The studies presented in this thesis were designed to investigate the effects of reduced sea water pH on the behaviour of intertidal decapod crustaceans, both within the context of the variations occurring naturally in the pH of rock pool habitats, and in relation to predicted changes to ocean pH resulting from ocean acidification and potential carbon dioxide (CO2) leaks from carbon capture storage (CCS) sites. Recent studies on marine fish have shown behavioural disruptions as a result of increased CO2 concentrations in sea water and reduced pH, but the effects on crustaceans are as yet unknown. The first two studies investigated the effects of reduced pH upon the olfactory behaviour of the prawn Palaemon elegans and the hermit crab Pagurus bernhardus, focussing on their responses to food odours. Short-term (five day) exposures to highly reduced pH (pHNBS = 6.60, 6.80) revealed disruptions to the chemo-sensory behaviour of both species with a reduction in their ‘sniffing’ response, and the inability of P. bernhardus to locate the chemical cue. This was also accompanied by elevated haemolymph chloride ions. in In a further study P. bernhardus was subjected to a longer exposure (60 days) and to a range of pH levels (pHNBS = 8.00, 7.90, 7.70, 7.35 and 6.80) in order to detect a threshold for the behavioural disruptions observed, and to determine if there would be any sign of acclimation over a longer period. A clear gradient in the disruptions to the chemo-sensory responses and survival rates of the hermit crabs, and disruption to a physiological marker (elevated haemolymph calcium ions), was found. Possible thresholds for disruption were also identified at levels that match predictions for ocean acidification and leaks from proposed CO2 CCS sites. Some of the crabs in the lower pH treatments exhibited a recovery in their responses by day 60, possibly indicating an acclimation effect. The presence of disruption to haemolymph ion concentrations in both the short and longer term hermit crab studies suggest a mechanism for behavioural disruption. In a final study the effects of reduced sea water pH on a more complex behaviour, involving decision making, was investigated. Reduced sea water pH was shown to disrupt the shell assessment and selection behaviour of P. bernhardus affecting its decision making processes, although not all crabs were affected in the same way. The work presented here therefore demonstrates that reduced sea water pH could have disruptive effects upon both information gathering, via chemo-sensory processes, and decision making in intertidal crustaceans. The mechanism responsible is unlikely to be due to changes in the odour molecule, or physical damage to receptor organs. Rather the observed disruptions could be due (a) to ionic changes, causing metabolic depression or interference with neurotransmitter function, or (b) to disruption to chemoreception per se. Such disturbances to key behavioural processes have implications for inter and intraspecific species interactions and population dynamics in the marine environment. Changes in pH are already experienced by intertidal animals for short periods when rock pools are emersed, but future anthropogencially-induced reductions in sea water pH are likely to cause more sustained and widespread disruptions with, as yet, unpredictable consequences. The differential responses observed between individuals in these studies may warrant further investigation as such differences may provide the basis for selection and adaptation to projected changes in ocean pH.

An understanding of the spatio-temporal dynamics of marine predator populations is essential for the sustainable management of marine resources. Tagging studies are providing ever more information about the movements and migrations of marine predators and much has been learned about where these predators spend their time. However little is known about their underlying motivations, making it difficult to make predictions about how apex predators will respond to changing environments. While much progress has been made in behavioural ecology through the use of optimality models, in the marine environment the necessary costs and benefits are difficult to quantify making this approach less successful than with terrestrial studies. One aspect of foraging behaviour that has proved tractable however is the optimisation of random searches. Work by statistical physicists has shown that a specialised movement, known as Lévy flight, can optimise the rate of new prey patch encounters when new prey patches are beyond sensory range. The resulting Lévy flight foraging (LFF) hypothesis makes testable predictions about marine predator search behaviour that can be addressed with the theoretical and empirical studies that form the basis of this thesis. Results presented here resolve the controversy surrounding the hypothesis, demonstrating the optimality of Lévy searches under a broader set of conditions than previously considered, including whether observed Lévy patterns are innate or emergent. Empirical studies provide robust evidence for the prevalence of Lévy search patterns in the movements of diverse marine pelagic predators such as sharks, tunas and billfish as well as in the foraging patterns of albatrosses, overturning a previous study. Predictions from the LFF hypothesis concerning fast moving prey are confirmed leading to simulation studies of ambush predator’s activity patterns. Movement analysis is then applied to the assessment of by-catch mitigation efforts involving VMS data from long-liners and simulated sharks.

