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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.
21

The Importance of Curation: a Case-Study of the Subfossil Lemur Collection in the Museum of Evolution, Uppsala University / Kureringens betydelse: en fallstudie av Evolutionsmuseets paleontologiska samling av subfossila lemurer

Lindkvist, Maria January 2016 (has links)
In times when many natural history museums experience financial cuts, it is important to show why museums matter, what they can offer, and what they mean for both the public and the scientific society. The collections are the heart of the museum and they need to be well-managed in order to attract visitors (both researchers and public). Curation of collections is an essential part of the museum operation but it may be affected by understaffing and/or lack of physical space. If collections in need of curation (especially old collections) are left unattended, they may lose their scientific value.     This project was done in order to show the importance of curation and its possibility to increase the value of a collection. The aim of this project was to show that a thoroughly explored and well curated collection becomes more accessible and interesting for internal and external sources and thereby the scientific and public value increases. This was conducted as a case-study of the collection of subfossil lemurs at the Museum of Evolution, Uppsala University. The collection was catalogued, its historical background was studied, and the old collection description was reviewed. The collection catalogue produced (Appendix D) has increased the availability and scientific value as it is now easier to get an overview of the collection, the catalogue include updated anatomical and taxonomical specimen descriptions, it is possible to administer loans on collection specimens, and the catalogue data can be published in accessible databases. The historical background (Appendices A and B) has shown that the collection has connections to other Swedish museum collections in Stockholm, Gothenburg, Malmö, and Lund. It is possible to use the information in the historical background in an eventual exhibition. This has increased the public value. However, it is possible to further increase both the availability and the value of the collection and some suggestions are given. / Denna uppsats handlar om kurering, alltså om omhändertagande av samlingar som finns på museer. Det finns många olika typer av museer, t.ex. naturvetenskapliga museer, historiska museer, konstmuseer, friluftsmuseer och hembygdsmuseer. Detta arbete är främst inriktat mot naturvetenskapliga museer med paleontologiska samlingar och varför det är viktigt att de finns och varför de ska tas om hand. Vidare visas hur en samling kan bli mer lätttillgänglig och hur dess värde kan höjas genom att noggrant kureras, katalogiseras och utvärderas.     Projektet utfördes som en fallstudie av den samling av subfossila lemurer som finns på  Evolutiosmuseet i Uppsala. I den sammanställning som gjordes av samlingens historiska bakgrund framkom det att folkskoleläraren Bertil Ljungqvist samlat in materialet under en expedition till Madagaskar mellan åren 1926 och 1930. På denna expedition samlades även zoologisk, botaniskt och kulturella föremål in. Dessa föremål finns idag utspridda på olika museer i Uppsala, Stockholm, Göteborg, Malmö och Lund. Det historiska bakgrund som sammanställdes i detta projekt kan användas av dessa museer om materialet ska ställas ut. Alla förmål i samlingen av subfossila lemur har fått uppdaterade beskrivningar i den nyskapade katalogen. Katalogen gör det möjligt att på ett enkelt sätt få en överblick av samlingen, det är nu även möjligt att låna föremål och samlingen är ett steg närmare att publiseras i en databas. I och med detta projekt har samlingen blivit mer tillgänglig, den är lättare att använda i olika sammanhang och därmed kan även sägas att värdet av samlingen har ökat. Dock finns det stora möjligheter att ytterliggare öka både värdet och tillgängligheten.
22

Parfum de figues : approche évolutive de la communication entre une plante, ses insectes pollinisateurs et ses vertébrés disperseurs / « Parfums de figues » : an evolutionary approach to communication between a plant, its pollinating insects and its vertebrate seed dispersers

