Habitat fragmentation, ecology and sexual selection in forest bird species in Monteverde, Costa Rica

Abstract Forest fragmentation is often associated with local extinction and changes in species abundance patterns. The main topic of this thesis is the effect of forest fragmentation on birds in Monteverde, Costa Rica. This thesis also studies aspects of sexual selection and ecology of Long-tailed Manakins, Chiroxiphia Linearis. Chapter 1 investigates bird species assemblages in two degrees of forest fragmentation. It is shown that the distribution, abundance and diversity of forest bird species are strongly influenced by the amount of forest in the landscape matrix. Presence of cattle within the forest influences the presence of some bird species. The prevalence and intensity of ticks and blood parasites on birds in relation to fragmentation is described in Chapter 2. Overall tick prevalence is 3%. Understory birds are significantly more infested with ticks than species at intermediate heights. Tick prevalence on birds does not differ significantly between two degrees of forest fragmentation and individual tick loads tend to be higher in High- than in Low-fragmentation sites. Infestations by the blood parasites Haemoproteus sp. was low except in white-eared ground sparrow, Melozone leucotis, that is 28% and is significantly higher in High- than in Low-fragmentation sites. In chapter 3 results on the ecology and habitat movements of the Bare-necked Umbrellabird, Cephalopterus glabricollis, are presented. The abundance of umbrellabirds at high elevations during the breeding season coincides with the highest peak of fruit abundance. Birds leave the protected area during the non-breeding season moving to unprotected forest fragments. In chapter 4 ontogenetic changes in feather morphology through sexual maturity in Long-tailed Manakins are described. In adult males, rectrices length is positively correlated to testis volume. Changes in male morphology during ontogeny in the long-tailed manakin appear to be associated with their specific-display behaviours. Significant interpopulation differences in the morphology of Long-tailed Manakins are shown in chapter 5. These differences are more accentuated in morphological traits related to flight displays. A field experiment demonstrates that long rectrices impose flying costs for males and females. A reduction in flying ability was found to be strongest in males from a population presenting the highest degree of sexual dimorphism. Résumé La fragmentation des forêts est souvent associée avec des modifications dans l'abondance des espèces et des extinctions locales. Le thème principale de cette thèse est l'étude de l'effet de la fragmentation des forêts sur les oiseaux de Monteverde, Costa Rica. Elle décrit par ailleurs certains aspects de la sélection sexuelle et l'écologie du manakin à longue queue, Chiroxiphia linearis. Dans le Chapitre 1 je montre que la distribution, l'abondance et la diversité des assemblages d'oiseaux vivant dans la forêt sont fortement influencées pas le degré de fragmentation de celle ci. Par ailleurs, la présence ou l'absence de bétail dans les forêts influence la présence de certaines espèces d'oiseaux. Dans le chapitre 2 j'ai étudié la prévalence et l'intensité d'infestation par des tiques ainsi que la présence de parasites sanguins chez les oiseaux en relation avec la fragmentation des forêts. La prévalence globale de tiques est de 3 %, les oiseaux vivant au niveau du sol étaient plus souvent infectés par des tiques que les espèces se déplaçant à un niveau plus élevé. La prévalence de tiques sur les oiseaux n'était pas significativement différente entre les paysages avec différentes fragmentations. Les parasites sanguins du genre Haemoproteus sp. étaient présents à très basse fréquence à l'exception chez Melozone leucotis ou la prevalence était de 28% et significativement plus élevée chez les oiseaux vivant dans les forêts à forte fragmentation. Dans le Chapitre 3 je présente des résultats sur l'écologie et les mouvements entre habitats chez le "Bare-necked umbrellabird", Cephalopterus glabricollis. Cette espèce endémique du Costa Rica niche à haute altitude durant la période d'abondance des fruits et réalise une migration altitudinale vers des zones basses durant la saison de non reproduction. Dans le chapitre 4 je présente les changements ontogénétiques dans la morphologie du plumage des manakins à longue queue. Chez les mâles, les changements de morphologie semblent être associés avec leurs comportements de parade spécifiques. Dans le chapitre 5 je présente des différences morphologiques significative entre deux populations chez le manakin à longue queue et je montre que la capacité de vols chez les mâles est plus fortement influencée dans la population avec le degré de dimorphisme sexuel le plus prononcé.

Independent contribution of parental migrant status and educational level to adiposity and eating habits in preschool children.