The importance of tropical forests for global diversity and ecosystem function is well established in scientific literature, but is undermined by gaps in our knowledge of tropical ecosystems and species. Primates play important functional roles in these ecosystems, and despite constituting one of the most well-recognised taxa in the world, many species remain poorly studied. The Area de Conservación Regional Communal Tamshiyacu-Tahuayo (ACRCTT), located in the northeastern Peruvian Amazon, harbours one of the most diverse primate assemblages in the world and presents an ideal opportunity for the study of primate communities and mechanisms of their coexistence. Previous research has recorded the presence of an atypically coloured morph of monk saki monkeys (Pithecia monachus, sensu Marsh 2014) living in sympatry with a population of burnished sakis (Pithecia inusta, sensu Marsh 2014) in the reserve. In this study, the behavioural ecology of this potentially undescribed morph of saki monkey is described, using continuous focal data collected during the early wet season in the ACRCTT. The sakis were most often encountered in multi-adult groups and in the upper forest strata. The observed feeding strategies suggest that fruits and/or seeds constitute the sakis' primary food source in the wet season, although arthropods were also ingested during a large proportion of feeding records. Sex differences in behavioural patterns provide support for a difference in male and female investment in group defence. As only the monk saki morph was encountered during the study, the potential for seasonal habitat differentiation between the saki populations at the ACRCTT is discussed. A survey of primates in flooded and non-flooded forest areas at the ACRCTT was also conducted, in which nine of the 14 primate species recorded at the ACRCTT were encountered. Significant differences in the vertical distribution of primate groups provide evidence for vertical stratification in the ACRCTT primate community. This study contributes to previous research on the poorly-studied Pithecia genus, and provides insights into the mechanisms of niche differentiation between Pithecia and other primates.

The evolutionary ecology and population sytematics of the genus Phelsuma (Gekkonidae) were studied in the Seychelles. The distributions of all 18 Seychelles lizard species are described. These give little evidence for species turnover or the equilibrium model of island biogeography. Aspects of Phelsuma behaviour, social systems and reproduction were investigated. Phelsuma can digest pollen, which, with nectar may constitute a large part of the diet. On Praslin, P.sundbergi and P.astriata breed throughout the year, and partition their macro-habitat, micro-habitat and food resource dimensions such that P.sundbergi mainly occupies nectiferous and polliniferous palms and larger hardwood trees, whilst the smaller P.astriata is found on non-flowering palms and smaller trees. Interspecific competition is demonstrated by population density and habitat shifts between populations on islands in sympatry and allopatry. The biomass of Phelsuma geckos supported by coconut plantations in sympatric and allopatric situations tends to be relatively constant, such that there are either more small geckos or fewer large geckos. It is suggested that large body size is an adaptation to the defence of predictable and defensible food sources, such as palm flowers. Racial differention was investigated by multivariate morphometrics of shape, scalation and colouration, using appropriate techniques to negate ontogenetic effects. In the granitic islands, three phenetic aggregations of island populations were identified in the P.madagascariensis group, and two aggregations in the P.astriata group. Conventional taxonomic methods have failed to illustrate these patterns of phenetic variation, and new classification of island populations is proposed. Primary patterns of racial differentiation appear to have arisen from the sectioning of pre-existing clinal variation by rising Holocene sea levels, while secondary patterns relate to recent ecological selection pressures. P.abbotti populations on Aldabra and Assumption are sub-specifically distinct and not conspecific with granitic island forms. P.laticauda on the Farquhar group are probably not subspecifically distinct from Madagascan populations. All other coralline island populations appear to be recent introductions from the granitic islands.

