Baited underwater camera (BUC) systems are becoming popular in the shallow water environment to monitor the relative diversity and abundance of fish and invertebrate assemblages. This thesis describes methods developed to use BUCs in temperate, tropical and Antarctic environments and their application to questions concerning the factors controlling shallow water marine biodiversity and abundance. In Chapter 2 the design and development of a BUC system suitable for attracting, identifying and counting temperate shallow water (< 30 m) fish and crustacean species on the West coast of Scotland is described. The use of BUC systems has been limited in temperate waters and a cost- and – time efficient method could be valuable to monitor the before and after impact of the proposed Scottish Marine Protected Area network. As a test of the BUC, deployments were made in Lamlash Bay no-take zone (NTZ) and in two control open sites to provide baseline data early in the life of the NTZ against which future BUC studies can be compared. The tropical Gulf of Aqaba supports unique coral reef fish assemblages and it is important to perform a study specific in this distinct biogeographical region to understand whether BUC surveys could be useful in this sensitive environment. In Chapter 3 we therefore compared the predatory fish assemblages recorded in BUC deployments to the established method of Underwater Visual Census (UVC) surveys in the northern Gulf of Aqaba. Abundance metrics from the arrival pattern of fish at the BUC did not correlate with population abundance estimates from UVCs and it was concluded that until improved methods of interpreting BUC data are developed the deployment of BUCs could be used to assess predator species richness but is not able to indicate relative variation in population abundance. Chapter 4 demonstrates how BUC systems can be used to gather data on a complicated ecological question in extreme conditions. A BUC system was used to examine the distribution of scavenging fauna in relation to the spatial variation in exposure to iceberg impacts experienced at difference iceberg scouring conditions and depths within Marguerite Bay. The results indicate that different scavenger species are adapted to high and low iceberg scouring environments and that they are distributed in accordance with the recognised pattern of decreasing iceberg scouring frequency with depth. The above studies used relative measures of abundance such as recording the highest number of individuals observed at a single time (MaxN). Such measures are limited in their usefulness but there are no robust means of estimating absolute abundance, especially for complex shallow water systems. In Chapter 5 a modelling approach, using a stochastic simulation, was developed and used to estimate population abundance for species commonly observed in the above studies. Model abundance estimates were generally found to be comparable to those from corresponding UVC transects. This modelling approach has the potential to substantially improve the ability of BUC systems around the world to assess fish and invertebrate diversity and abundance.

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Proboscis monkeys (Nasalis larvatus) are endemic to Borneo and live in habitats threatened by land clearance for agriculture, aquaculture and timber. This thesis examines the roles of structural and landscape characteristics on both short- and long-term habitat use through the first application of GPS tags to proboscis monkeys. In a comparison of four home range estimators, biased random bridges provided the best home range estimates given the GPS-collar dataset and landscape characteristics (Chapter 3). Differences in long-term ranging patterns of 10 individuals across a range of forest-block sizes and disturbance levels were examined, as well as daily and seasonal variation in movement and sleeping site selection. Using Light Detection and Ranging (LiDAR) structural metrics of the forest, as well as landscape characteristics, forest with taller canopies, forests in close proximity to river edges were found to be of particular importance to proboscis monkeys, and plantation edges were avoided (Chapter 4). Changes in daily and monthly movements were associated with seasonal changes in rainfall and potential food availability. Movement patterns also changed near forest edges, with faster, more direct movements near agricultural boundaries. Less rainfall, higher temperatures and brighter moon phases correlated with selection of sleeping sites in the forest interior (Chapter 5). By understanding the ranging requirements of proboscis monkeys, drone and GPS collar data were combined to inform conservation policy (Chapter 6). This thesis provides the most in-depth examination of proboscis monkey ecology to date. They appeared more generalist in their home range use and structural habitat requirements than previously realised, suggesting a higher degree of versatility and resilience to habitat loss and degradation. This study provides increased understanding of potential consequences of human-mediated disturbances and can be used to assist in the protection of this charismatic species and the management of degraded landscapes.