Soler, Catherine 03 December 2010 (has links)
Pour l'ensemble des organismes vivants, la communication (intra ou interspécifique) est le véhicule de l'information, un élément central dans l'interaction entre individus. Elle a ainsi des impacts primordiaux sur les traits d'histoire de vie des espèces, et est donc façonnée par la sélection naturelle. Au cours de cette thèse, nous nous sommes intéressés à l'évolution de la médiation chimique, c'est-à-dire à la transmission d'informations par voie chimique entredeux individus, dans les interactions plantes/animaux. Nous avons choisi le modèle figuier et ses partenaires mutualistes, de la guêpe pollinisatrice aux vertébrés disperseurs de graines. La médiation chimique (ici émission de bouquets volatils constitués de terpènes et de dérivés benzéniques et d'acides gras) permet aux figuiers d'assurer leur reproduction, par attraction des pollinisateurs et des disperseurs de graines. Il existe environ 800 espèces de figuiers à travers le monde, à distribution principalement tropicale. Les figuiers, fructifiant toute l'année,sont souvent qualifiés d'espèce clef de voute des écosystèmes tropicaux, car ils assurent ainsi le maintien des populations de frugivores dans les forêts tropicales dans les périodes où très peu d'espèces d'arbres fructifient. L'interaction figuier/disperseur est plutôt généraliste, alors que le mutualisme figuier/pollinisateur, un exemple de nursery pollination, est hautement spécifique et obligatoire. Au cours de cette thèse, nous avons mis en évidence que les contraintes phylogénétiques et géographiques exercées sur la médiation chimique étaient négligeables, alors que les pressions de sélection que représentent les mutualistes sont nettement plus importantes dans l'évolution de cette médiation. Ainsi, sexe et stade phénologique du figuier et identité du partenaire mutualiste sont des informations qui peuvent être portées par la médiation chimique. Notre approche, globale et multidisciplinaire, des interactions entre les figuiers et leurs partenaires mutualistes aux deux phases de dispersions des gènes de la plante, permet une meilleure compréhension de l'évolution de la communication, et montre que les pressions façonnant ce message façonnent l'interaction elle-même. / For all living organisms, communication (intra-or interspecific) is the vehicle of information, anelement central to interactions among individuals. It thus has fundamental impacts on lifehistory traits of species, and is shaped by natural selection. This thesis is concerned with thechemical mediation of communication, i.e., the transmission of information by chemical signals,in the context of animal-plant interactions. We chose as a model system the interactionsbetween figs and their mutualist partners, including both pollinating fig wasps and vertebrateseed dispersers. Chemical mediation (in this case the emission of bouquets of volatilecompounds comprising terpenes, benzenoids and fatty acid derivatives) enables figs to ensuretheir reproduction by attracting pollinators and seed dispersers. There exist about 800 species ofFicus worldwide, principally in tropical regions. Figs, which fruit throughout the year, are oftenconsidered keystone species of tropical ecosystems, because their year-round fruiting maintainspopulations of seed-dispersing frugivores during fruit-poor lean seasons'. Interactions betweenfig species and seed-dispersing animals are generalist' (i.e., broad food species ranges), whilefig/pollinator mutualisms, examples of nursery pollination' systems, are highly species-specificand obligatory. In this thesis, we showed that phylogenetic and geographic constraints actingon chemical mediation are negligible, whereas selection pressures grounded in pollination andseed-dispersal mutualisms play a strong role in shaping the evolution of chemical mediation.Thus, chemical mediation carries information such as the sex and developmental stage of thefig tree, as well as the identity of the mutualistic partner. Our comprehensive, multidisciplinaryapproach to interactions between figs and their mutualist partners in the two phases ofdispersal of the plant's genes leads to an improved understanding of the evolution ofcommunication, and showed that the selective pressures shaping the message are also thoseshaping the interaction itself.
23

Infant Development and Maternal Strategies in the Two Largest Lemurs: The Diademed Sifaka (Propithecus diadema) and the Indri (Indri indri).