Au cours d'une histoire évolutive singulière, les systèmes sensoriels des cétacés se sont adaptés à la vie en milieu aquatique. Aujourd’hui, alors que la littérature scientifique regorge de travaux sur leurs capacités acoustiques exceptionnelles, l’utilisation des sens chimiques par ces mammifères marins demeure encore largement méconnue. En effet, malgré quelques rares observations suggérant qu’ils pourraient détecter les composés sécrétés par leurs proies et leurs congénères, les arguments anatomiques et génétiques sont plutôt en faveur d’une régression voire d’une disparition de leurs capacités chémoréceptrices. Les cétacés auraient-ils perdu l’usage de ce canal sensoriel pourtant fondamental pour l’alimentation, la navigation et la reproduction chez les autres grands prédateurs marins ? L’objet principal de ma thèse était donc de déterminer si ces animaux sont capables de percevoir et d’utiliser les indices chimiques présents dans leur environnement en me basant principalement sur une approche comportementale. J’ai ainsi étudié les réactions des cétacés à dents (Odontocètes) et à fanons (Mysticètes) face à différents stimuli solubles ou volatiles, liés directement ou indirectement à leur alimentation. Après avoir mis en évidence, dans des conditions contrôlées, que le grand dauphin discrimine des extraits solubles de ses proies, j’ai développé un protocole permettant de mesurer la réponse des animaux (déplacements et comportements de surface) à des stimuli chimiques, dans leur milieu naturel. Des expériences en Méditerranée occidentale ont révélé que les grands dauphins et les globicéphales (Odontocètes) réagissent au sulfure de diméthyle (DMS), une molécule volatile émise dans les zones de forte productivité primaire. J’ai ensuite mesuré, chez la baleine à bosse (mysticète), la réaction au DMS et à des extraits de proies (krill) dans ses zones de reproduction (Océan Indien) et de nourrissage (Atlantique Nord et Antarctique). Les animaux exposés ont réagi par une augmentation de la fréquence respiratoire et, dans le cas de l’extrait de krill uniquement, par une attraction vers la source du signal (chemotaxis). Nos résultats comportementaux ayant mis en évidence une chémoréception fonctionnelle chez les cétacés, j’ai tenté dans un second temps d’identifier ses bases anatomiques et chimiques. J’ai ainsi initié l’exploration des muqueuses orales et nasales par des techniques d’immunohistochimie, ainsi que l’analyse chimique de leurs sécrétions (urines et fèces) à la recherche de potentielles phéromones. Cette approche innovante et multidisciplinaire a permis de dévoiler l’implication des signaux chimiques dans l’écologie des cétacés. Au-delà de leur aspect fondamental, ces résultats pourraient trouver des applications concrètes pour la gestion et la conservation de ces espèces emblématiques et menacées. / During the course of a unique evolutionary process, the sensory systems of cetaceans (whales, dolphins and porpoises) have secondarily adapted to life in an aquatic environment. While the extraordinary acoustic capacities of these animals have been widely studied, surprisingly little is known about their chemosensory abilities. The results of some sparse behavioural studies suggest that cetaceans can detect molecules secreted by, for example, a prey or congener. In contrast, anatomical and genetic investigations have concluded that cetacean chemosenses are greatly reduced or even absent. This poses the question; have cetaceans truly lost the use of the sensory channels that play a major role in the feeding, orientation and reproduction behaviours of other marine predators? The main objective of this thesis was, therefore, to establish whether these animals are capable of perceiving biologically-relevant chemical cues and exhibiting a behavioural response. For this project, I studied the reactions of both toothed (Odontoceti) and baleen (Mysticeti) whales to various soluble or volatile food-related stimuli. I first worked with captive bottlenose dolphins (Tursiops truncatus) and showed they could discriminate soluble extracts of their piscine prey. I then developed a novel protocol to measure the responses (surface behaviour and movements) of cetaceans to chemical cues in their natural habitat. Using this protocol, experiments performed in the western Mediterranean Sea revealed that both bottlenose dolphins and pilot whales (Globicephala melas) react to dimethyl sulfate (DMS), a volatile molecule found in areas of high primary productivity. Using the same protocol, I subsequently measured the reactions of a mysticete species, the humpback whale (Megaptera novaeangliae) to DMS and to krill extract (their natural prey) in three different locations: in their reproduction zone in the Indian Ocean, and in their feeding grounds in the North Atlantic and Antarctic Ocean. I found that the humpback whales reacted with an increased respiratory rate to both stimuli and that the krill extract also attracted them (chemotaxis). As the results of the behavioural studies suggested the presence of functional chemical senses, I initiated two further studies; (1) a neuroanatomical and immunohistochemical exploration of tissues in the oral and nasal pathways, in order to identify potential chemosensory receptor cells in four species of odontocete, and (2) a chemical analysis of odontocete secretions (urine or feces) in search for potential semiochemicals. Overall, this innovative and multidisciplinary research project revealed that chemical signals are potentially very important in the behavioral ecology of cetaceans. Moreover, these results contribute not only to our fundamental knowledge of the sensory biology of these animals, but they could also have important practical implementations in the conservation of these iconic and threatened species.