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In Scotland over the past 30 years the Nephrops fishery has expanded and is now the largest in Europe with landings in 1986 valued at over 㴍m. Much of the species biology is poorly understood, especially the early life history. The biology of larval and juvenile Nephrops is the subject of this thesis and the work reported has been conducted on Nephrops within the Firth of Clyde. Because Nephrops incubate their eggs externally (on their pleopods) they suffer progressive egg loss. Creels were set to capture ovigerous females incubating eggs at various stages of development to provide fecundity data and egg samples for a study of the biochemical changes associated with embryonic development. During the incubation period mean egg loss was estimated as 18% . Almost a fifth of the population were judged to have suffered additional egg loss, probably at the moment of spawning. Estimation of the mean number of eggs hatched per female per year took such losses into account and involved the use of length frequency information and a maturity ogive. The best estimate of the fecundity range was 985 - 1115 eggs hatched per female, which includes an allowance for the proportion of the population that may be biennial spawners. Lipids are the principal energy reserve utilized during embryonic development and full development requires 6 - 7 joules per egg. Most energy is expended during the later stages of development and is associated with a rapid uptake of water and salts. An aquaculture facility was developed and newly hatched larvae were reared under different culture conditions. Survival was found to be better in isolation compared to mass rearing conditions and initial periods of starvation in excess of 1 -2 days led to an increase in mortality. Larvae were reared over a temperature range of 8 - 20oC and relationships were derived between temperature and the rate of larval development for each zoeal stage. The development time increased for successive zoeal stages at each temperature and 16oC seemed to be the overall `optimum' temperature for development. A larval survey programme was conducted in the Lower Firth of Clyde (L.F.C.) to investigate temporal and spatial changes in larval abundance. The larval abundance data were used in conjunction with the temperature information obtained in the laboratory study to obtain a seasonal production estimate for the 1st zoeal stage of 177 x 108 larvae within the 876 square kilometres sampling area. This value, when used in conjunction with the mean number of eggs hatched per female per year, gave an estimate of 15.87 x 106 to 17.97 x 106 females for the L.F.C. spawning stock. Information on the vertical distribution of Nephrops zoeae was obtained over two 24h cycles, one coincided with a spring and the other with a neap tidal period. The distribution of the larvae was related to several environmental variables and compared with the light and pressure responses demonstrated under controlled laboratory conditions, 1st, 2nd and early 3rd stage zoeae demonstrated positive phototaxis and high barokinesis. No dramatic diel changes were detected in the vertical distribution of the larvae. Most remained between 6 to 38m depth during daylight hours. A limited nocturnal ascent resulted in peak larval abundance shifting from 16 to 5m depth. Shortly after dawn the larvae descended to their daytime distribution. Depth regulation is probably achieved by light and pressure sensitivity and may be influenced by the position of the pycnocline. During the 3rd zoeal stage the light response changed from photopositive to photonegative and Nephrops may first come into contact with the sea bed towards the end of this stage. Substratum selection and settlement behaviour experiments were conducted with early postlarval stages and these suggested that the 1st postlarval stage is a transitional form between the planktonic and benthic environments.

The aim of this project was to elucidate the mechanisms behind maternal inbreeding depression, using a model avian species, the zebra finch Taeniopygia guttata. Inbreeding can reduce the fitness of inbred animals beyond its negative effects on early survival, through reduced fecundity of inbred animals that survive to reproductive age. In particular, inbreeding has been found to cause a decline in hatching success and early survival of the offspring of inbred mothers. I examined the underlying causes of maternal inbreeding depression by observing the effects of one generation of full-sibling mating on life-history and physiological traits in the zebra finch. The aims of this project were to separate the effects of maternal inbreeding on egg production and subsequent offspring care on the fecundity of inbred females and to examine the possible underlying causes of maternal inbreeding depression. The study explored the following questions; • Does maternal inbreeding lead to a reduction in egg production, either in the number, quality or size of eggs produced? • Do inbred females reduce the level of antimicrobial proteins in their eggs compared to outbred females? • Does inbreeding lead to a reduction in either incubation attentiveness or incubation temperature in females? • Does inbreeding in the egg-laying mother lead to a decline in offspring survival or growth? • Does inbreeding in the foster mother lead to a decline in