Background/Objective:Little is known about the precise role of parental migrant status (MS) and educational level (EL) on adiposity and various eating habits in young children. Therefore, we assessed their independent contribution in preschoolers.Subjects/Methods:Of 655 randomly selected preschoolers, 542 (5.1±0.6 years; 71% of parental MS and 37% of low parental EL) were analysed. Body composition was measured by bioelectrical impedance. Eating habits were assessed using a semiqualitative food frequency questionnaire and analysed according to five messages developed by the Swiss Society for Nutrition, based on factors implicated in childhood obesity: (1) 'Drinking water and decreasing sweetened drinks', (2) 'Eating fruit and vegetables', (3) 'Decreasing breakfast skipping', (4) 'Reducing fatty and sweet foods' and (5) 'Reducing the intake of meals and snacks in front of television'.Results:Children of migrant and low EL parents had higher body fat, ate more meals and snacks while watching television and had more fruit and fatty foods compared with their respective counterparts (all P0.04). Children of low EL parents also consumed less water and vegetables compared with their counterparts (all P0.04). In most instances, we found an independent contribution of parental MS and EL to adiposity and eating habits. A more pronounced effect was found if both parents were migrants or of low EL. Differences in adiposity and eating habits were relatively similar to the joint parental data when assessed individually for maternal and paternal MS and EL.Conclusions:Parental MS and EL are independently related to adiposity and various eating habits in preschoolers.European Journal of Clinical Nutrition advance online publication, 3 November 2010; doi:10.1038/ejcn.2010.248.

Binge eating in binge eating disorder: a break-down of emotion regulatory process?

Current explanatory models for binge eating in binge eating disorder (BED) mostly rely onmodels for bulimianervosa (BN), although research indicates different antecedents for binge eating in BED. This studyinvestigates antecedents and maintaining factors in terms of positive mood, negative mood and tension in asample of 22 women with BED using ecological momentary assessment over a 1-week. Values for negativemood were higher and those for positive mood lower during binge days compared with non-binge days.During binge days, negative mood and tension both strongly and significantly increased and positive moodstrongly and significantly decreased at the first binge episode, followed by a slight though significant, andlonger lasting decrease (negative mood, tension) or increase (positive mood) during a 4-h observation periodfollowing binge eating. Binge eating in BED seems to be triggered by an immediate breakdown of emotionregulation. There are no indications of an accumulation of negative mood triggering binge eating followed byimmediate reinforcing mechanisms in terms of substantial and stable improvement of mood as observed inBN. These differences implicate a further specification of etiological models and could serve as a basis fordeveloping new treatment approaches for BED.

Controversies about a common etiology for eating and mood disorders.

Obesity and depression represent a growing health concern worldwide. For many years, basic science and medicine have considered obesity as a metabolic illness, while depression was classified a psychiatric disorder. Despite accumulating evidence suggesting that obesity and depression may share commonalities, the causal link between eating and mood disorders remains to be fully understood. This etiology is highly complex, consisting of multiple environmental and genetic risk factors that interact with each other. In this review, we sought to summarize the preclinical and clinical evidence supporting a common etiology for eating and mood disorders, with a particular emphasis on signaling pathways involved in the maintenance of energy balance and mood stability, among which orexigenic and anorexigenic neuropeptides, metabolic factors, stress responsive hormones, cytokines, and neurotrophic factors.

Shots de fruits et légumes : avantages et inconvénients [Fruit and vegetable beverages: advantages and disadvantages]

En Suisse, les recommandations de fruits et légumes sont de 600 g par jour. En réalité, la consommation moyenne se situe à 60% des recommandations, c'est-à-dire à 380 g par jour. L'utilisation de produits tels que des shots de fruits et légumes pourrait réduire l'écart en facilitant la consommation de ces aliments. Cependant, ils ne peuvent pas remplacer à cent pour cent les aliments frais car leurs teneurs en fibres et vitamines C sont plus faibles, et ils interfèrent avec la physiologie de la prise alimentaire (satiété). Ces produits peuvent donc faire partie d'une alimentation variée en prenant la place d'une portion de fruits et légumes. Un autre aspect non négligeable en est le coût puisque si l'on consommait ces produits sur une semaine à la place d'aliments frais la différence serait d'environ CHF 30.- de plus. In Switzerland, fruits and vegetables recommendations are of 600 gr per day. In reality, the average intake is about 60% of these recommendations, it means 380 gr per day. The use of products like fruits and vegetables shots could reduce the gap by making drinking easier. However, they cannot replace one hundred percent fresh food for their content in fibers and vitamin C are lower and they interfere with the physiology of the food intake (satiety). These products can have their importance in a various supply by taking the place of one fruit or vegetable portion. Another non negligible aspect is the price as if we consume these products over one week instead of fresh food, the difference would be of about CHF 30.- more

Niche conservatism in non-native birds in Europe: niche unfilling rather than niche expansion

