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Causes and consequences of female competition in redfronted lemurs (Eulemur rufifrons)
Get PDFWeibliche Konkurrenz in Säugetieren scheint weitaus verbreiteter zu sein als ursprünglich angenommen und kann extreme Formen annehmen, einschließlich Ausschluss von Weibchen aus Gruppen und sogar Tod. Dennoch wurde weibliche Konkurrenz erst kürzlich als ein weit verbreiteter Mechanismus der sexuellen Selektion anerkannt und bleibt im Vergleich zum männlichen Wettbewerb wenig erforscht, sodass ihre Ursachen, Mechanismen und Konsequenzen vergleichsweise schlecht verstanden sind. Obwohl in den letzten Jahren vermehrt zu weiblicher Konkurrenz im Kontext der sexuellen Selektion geforscht wurde, untersuchen die meisten Studien die Muster weiblicher Konkurrenz isoliert von anderen Aspekten der Sozialität, wie den reproduktiven Interessen der Männchen oder nicht unter Berücksichtigung mehrerer Ursachen. Besonders seltene und wenig erforschte Mechanismen weiblicher Konkurrenz, wie der Ausschluss von Weibchen aus Gruppen, wurden bisher nur bei wenigen Arten untersucht.
In dieser Dissertation habe ich Ursachen und Konsequenzen weiblicher Konkurrenz bei Rotstirnmakis (Eulemur rufifrons) untersucht, einer Primatenart, die endemisch in Madagaskar vorkommt und bei der der Ausschluss von Weibchen aus Gruppen zuvor dokumentiert wurde. Mein Ziel war es, die demografischen Umstände, die weibliche Konkurrenz begünstigen, zu verstehen und Konfliktursachen, den Zusammenhang mit Verwandtenselektion und Interaktionen mit männlichen Fortpflanzungsstrategien zu untersuchen. Darüber hinaus habe ich potenzielle Konsequenzen von Ausschluss von Weibchen aus Gruppen für die sozialen Strukturen von Gruppen untersucht. Basierend auf 24 Jahren demografischer Daten und 6 Jahren Verhaltensbeobachtungen und Hormondaten bekannter Individuen zeige ich, dass weibliche Rotstirnmakis nahe Verwandte dauerhaft und gegen ihren Willen aus Gruppen ausschließen, mit vermutlich tödlichen Konsequenzen hat. Ich zeige, dass begrenzte Gruppengrößen die Hauptursache für das Ausscheiden von Individuen beider Geschlechter aus Gruppen ist und zeige, dass männliche Abwanderungen und weibliche Vertreibungen daher nicht unabhängig voneinander sind. Während weibliche Vertreibungen wahrscheinlicher waren, wenn mehr juvenile Weibchen anwesend waren, waren männliche Abwanderungen wahrscheinlicher, wenn der Anteil erwachsener Männchen zu erwachsenen Weibchen erhöht war. Darüber hinaus konnte ich zeigen, dass Überlebensraten von Jungtieren mit der Anzahl der vorhandenen juvenilen Weibchen abnahm. Ich konnte zeigen, dass trotz erhöhter Glukokortikoidspiegel, Aggressionsraten in beiden Geschlechtern nicht mit der Ressourcenverfügbarkeit oder der Fortpflanzungssaison zusammenhingen. Die Tatsache, dass weibliche Konkurrenz scheinbar nicht mit unmittelbarem Wettbewerb um Nahrungsressourcen oder den Zugang zu Fortpflanzungspartnern verbunden war, legt nahe, dass der Mechanismus vom Ausschluss von Weibchen aus Gruppen bei Rotstirnmakis eine evolutionär stabile Strategie sein könnte, die auf längerfristige Vorteile abzielt. Darüber hinaus schien die soziale Struktur von Gruppen durch den Verlust von Gruppenmitgliedern nicht beeinflusst zu werden.
Zusammenfassend bieten diese drei Kapitel ein umfassendes Bild eines extremen Falls des weiblichen Wettbewerbs. Sie unterstreichen die Bedeutung von integrativen Studien, die alle Gruppenmitglieder berücksichtigen, um ein vollständigeres Bild davon zu erhalten, was den weibliche Konkurrenz verursacht und wie sie die soziale Organisation einer Art formen kann. Darüber hinaus heben sie die Wichtigkeit langfristiger Studien hervor, um die Entdeckung und Quantifizierung sporadisch auftretender Mechanismen weiblicher Konkurrenz zu erleichtern.Competition among female mammals appears to be much more widespread than previously thought, and it can take on extreme forms, including eviction and even death. Nevertheless, female competition has only recently been acknowledged as a pervasive mechanism of sexual selection and it remains understudied in comparison to male competition, so that its causes, mechanisms, and consequences remain comparatively poorly understood. Although research on female competition in the light of sexual selection has been accumulating over the past years, most studies examine patterns of female competition isolated from other aspects of sociality such as reproductive interests of males or without consideration of multiple causes. Particularly rare and infrequent mechanisms of female competition such as female evictions have so far only been studied in a few species.
In this thesis, I studied causes and consequences of female competition in redfronted lemurs (Eulemur rufifrons), a primate species endemic to Madagascar where evictions have been previously documented. I aimed to understand demographic circumstances favouring female-female competition, causes of conflict, trade-offs with kin selection, and interactions with male reproductive strategies. In addition, I examined potential consequences of evictions on social structures of groups. Based on 24 years of demographic data and 6 years of behavioural observation and hormonal data of known individuals, I showed that female redfronted lemurs targeted close female kin for forcible, permanent, and presumably lethal eviction, even though groups contain multiple unrelated males. I identified limited group size as the main driver for departures of individuals of both sexes from groups and showed that male emigrations and female evictions are therefore not independent of each other. While female evictions were more likely at higher numbers of juvenile females, male emigrations were more likely when the proportion of adult males to adult females was increased. In addition, I found that infant survival decreased with number of juvenile females present. I could show that despite increased glucocorticoid levels, agonism levels in both sexes were not related to resource availability or reproductive season. The fact that female competition did not seem to be linked to immediate competition for food resources or access to mates, suggests that the mechanisms of female evictions in redfronted lemurs might be an evolutionary stable strategy that is aimed at longer-term benefits. Beyond this, the social structure of groups seemed to be unaffected by group member loss.
Together, these three chapters create a comprehensive portrait of an extreme case of female competition. They highlight the importance of conducting integrative studies that consider all group members to create a more complete picture of what causes competition in females and how it can form a species’ social organization. It further highlights the importance of long-term studies to facilitate the detection and quantification of sporadically occurring mechanisms of female competition.2024-04-2
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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