Weir, Jody Suzanne 22 August 2014 (has links)
At least half of the world’s primate species are currently threatened with extinction. Slow life histories combined with rapid habitat loss and hunting in recent years has heightened the extinction risk for many species, including the two largest extant lemurs, the diademed sifaka (Propithecus diadema) and the indri (Indri indri). Both species belong to the taxonomic family Indriidae, have similar adult weights, and occur in sympatry in certain areas of the montane rainforests of eastern Madagascar. Both species are adapted for folivory however I. indri spend considerably more time feeding on leaves than do P. diadema resulting in several energy-saving adaptations in I.indri. In this dissertation, I explore infant development and maternal strategies of these critically endangered primates with the goal of increasing our knowledge of reproduction and ontogeny in both species. Although previous studies have elucidated key differences in adult behaviour, there is a dearth of information on infants and lactating females in either of these two species. Between June and December of 2011 and 2012, I collected continuous time focal animal data, in Maromizaha forest, to examine behavioural patterns of 12 infants and their mothers from 0 – 33 weeks. In addition, I developed a framework to define and quantify the weaning process and facilitate comparisons across different species and studies. P. diadema infants developed feeding competency and independent locomotion faster than did I. indri infants however both species were consistently feeding independently more than they were suckling by week 20. The process of feeding ontogeny in I. indri was likely accelerated by coprophagy, as all infants of this species consumed their mother’s feces regularly from 10 – 15 weeks old. Lactating females of both species spent more time feeding in mid-lactation when maternal investment was the highest. The prolonged inter-birth interval in I. indri is suggested as another adaptation that reduces energetic expenditures. In addition, the protracted period of close contact with their mother may offer infant I. indri more time for social learning of the mother’s diet and the group song and for developing competency in vertical clinging and leaping without a tail for balance and support. / Graduate
24

The Psychology and Evolution of Foraging Skills in Primates

Rosati, Alexandra January 2012 (has links)
<p>Primates in the wild face complex foraging decisions where they must assess the most valuable of different potential resources to exploit, as well recall the location of options that can be widely distributed. While differences in diet and ecology have long been thought to be an important factor influencing brain evolution in primates, it is less well understood what psychological abilities animals actually use when making foraging decisions. This dissertation examines cognitive domains that play a crucial role in supporting foraging behaviors--spatial memory and decision-making--by integrating both psychological and biological approaches to behavior. In particular, the research presented here examines multiple species of primates to address the cognitive skills that different animals use to solve foraging problems (at the proximate level of analysis), as well as why some species appear to solve such problems differently than other species (at the ultimate level of analysis).</p><p>The first goal of the dissertation is to compare closely-related species that vary in ecological characteristics, in order to illuminate how evolution shapes the cognitive skills used in foraging contexts. This component focuses on comparisons between chimpanzees (Pan troglodytes) and bonobos (Pan paniscus), humans' closest extant relatives. In addition, this component reports comparisons amongst strepsirrhines (Lemur catta, Eulemur mongoz, Propithecus coquereli, and Varecia subsp.) to model cognitive evolution in a taxonomic group with greater ecological diversity than Pan. The first two chapters test the hypothesis that more frugivorous species exhibit more accurate spatial memory skills, first by comparing apes' spatial memory abilities (Chapter 2), and then by comparing four species of lemurs on a related set of spatial memory tasks (Chapter 3). In subsequent chapters, I examine apes' decision-making strategies to test the hypothesis that chimpanzees are more willing to pay decision-making costs than are bonobos, due to differences in their feeding ecology. I focus on preferences about the timing of payoffs (Chapter 4); preferences about risk, or the variability in payoffs (Chapters 4 and 5); and preferences about ambiguity, or knowledge about available options (Chapter 6). </p><p>The second goal of the dissertation is to compare the psychological mechanisms that human and nonhuman great apes use for foraging, in order to identify potentially human-unique cognitive abilities. In terms of spatial memory, I examine whether other apes also exhibit human-like patterns of spatial memory development (Chapter 2). In terms of decision-making, I examine whether apes exhibit a suite of human-like biases when making value-based choices. In particular, I test whether emotional and motivational processes, which are critical components of human decision-making, also play a role in apes' choices (Chapters 4); whether apes are sensitive to social context when making economic decisions (Chapter 5); and whether apes are sensitive to their degree of knowledge when making choices under uncertainty (Chapter 6). Finally, I directly compare human and ape preferences on a matched task to assess whether humans use any unique psychological abilities when making decisions about risk (Chapter 7). In sum, this dissertation links studies of mechanism with hypotheses about function in order to illuminate the evolutionary roots of human's unique cognitive phenotype.</p> / Dissertation
25

