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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Chemical communication in wild Norway rats (Rattus norvegicus Berkenhout)

Landete-Castillejos, Tomás January 1997 (has links)
This study examined the urine and faecal scent marking behaviour and investigatory responses of wild Norway rats (Rattus norvegicus Berkenhout) kept in large, semi-natural enclosures to assess the role these scents play in their communication system. For the first time, this study has shown that Norway rats deposit faecal scent marks in response to odour cues and form latrines. The spatial distribution of faeces was highly uneven. Most faeces deposited in open areas were found in clusters occupying less than 1 m2 which were termed latrines. Rats spent more time at feeders and in other areas which were almost devoid of faeces than at these latrines. This suggests that latrines were created deliberately, perhaps for communication. Rats discriminated among faeces from different donors with respect to their investigation, presumably using olfactory cues. They faecal marked in response to urine cues from rats belonging to other colonies, although they did not faecal mark in response to their own urine cues or to a novel non-social stimulus (clean tiles). Investigation and faecal marking was aimed mainly towards urine from individuals of the marker's own sex. This suggests that faecal marking may play a role in communication between competitors. Urine was deposited as discrete marks around the enclosures, in an uneven distribution. The highest density of marks was found by the enclosure walls and nest areas. Rats showed a greater urine marking response towards introduced clean surfaces than towards surfaces they had already marked, ensuring that their home area was always covered with their urine marks. Close monitoring of urine marking on clean surfaces showed that male -rats had a marking rate three times greater than that of females. This could not be attributed solely to weight differences between males and females. Rats also urine marked in response to urine deposited by rats from other colonies. Urine from unfamiliar rats of the subject's own sex stimulated more investigation than urine from the opposite sex, though donors were immature. These results suggest that urine marking also plays a role in communication between competitors. Testing individuals in their home enclosure, using scent marks deposited naturally by rats, and the contexts in which scent stimuli are deposited by donors (e. g. as part of their home range) and found by residents (e. g. finding intruder's home range marks in the resident's home range) were essential factors in determining their response to olfactory cues. The importance of these factors is discussed.
2

Mother-offspring vocal communication and temperament in cattle

Padilla de la Torre, Monica January 2013 (has links)
Very little is known about cattle vocalizations. The few studies available in the literature have been conducted using animals under stress or very intensive husbandry conditions. Similarly, the individual consistency of behaviour in cattle has rarely been considered except in applied studies of constrained and isolated animals, and no previous research has attempted to address a possible association between vocal communication and temperament in cattle. The studies reported here address these gaps in our knowledge. I found that cattle contact calls have acoustic characteristics that give them individualized distinctiveness, in both adult cows and calves. These results were confirmed using playback experiments, where I found that there is bidirectional mother-offspring recognition, as has been recorded in other “weak hider” ungulates. Additionally, using visual and acoustic stimuli, I assessed individual cattle temperament. The results showed that there was no individual behavioural consistency in responses to a novel object presentations. However, calves behaved consistently more boldly than cows. Furthermore, there was significant individual consistency in responses to vocalisations of heterospecifics, when they were played back through a speaker in the field. Surprisingly, no correlations were found between the ability of cattle to identify their own mother/offspring and the acoustic features of their vocalisations, or behavioural responses in any other context. There were, however, significant correlations between one characteristic of vocalisations in adult cows (formant spacing) and the boldness of behavioural responses to both novel objects and auditory stimuli. Additionally, higher F0 in calf contact vocalizations correlated with boldness in the auditory stimuli experiment. These relationships imply that vocalisations may encode information about individual temperament, something which has rarely been documented. Surprisingly, no strong correlations were found between the behavioural responses to visual and acoustic stimuli, suggesting that individual consistency in behaviour across contexts was limited, and that behavioural plasticity could play an important role in determining responses in different environmental contexts. Overall, my results contribute to our knowledge of animal communication in mammals from a bioacoustic point of view, and they are also potentially relevant to studies of vocalizations as indicators of cattle welfare.
3

The stochastic modelling of social and territorial behaviour

Blackwell, Paul Gavin January 1990 (has links)
This thesis considers mathematical models of the interaction between social and territorial behaviour in animals, mainly by probabilistic methods. Chapter 1 introduces the Resource Dispersion Hypothesis, which suggests that territorial behaviour plus dispersed food resources can explain the existence of social groups, and describes an existing model of the process, due to Carr and Macdonald. In Chapter 2 the model of Carr and Macdonald is analysed, and in Chapter 3 an improved model is suggested and its main properties derived, primarily using renewal theory. Chapters 4 and 5 consider various spatial models for territory formation, and the effect, of spatial factors on social behaviour, using analytic and simulation-based methods. Chapter 6 considers the evolution of social behaviour using both discrete-time deterministic models and branching processes to investigate the viability of different strategies of social behaviour in the presence of dispersed resources.
4

The metabolomics of host-parasitoid interactions

Snart, Charles J. P. January 2015 (has links)
This thesis examines the relationship between insect life history and behavioural decisions and underlying cellular biochemistry, with particular focus on bethylid parasitoid wasps in the genus Goniozus. This comprises the first major body of work attempting to draw links between the underlying metabolome of an organism and its behaviour. This thesis further optimised the first known example of a combined LC-MS and NMR metabolomic approach capable of analysing extremely low biomass samples (<1 mg), a vital requirement when studying the behaviour of individual organisms. Part 1 of this thesis details the optimisation and validation of this metabolomic approach, whilst also examining the effects of aging on the metabolome of adult Goniozus wasps. Part 2 applies this approach to examine the effects of diet, host species and host aging on Goniozus wasp behaviour and biochemistry. Comparisons of the metabolomes of starved and honey fed wasps indicate that G. legneri is capable of utilising a carbohydrate rich diet as an energy source. Aged honey fed wasps possessed higher levels of large storage lipids, such as tri- and diacylglycerides, than starved wasps of the same age. Metabolomic analysis also detected a legacy effect on the metabolome of G. legneri associated with differences in the species of host each wasp was reared on. A similar legacy effect was confirmed when examining the metabolomes of wasps reared on artificially aged hosts. Whilst Goniozus wasp oviposition behaviour was altered by the species of host presented, no links between changes in a wasp’s metabolome and its resulting contest behaviour were found. Part 3 of this thesis examines the morphological, behavioural and chemical mimicry of another wasp, the hyperparasitoid Gelis agilis. G. agilis demonstrated an enhanced predation avoidance rate compared with control species, similar to that of the black garden ant Lasius niger. Agitation of G. agilis also resulted in the chemical emission of a known ant alarm pheromone.

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