Network reciprocity describes the emergence of cooperative behaviour where interactions are constrained by incomplete network connectivity. It has been widely studied as an enabling mechanism for the emergence of cooperation and may be of particular interest in explaining cooperative behaviours amongst unrelated individuals or in organisms of lower cognitive abilities. Research in this area has been galvanised by the finding that heterogeneous topology promotes cooperation. Consequently there has been a strong focus on scale-free networks; however, such networks typically presuppose formative mechanisms based on preferential attachment, a process which has no general explanation. This assumption may give rise to models of cooperation that implicitly encode capabilities only generally found in more complex forms of life, thus constraining their relevance with regards to the real world. By considering the connectivity of populations to be dynamic, rather than fixed, cooperation can exist at lower levels of heterogeneity. This thesis demonstrates that a model of network fluctuation, based on random rather than preferential growth, supports cooperative behaviour in simulated social networks of only moderate heterogeneity, thus overcoming difficulties associated with explanations based on scale-free networks. In addition to illustrating the emergence and persistence of cooperation in existing networks, we also demonstrate how cooperation may evolve in networks during their growth. In particular our model supports the emergence of cooperation in populations where it is originally absent. The combined impact of our findings increases the generality of reciprocity as an explanation for cooperation in networks.

A study of the behavioural ecology of the woylie (Bettongia penicillata) was conducted between November 1986 and September 1987 on a population that had been introduced to Island A, Venus Bay in South Australia. The primary aim of the research was to establish the reasons for the success of this population of approximately 20 individuals which survives in an environment which is considerably different from the pockets of forest and woodland habitats comprising the present range of this species in Western Australia. This knowledge will assist wildlife authorities to identify suitable reintroduction sites within the former mainland range of B. penicillata. Scat analysis revealed that woylies on Island A consumed a catholic diet of dicotyledon leaf material, seasonal fruits and berries, and invertebrates. Endomycorrhizal fungal spores were common in scats during spring and are possibly derived from the gut of Scarab beetle larvae that were present in the scats at this time. Fungi are an insignificant dietary component of woylies at Venus Bay. The home ranges of woylies on Island A overlapped considerably and were significantly smaller than the "feeding" areas recorded for Western Australian conspecifics. Separate "feeding" and "nest" areas could not be identified on Island A as refuges were dispersed throughout the home range and were at a density of approximately three times that reported for Western Australian woylies. The refuge sites used by woylies on Island A were relatively simple constructions and contrasted with the more complex double-layered structures described for mainland woylies. Refuge sites on Island A were generally located beneath dense bushes. They provided little protection from prevailing temperature and relative humidity but did provide cover and ameliorate the effects of insolation. Refuges were exclusive to individuals. Males maintained a greater degree of spatial separation from one another during refuge occupation than they did from females, or females from each other. No significant difference between male and female body masses was detected, while the mean body mass recorded in December was significantly higher than at other times. The woylies at Venus Bay had significantly lower masses than those reported for a population of woylies at Tuttanning in Western Australia. The limited genetic base of the founding population and competition for food among this high density population are the most likely reasons for the lower masses of woylies on Island A. This study demonstrates that woylies can be successfully introduced into a wild, modified environment if their basic habitat requirements of suitable cover and diet are met. A broad diet, the abundance of suitable food species and adequate refuge sites within a small area, together with the absence of predators and fire, have all contributed to the success of the woylie population introduced to Island A. Active management is required to monitor and manipulate such small populations to ensure that genetic viability is maintained and the long term survival of the species is secured. Management: Recommendations 1. Monitor the population dynamics and genetic profiles of wild woylie populations in Western Australia. 2. Monitor the genetic profiles of woylies on Island A and other introduced populations. 3. Identify and acquire habitats similar to, and within, those of B. penicillata's former range, remove stock and exotic herbivores, implement and maintain predator control measures, and foster the growth of food species suitable for woylies. 4. Conduct research at proposed introduction sites to establish the fire regimes that would maintain adequate food and cover for woylies. 5. Introduce fresh genetic stock from wild Western Australian populations into the existing small populations in South Australia and simultaneously cull adults from the receiving population. 6. Maintain management practices to protect relic populations in Western Australia and newly established populations at introduction sites.