Social information gathering in lemurs

Ruiz, April M. January 2010 (has links)
By investigating the cognitive capacities of non-human primates, we can begin to understand the cognitive capacities of the evolutionary ancestors we share with these species. While there is a great deal of research exploring the socio-cognitive abilities of simian primates, prosimians have not been sufficiently studied. Without data from these species, our knowledge about the evolution of the primate mind is limited to the common ancestor shared between simian primates only, precluding understanding of the phylogenetic origins of certain phenomena. I explored the socio-cognitive capacities of lemurs, a type of prosimian primate. I studied several areas of social cognition related to social referencing, defined as the ability to use and seek out social information when appraising objects or events. As social referencing is a popular subject in both human developmental and non-human primate literature, I aimed to determine how prosimians’ capacities compare. My research was conducted with captive lemurs of three species: Eulemur fulvus fulvus, Eulemur macaco macaco, and Eulemur fulvus rufus. I found that lemurs use social cues regarding food palatability to modify their own feeding behaviour and that they visually attend to conspecifics differently when presented with novel, as compared to familiar, foods. Lemurs also visually referred to a human experimenter’s face when presented with an anomalous interaction and went on to engage in gaze alternation. Lemurs failed to use information about the experimenter’s attentional state, however, when modifying their use of a trained gesture. Finally, I found that lemurs are able to visually co-orient with conspecifics, correctly prioritising information from the head over that from the body, and that they go on to use conspecific gaze to locate hidden resources. These results show that lemurs are more cognitively advanced than previously thought and the origins of some social referencing skills may be phylogenetically older than previously hypothesised.
26

Roots of Primate Cognition. The Primate Cognition Test Battery applied to three species of lemurs (Varecia variegata, Lemur catta and Microcebus murinus).

Kittler, Klara 16 June 2017 (has links)
No description available.
27

Conservation physiology of two closely related, sympatric lemur species, the fat-tailed dwarf lemur (Cheirogaleus medius), and the gray mouse lemur (Microcebus murinus)

Rakotoniaina, Hasina Josué 04 November 2016 (has links)
No description available.
28

The role of acoustic and visual signals in species recognition in true lemurs (Eulemur: Primates)

Markolf Rakotonirina, Miadana Hanitriniaina 09 December 2016 (has links)
No description available.
29

