excess in both treatments. Analysis of the relationship between risk-taking and some morphological variables showed that, in general, shy fish were heavier and longer than both bold and behaviourally intermediate fish, independently of their body condition. Fish from the low interaction condition were more aggressive than those from the high interaction feeding regime. Boldness and aggression were positively associated only in the fast growing fish from the high interaction competitive regime. Limited evidence suggests that individual personalities may influence reproductive success and other fitness-related traits in complex and context-specific ways. In the study described in Chapter 3, I used an indirect approach to relate fitness to personalities in sticklebacks. Specifically, I related hatching date of fry (used as an indirect measure of parental fitness) to their personalities (boldness and aggression). Individuals that hatched early were bolder than late hatched fish, whereas most of the shy individuals were found among the late bred fish. There were no detectable differences in aggression between early and late hatched fish, but there was a relationship between boldness and aggression independent of hatching date. In chapters 4 and 5, I describe studies of rainbow trout from two lines selected for breeding for low (LR) or high (HR) post-stress plasma cortisol response that have become something of a model system for studies of coping strategies in fish. In addition to striking differences in cortisol responsiveness, LR and HR fish show patterns of brain biochemistry, risk-taking and aggression that are typical of so-called proactive and reactive animals respectively. The results reported in chapter 5 strengthen this interpretation, by comparing behavioural flexibility and response to novelty in 3rd generation LR and HR rainbow trout. After being trained individually to find food in one arm of a T-maze, HR fish were able to found food strikingly faster than LR trout when the resource was moved to a different position. In contrast, LR fish were much less distracted by the presence of an unfamiliar object. Previous studies have shown that proactive animals develop and follow routines more strictly than do reactive animals, while the latter are more aware of changes in their environment. My results therefore give further support to the characterisation of LR and HR rainbow trout as showing proactive and reactive coping strategies. In chapter 4 however, I complicate this interpretation by showing that the relationship between boldness and aggression is flexible. Following transport from the UK to Norway, HR and LR fish switched behavioural profiles. In contrast to the results of previous studies, HR fish fed sooner in a novel environment and became dominant over LR fish in pairwise aggressive interactions. One year after transport, HR fish still fed sooner than LR fish, but no difference in social dominance was found. Among offspring of transported fish, no differences in feeding rates were observed, but as in pre-transported 3rd generation fish, HR fish lost fights for social dominance against size matched LR opponents. Transported fish and their offspring retained their distinctive physiological profile throughout the study, with HR fish showing consistently higher post-stress cortisol levels at all sampling points. Therefore the striking difference in cortisol responsiveness in these two strains of trout is on its own not sufficient to maintain distinct behavioural phenotypes. The work described in this thesis therefore extends current understanding of individual variability in behaviour and of behavioural syndromes by identifying circumstances under which risk-taking and aggression are uncoupled in two species of freshwater fish. It also suggests some potential consequences for fitness. In chapter 6 these results are discussed on the light of current research on animal personalities, behavioural syndromes, coping strategies and their implications for evolutionary biology. Particular reference is made to the existing literature on fish and the implications of those findings for aquaculture are also discussed.