<p>For many years, primates have been considered to be animals with a poorly developed sense of smell. However, in recent years several studies have shown that at least some primate species have a high olfactory sensitivity for a variety of odorants. The present study used a two-choice instrumental conditioning paradigm to test the olfactory sensitivity for six aromatic aldehydes in four spider monkeys (Ateles geoffroyi). With helional, cyclamal,canthoxal and lilial all animals discriminated concentrations below 1 ppm from the odorless solvent, with single individuals even scoring better. With 3-phenyl-propionic aldehyde all animals detected concentrations below 2 ppb, and with bourgeonal even below 0.3 ppb. The detection thresholds of the odorants changed systematically with molecular structure. Addition of a dioxo or methoxy group to the benzene ring led to an increase in threshold values,while the absence of a methyl group close to the aldehyde moiety was linked to a low threshold value for the odorant. The study shows that spider monkeys have a well developed olfactory sensitivity for aromatic aldehydes.</p>

<p>Odor discrimination ability was tested in four female South African fur seals (<em>Arctocephalus pusillus pusillus</em>) using a food-rewarded two-choice instrumental conditioning paradigm. The seals’ ability to distinguish between members of homologous series of aliphatic ketones (2-butanone to 2-heptanone) and alcohols (1-butanol to 1-heptanol) was assessed. The results showed that three out of four seals successfully discriminated between all of their stimulus combinations in both classes of odorants. One seal succeeded to reach the discrimination criterion with all 2-ketones but failed with all 1-alcohols.</p><p>No significant correlation between odor discrimination performance and structural similarity of the odorants in terms of differences in carbon chain length was found in either of the two chemical classes. Furthermore, it was found that the 2-ketones were significantly better discriminated than the 1-alcohols. The fact that both classes of odorants are known to be present in the natural environment of seals provides a possible explanation as to why most of the seals were able to successfully discriminate between them. The results of the present study support the notion that the sense of smell may play an important role in behavioral contexts such as social communication, foraging and reproductive behavior of fur seals.</p>

<p>I investigated the understanding of human communicative motives in domestic dogs. Dogs use human communicative cues, like the pointing gesture when searching for hidden food, but it is uncertain how dogs interpret human communication. 32 dogs were presented with two communicative contexts in an object choice task experimental design. In a cooperative context the experimenter informed the subject where food was hidden by pointing and giving a verbal indication. In a competitive context the experimenter held out her arm towards the correct location in a stop gesture and firmly said no. To be successful in the competitive context the subject had to understand the experimenters communicative motive and make an inference from the prohibition (i.e. she would only prohibit it if there was something good there). The average correct choices were compared between the conditions. The dogs successfully followed the cooperative communication. They showed a trend towards choosing the baited cup in the competitive condition. A second study tested if the stop gesture affected the dogs’ choice, since it is not known how dogs interpret gestures. The pointing cue was now presented with the prohibiting command and the stop gesture was presented with the cooperative verbal cue. The dogs used the cooperative communication but did not understand the competitive context. A difference between the contexts was found. The dogs did not differentiate between the gestures. In conclusion dogs do not make inferences from competitive communication or prohibition but are specialized in utilizing cooperative communication</p>