offspring survival or growth? • Do inbred birds have higher maintenance costs, i.e. higher resting metabolic rates than outbred females? After generating inbred and outbred (control) females from full-sibling and non-related pairs respectively, females were paired with unrelated outbred males at the age of around six months old. The first clutch was removed for analysis of egg production (chapter two). The females were immediately allowed to lay replacement clutches, which were cross fostered among nests of inbred and control females. I then compared incubation attentiveness between inbred and control females using this replacement clutch (chapter 3). Through the cross fostering design I was able to separate the effects of inbreeding in the egg laying (chapter 2) and incubating mother (chapter 3) on offspring viability by comparing offspring growth and survival between treatments. When the same group of females were two years old I compared the resting metabolic rate of inbred and control females by measuring oxygen consumption of resting females in an open flow respirometry system (chapter 4). In chapter two I examined the effects of inbreeding on a key stage of reproductive investment; egg production. I found a reduction in both egg mass and yolk mass in inbred females compared to control females. However, there was little evidence to suggest that the level of antimicrobials deposited to the egg differed with the inbreeding status of the female. Inbreeding in the egg laying mother was found to affect hatchling mass through interactive effects with replicate and clutch size. Inbreeding in the egg egg-laying mother also affected post-hatching survival, although this effect was mediated by hatching order. In chapter three I investigated the effects of maternal inbreeding on incubation behaviour. Inbred females reduced their incubation attentiveness, but did not reduce average incubation temperature, compared to control females. However, the overall incubation attentiveness experienced by clutches did not differ between treatments due to complete compensation by the partners of inbred females. This is perhaps why there was no significant decline in either hatching success or hatching mass of offspring cross fostered to inbred females. In chapter four I examined the effects of inbreeding on resting metabolic rate by measuring resting oxygen consumption (VO2) of inbred females compared to control females. Resting VO2 (corrected for body size) was higher in inbred compared to control females. Inbred females also showed increased central organ mass (heart plus liver) for their body size compared to control females. Resting VO2 (corrected for body size) was positively was correlated with central organ mass (corrected for body size) and negatively correlated with peripheral organ mass (corrected for body size). I also found a positive correlation between resting VO2 and the ability to evade capture (rank capture order from a flight aviary). My results suggest that the reduced survival rates of the offspring of inbred females may be caused by reductions in maternal investment, since both egg size/quality and incubation attentiveness have previously been found to positively correlate with offspring viability. The finding that resting VO2 increased with inbreeding may suggest that inbred females showed reduced maternal investment in egg production and incubation attentiveness due to higher energetic costs of self-maintenance. Resting metabolic rate has been found to be associated with a wide range of life-history traits and so this finding could have important implications for the fitness of inbred animals. These findings are novel and shed light on the previous observations that maternal inbreeding can reduce early and long-term survival of the offspring of inbred individuals in wild populations.

Aedes aegypti (Diptera: Culicidae) is the major vector of a number of arboviruses including dengue. Understanding how semiochemicals might mediate the key behaviours of mating and oviposition should lead to a better understanding of the biology of Aedes aegypti and might also lead to practical vector control applications. The results of behavioural investigations into putative egg associated oviposition pheromone have been contradictory and incomplete in that they failed to control numbers of eggs in their experimental design. A previous study found behavioural evidence for a male produced sex pheromone, but an upwind anemotactic response of females was not tested and it could be argued that the experimental design was not robust. For this thesis no-choice and choice bioassays were carried out to test the oviposition response of gravid females to both specific numbers of con-specific eggs and methanol extract of eggs. An olfactometer was designed to test the upwind anemotactic response of virgin females to male headspace volatiles with and without host odour cues. These male odours were also used to bait BG-sentinel traps in the field. While no evidence was found that was consistent with an egg associated oviposition pheromone in Aedes aegypti, results from both laboratory and field based experiments suggest that males might emit a pheromone in response to host odour that attracts virgin females. Results from experiments in which males were not exposed to host odour suggest that host odour might be required to stimulate pheromone release.