Evolutionary mechanisms shaping MHC variation in sympatric lemurs

Kaesler, Eva 19 November 2015 (has links)
No description available.
30

Natural Resource Use in Madagascar

Reuter, Kim E. January 2015 (has links)
The anthropogenic use of natural resources has become a major cause of biodiversity loss and habitat degradation throughout the world. Deforestation - the conversion of forests to alternative land covers - has led to a decrease in local biodiversity directly through a decrease in habitat, and indirectly through habitat fragmentation. Likewise, defaunation – the loss of animals both directly through hunting and indirectly through deforestation – has led to the empty forest syndrome and subsequent deterioration of forest ecosystems. In many cases, areas where anthropogenic use of natural resources is high overlap with areas of high biodiversity value. Therefore, the present series of studies aims to better understand the impacts that different types of natural resources use and habitat degradation have on biodiversity. This dissertation details the results of five studies, which aimed to: 1) examine the effects of habitat degradation on plant-frugivore networks; 2), understand the live capture and extent of ownership of lemurs in Madagascar; 3) understand the micro- and macro-level drivers of wild meat consumption in Madagascar; 4) describe the capture, movement, and trade of wild meat in Madagascar; and 5) the impacts of habitat changes on the diets and vertical stratification of frugivorous bats. For the first study, our objectives were to understand the effects of habitat degradation on (1) community structure, (2) network structure, and (3) seed dispersal services. We focused on fruit-bearing trees and frugivores (two lemur and five bird species) across a three-point gradient of habitat degradation in a tropical dry forest in Madagascar. Our objectives were to understand the effects of habitat degradation on (1) community structure, (2) network structure, and (3) seed dispersal services. We focused on fruit-bearing trees and frugivores (two lemur and five bird species) across a three-point gradient of habitat degradation in a tropical dry forest in Madagascar. Data on fruit consumption by frugivores were collected over 592 hours of observations at 13 fruiting tree species. We found that as habitat became more degraded: (1) the community structure of both frugivores and fruiting tree communities changed; (2) the mutualistic network structure became less complex and less connected; (3) the interaction strengths of pair-wise interactions changed and the asymmetries of these interactions shifted; and (4) seed dispersal decreased by 91% in the secondary forest, compared to the primary forest. In addition, we show that frugivores: (1) sometimes stopped eating fruit in the degraded forest, even when they had consumed it in other forests; and (2) appeared to avoid some fruiting tree species while showing preference for others. The mutualistic network studied in this paper appeared sensitive to anthropogenic disturbance and a novel measure of effectiveness helped quantify these changes. For the second study, our objectives were to provide the first quantitative estimates of the prevalence, spatial extent, correlates and timing of lemur ownership, procurement methods, within-country movements, and numbers and duration of ownership. Using semi-structured interviews of 1,093 households and 61 transporters, across 17 study sites, we found that lemur ownership was widespread and affected a variety of taxa. We estimate that 28,253 lemurs have been affected since 2010. Most lemurs were caught by owners and kept for either short (≤1 week) or long (≥3 years) periods. The live capture of lemurs in Madagascar is not highly organized but may threaten several endangered species. For the third study, we investigated the role of wild meat in food security in Madagascar, a country where wild meat consumption is poorly understood in urban areas and at regional scales. Using semi-structured interviews (n = 1339 heads-of-households, 21 towns), we aimed to: 1) quantify the amount and purpose of; 2) understand the drivers behind; and, 3) examine recent changes in wild meat consumption in Madagascar. Few respondents preferred wild meat (8 ± 3%) but most had eaten it at least once (78 ± 7%), and consumption occurred across ethnic groups, in urban and rural settings. More food insecure areas reported higher rates of recent consumption of wild meat. However, consumption was best explained by individual preferences and taboos. Few respondents (&lt;1 ± &lt;1%) had increased rates of consumption during their lifetimes, and wild meat prices showed no change from 2005-2013. Most consumption involved wild pigs and small-bodied animals, though these animal groups and lemurs were consumed less in recent years. Given these data, wild meat is unlikely to enhance food security for most Malagasy people in urban and well-connected rural areas. For the fourth study, and to improve understanding of the wild meat trade in Madagascar, our objectives were to: (1) quantify the volume of consumption, transport, and sale for different animal groups, compared to domestic meat; (2) describe the methods of capture and hunting for different animal groups; (3) analyze the patterns of movement of wild meat from the capture location to the final consumer, compared to domestic meat; and (4) examine how the prices of wild meat change depending on the venue through which the consumer purchases it. Data was collected in May-August 2013 using semi-structured interviews of consumers (n = 1343 households, 21 towns), meatsellers (n = 520 restaurants, open-air markets stalls, and supermarkets, 9 towns), and drivers of inter-city transit vehicles (n = 61, 5 towns). We found that: (1) a wide range of hunting methods were used, though their prevalence of use differed by animal group; (2) wild meat traveled distances of up to 166 km to reach consumers, though some animal groups were hunted locally (&lt;10 km) in rural areas; (3) most wild meat was procured from free sources (hunting and receiving meat as a gift), though urban respondents who consumed bats and wild pigs were more likely to purchase those meats; and (4) wild meat was consumed at lower rates than domestic meat, though urban respondents consumed twice as much wild meat as rural respondents. We conclude that urban and rural respondents differ in how they interact with the wild meat commodity chain. We also believe that the consumption and trade of wild meat in Madagascar is likely more formalized that previously thought. Finally, for our fifth study, we used stable isotope analysis to examine how foraging by three fruit bat species in Madagascar, Pteropus rufus, Eidolon dupreanum, and Rousettus madagascariensis, are impacted by habitat change across a large spatial scale. Our results indicated that the three species had broadly overlapping diets. Differences in diet were nonetheless detectable and consistent between P. rufus and E. dupreanum, and these diets shifted when they co-occurred, suggesting resource partitioning across habitats and vertical strata within the canopy to avoid competition. Changes in diet were also correlated with a decrease in forest cover, though at a larger spatial scale in P. rufus than in E. dupreanum. These results suggest fruit bat species exhibit differing foraging strategies in response to habitat change. They also highlight the key threats that fruit bats face from habitat change, and clarify the spatial scales at which conservation efforts should be implemented to mitigate threats for these bat species in Madagascar. / Biology

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