1,721,058 research outputs found
Data from: Insulin signalling mediates the response to male-induced harm in female Drosophila melanogaster
No full textThis is the raw data for courtship and mating, egg and offspring production, survival and fitness calculations. The data is in Excel spreadsheets
Sex peptide receptor-regulated polyandry differentially modulates pre- and post-copulatory sexual selection in Drosophila
No full textData from Morimoto et al., Nature Communications paper
Condition, not eyespan, predicts contest outcome in female stalk-eyed flies, Teleopsis dalmanni
Full text linkIn contests among males, body condition is often the key determinant of a successful outcome, with fighting ability signaled by so-called armaments, that is, exaggerated, condition-dependent traits. However, it is not known whether condition and exaggerated traits function in the same way in females. Here, we manipulated adult condition by varying larval nutrition in the stalk-eyed fly, Teleopsis dalmanni, a species in which eyespan is exaggerated in both sexes, and we measured the outcome of contests between females of similar or different body condition and relative eyespan. We found that females in higher condition, with both larger bodies and eyespan, won a higher proportion of encounters when competing against rivals of lower condition. However, when females were of equal condition, neither eyespan nor body length had an effect on the outcome of a contest. An analysis of previously published data revealed a similar pattern in males: individuals with large relative eyespan did not win significantly more encounters when competing with individuals of a similar body size. Contrary to expectations, and to previous findings in males, there was no clear effect of differences in body size or eyespan affecting contest duration in females. Taken together, our findings suggest that although eyespan can provide an honest indicator of condition, large eyespans provide no additional benefit to either sex in intrasexual aggressive encounters; body size is instead the most important factor
'Hangry’ Drosophila: food deprivation increases male aggression - data
No full textI created the data from spot-check behavioural observations of the experimental organism. The code was used to analyse the data and runs in the software programme,
Polyandry and nutrition: key modulators of sexual selection in Drosophila melanogaster
Full text linkSexual selection is responsible for the evolution of formidable adaptations across the tree of life. Traditionally, sexual selection research has focused on male sexual displays and female choice. However, this approach ignores important social and environmental factors that can influence the operation of sexual selection. In this thesis, I aim to contribute to our knowledge of the effects of social and environmental factors, particularly those related to nutrition, on sexual selection. I investigate how the sexual behaviour of females and the nutritional and social environments of both sexes during larval and adult stages modulate sexual selection in the fruit fly Drosophila melanogaster.
First, I assess how female promiscuity ("polyandry") affects the strength of sexual selection and patterns of assortative mating in freely interacting populations. There is no current consensus for the conflicting results of previous studies showing that polyandry can have positive, negative or have negligible effect on the opportunity for sexual selection. Using a genetic knockout that increases female sexual receptivity, I show that increasing polyandry reduces the opportunity for sexual selection and shifts the relative role of sexual selection from pre- to post-copulatory in males without affecting assortative mating patterns in freely interacting populations.
Next, I consider how plastic responses to nutritionally poor larval environments and adult social environments modulate sexual selection, an area that has been considerably ignored. I find that although nutritionally poor larval environments reduce individuals' mating and reproductive success, plastic responses to social environments might mitigate against these disadvantages. Moreover, I show that plastic responses to larval and social environments influence the relative role of pre- and post-copulatory sexual selection in males, regulate offspring traits through trans-generational effects and determine population fate.
Finally, I consider whether male reproductive traits have distinct macronutrient (protein and carbohydrate) requirements, and whether males can regulate their feeding to attain a diet that satisfies the requirements for these traits. I find that both a high short-term rate of offspring production when males mate with virgin females, and a high total number of offspring sired when males mate with previously mated females, require carbohydrate-rich diets, whereas male attractiveness requires a balanced (1:1) macronutrient diet. Furthermore, I show that male protein intake can negatively affect female long-term reproduction when males mate with virgins, but not with previously mated females, revealing a novel intersexual effect of male nutrition.
Thus, this thesis deepens our understanding of key evolutionary processes by revealing the negative effects of high polyandry and nutritionally poor larval environments on the operation of sexual selection as well as uncovering male nutritional compromise in the expression of reproductive traits.</p
Family and familiarity in flies
Full text linkThe concept of gene-centred evolution and subsequent inclusive fitness theory provided a formal framework in which to study the adaptation of social behaviours. It highlighted the role of relatedness between individuals in mediating both cooperation and conflict. However, social behaviours can be difficult to study, particularly among animals in the wild. Drosophila melanogaster has been studied as a model organism for over a century, and we have a deep understanding of its genetics, development and physiology. Furthermore, its short lifespan, small size and fast reproduction rate make it an ideal laboratory animal. Yet we currently know very little about how relatedness affects social behaviours in this species. In this thesis, I aim to contribute to our knowledge of kin selection and recognition in Drosophila melanogaster, developing its use as a model organism for studying inclusive fitness.
In Chapter 2, I examine the role of relatedness on adult sexual behaviours, namely how male-male relatedness mediates sexual harm to females. I distinguish the roles of genetic relatedness and larval social familiarity, and find that familiarity alone is not sufficient and genetic relatedness is required to reduce sexual conflict. However, male intrasexual interactions are important, as in Chapter 3, I find no effect of relatedness when males are presented to the female sequentially rather than simultaneously.
In Chapters 4 and 5, I consider the effect of relatedness on larval social behaviours, which have thus far been understudied compared to their adult counterparts. Contrary to predictions from inclusive fitness theory, in Chapter 4 I find that larvae benefit from developing in unrelated, rather than related, groups. This is possibly due to the increased genetic diversity and therefore behavioural diversity in unrelated groups, reducing direct competition. In Chapter 5, I additionally show that larvae prefer to cannibalise unrelated and unfamiliar conspecific victims, which may have strong fitness consequences for both adult and larval behaviour.
This thesis provides new evidence that relatedness, over and above social familiarity, mediates both adult and larval behaviours in Drosophila melanogaster, allowing us further to develop this species as a model organism for kin selection.</p
'Hangry’ Drosophila: food deprivation increases male aggression - data 2021
No full textWe investigated the influence of food deprivation on aggression in male fruit flies, Drosophila melanogaster. The data file was created from spot check observation
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
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