Nutritional conditions during early life can strongly influence the development of an organism in terms of immediate effects on early growth rates but also by shaping key life history traits later. After a period of nutritional deficit in early life, some animals have been found to accelerate their growth to compensate for the bad start once conditions have improved. There is experimental evidence demonstrating that compensatory growth can carry associated long-term costs, such as reduced locomotory capability and reduced investment in reproduction. Further, it has been proposed that oxidative stress may play an integral role in evoking these costs, as a result of a higher metabolic activity during compensatory growth. However, there is currently little literature available to attest this. Dietary-acquired antioxidants are proposed to support the endogenous antioxidant system in preventing oxidative stress and are therefore suggested to mediate life history trade-offs. In this thesis, resveratrol and carotenoids (potential antioxidants) were supplemented in the diets of three-spined sticklebacks Gasterosteus aculeatus in order to assess whether they were able to mitigate the negative effects associated with compensatory growth by reducing oxidative stress. Two important components of oxidative stress, antioxidant enzyme activity levels and oxidative damage were measured. This thesis showed that food restrictions early in life resulted in a slowing of growth which was subsequently fully compensated for by acceleration in growth once food conditions were restored. Despite adopting different growth patterns, these fish achieved the same average size by sexual maturity as their control growth peers. However, compensatory growth was found to result in significant costs in later life including reduced cognitive and locomotor performance (Chapter 2). Additionally, it was demonstrated that food supplemented with resveratrol had some beneficial effect on cognitive performance in comparison with same-age controls (Chapter 2). However, resveratrol and carotenoid manipulations did not influence locomotor performance (Chapter 2). This result implies that dietary antioxidants were unable to offset the damage to swimming performance caused by compensatory growth, and that their generally beneficial effects in the diet do not affect all aspects of performance similarly, or to the same extent. Both dietary resveratrol and carotenoids influenced oxidative stress status (Chapter 3). Their role in the antioxidant system appears important and complex in that there were several statistical interactions between these dietary antioxidants and endogenous antioxidant enzyme levels. These enzymes play key roles in the defence of reactive oxygen species (Chapter 3). Fish supplemented with a diet higher in carotenoids were found to have reduced levels of oxidative damage to proteins (Chapter 3). This result suggests that although carotenoids appear to be unimportant antioxidants for birds, these findings should not be generalised across all taxa. Carotenoid and resveratrol availability influenced female reproductive investment (Chapter 3). Females on a diet supplemented with carotenoids had larger clutches suggesting that carotenoids played a positive role in their reproduction (Chapter 3). However, this was only apparent when the fish had not also been supplemented with resveratrol, suggesting that resveratrol may have imposed a detrimental effect on egg production (Chapter 3). Further, male reproductive investment in sexual ornamentation and nest building ability was also influenced by these dietary antioxidants in a similar fashion (Chapter 4: males fed a diet higher in carotenoids had significantly brighter throats at two crucial stages of the breeding season, while resveratrol had no positive effects on the intensity of the males’ red throat signals). This is contrary to the so-called Red Herring hypothesis which suggests that carotenoid-based sexual signals advertise not the carotenoids themselves but other colourless antioxidants. In addition, males fed a diet lower in carotenoids took longer to both begin and complete nest building, whilst resveratrol had no influence on any aspects of nest building (Chapter 4). The process of mate choice has been suggested to be costly in many species, since the assessment and comparison of potential mates is an energetically demanding process and hence likely to increase oxidative stress. Therefore, it was predicted that resveratrol would facilitate active mate choice in females through beneficial effects associated with its antioxidant properties. Indeed, females supplemented with resveratrol spent significantly more time associating with males than females that had not been fed resveratrol (Chapter 5). These female mate-choice experiments also demonstrated that resveratrol and compensatory growth did not impact male attractiveness (Chapter 5), suggesting that the females did not receive any alternative (and potentially important) mate cues mediated by resveratrol that were independent of the carotenoid-based signal. There has been growing evidence in the literature demonstrating that resveratrol has neuroprotective properties, therefore reducing age-related reduction in cognitive performance, and this was also supported in the results of this thesis produced in Chapter 2. Chapter 6 investigated whether the supplementation of resveratrol and carotenoids reduced the rate of ageing in three-spined sticklebacks in terms of exploratory and anxiety-related behaviour in an open field test, measured during early life and again in adulthood. However, in contrast to expectations, males that were not fed resveratrol had the greatest increase in exploratory activity across the experimental period (Chapter 6). Overall, this thesis demonstrates that dietary manipulation with resveratrol (alongside carotenoids) affected numerous life history traits throughout the three-spined stickleback’s lifespan. The evidence produced in this thesis strongly suggests that numerous aspects of an organism’s performance can be affected by key nutrients, over and above calorie intake which is often misconceived as having unprecedented importance. These effects can be subtle in some scenarios and much more complex in others and they do not necessarily generalise terribly well across taxa. Moreover, by measuring oxidative stress status alongside later life performance in these fish, this thesis helps elucidate the precise roles these antioxidants have in influencing oxidative stress and alleviating the negative effects associated with compensatory growth.