Aim Niche conservatism, or the extent to which niches are conserved across space and time, is of special concern for the study of non-native species as it underlies predictions of invasion risk. Based on the occurrence of 28 non-native birds in Europe, we assess to what extent Grinnellian realized niches are conserved during invasion, formulate hypotheses to explain the variation in observed niche changes and test how well species distribution models can predict non-native bird occurrence in Europe. Location Europe. Methods To quantify niche changes, a recent method that applies kernel smoothers to densities of species occurrence in a gridded environmental space was used. This corrects for differences in the availability of environments between study areas and allows discrimination between 'niche expansion' into environments new to the species and 'niche unfilling', whereby the species only partially fills its niche in the invaded range. Predictions of non-native bird distribution in Europe were generated using several distribution modelling techniques. Results Niche overlap between native and non-native bird populations is low, but niche changes are smaller for species having a higher propagule pressure and that were introduced longer ago. Non-native birds in Europe occupy a subset of the environments they inhabit in their native ranges. Niche expansion into novel environments is rare for most species, allowing species distribution models to accurately predict invasion risk. Main conclusions Because of the recent nature of most bird introductions, species occupy only part of the suitable environments available in the invaded range. This signals that apart from purely ecological factors, patterns of niche conservatism may also be contingent on population-specific historical factors. These results also suggest that many claims of niche differences may be due to a partial filling of the native niche in the invaded range and thus do not represent true niche changes.

Eumelanin-based coloration and fitness parameters in birds: a meta-analysis

Although melanin is the most common pigment in animal integuments, the adaptive function of variation in melanin-based coloration remains poorly understood. The individual fitness returns associated with melanin pigments can be variable across species as these pigments can have physical and biological protective properties and genes involved in melanogenesis may vary in the intensity of pleiotropic effects. Moreover, dark and pale coloration can also enhance camouflage in alternative habitats and melanin-based coloration can be involved in social interactions. We investigated whether darker or paler individuals achieve a higher fitness in birds, a taxon wherein associations between melanin-based coloration and fitness parameters have been studied in a large number of species. A meta-analysis showed that the degree of melanin-based coloration was not significantly associated with laying date, clutch size, brood size, and survival across 26 species. Similar results were found when restricting the analyses to non-sexually dimorphic birds, colour polymorphic and monomorphic species, in passerines and non-passerines and in species for which inter-individual variation in melanism is due to colour intensity. However, eumelanic coloration was positively associated with clutch and brood size in sexually dimorphic species and those that vary in the size of black patches, respectively. Given that greater extent of melanin-based coloration was positively associated with reproductive parameters and survival in some species but negatively in other species, we conclude that in birds the sign and magnitude of selection exerted on melanin-based coloration is species- or trait-specific.

Former eating disorder impairs 3rd person but not 1st person perspective taking. Does dance training help?

The mental ability to take the perspective of another person may depend on one's own bodily awareness and experience. In the present study, the former was defined as having a history of an eating disorder, and the latter variable was defined as formal experience with dance. The study used a 2 × 2 × 2 factorial design in which reaction times in two mental perspective taking tasks were compared between female dancers and non-dancers with and without a former eating disorder. Participants were asked to imagine two perspectives: i) the position of front-facing and back-facing figures (3rd person perspective taking task) and ii) that these same figures are a self reflection in a mirror (1st person perspective taking task). In both tasks, a particular hand was indicated in the presented figures, and the participants had to decide whether the hand represented their own left or right hand. Overall, responses were slower for front-facing than back-facing figures in the 3rd person perspective taking task, and for back-facing than front-facing figures in the 1st person perspective taking task. Importantly, having a former history of an eating disorder related to a decreased performance in the 3rd person perspective taking task, but only in participants without dance experience. Results from an additional control group (a history of exercise but no dance experience) indicated that dance is particularly beneficial for mental bodily perspective taking. Dance experience, more so than exercise in general, can benefit 3rd person or extrapersonal perspective taking, supporting the favourable impact this exercise has on own body processing

Evolutionary ecology of learning: insights from fruit flies

Ecologically and evolutionarily oriented research on learning has traditionally been carried out on vertebrates and bees. While less sophisticated than those animals, fruit flies (Drosophila) are capable of several forms of learning, and have an advantage of a short generation time, which makes them an ideal system for experimental evolution studies. This review summarizes the insights into evolutionary questions about learning gained in the last decade from evolutionary experiments on Drosophila. These experiments demonstrate that Drosophila have the genetic potential to evolve substantially improved learning performance in ecologically relevant learning tasks. In at least one set of selected populations the improved learning generalized to another task than that used to impose selection, involving a different behavior, different stimuli, and a different sensory channel for the aversive reinforcement. This improvement in learning ability was associated with reduction in other fitness-related traits, such as larval competitive ability and lifespan, pointing out to evolutionary trade-offs of improved learning. These trade-offs were confirmed by other evolutionary experiments where reduction in learning performance was observed as a correlated response to selection for tolerance to larval nutritional stress or for delayed aging. Such trade-offs could be one reason why fruit flies have not fully used up their evolutionary potential for learning ability. Finally, another evolutionary experiment with Drosophila provided the first direct evidence for the long-standing ideas that learning can under some circumstances accelerate and in other slow down genetically-based evolutionary change. These results demonstrate the usefulness of fruit flies as a model system to address evolutionary questions about learning.

Avian erythrocytes have functional mitochondria, opening novel perspectives for birds as animal models in the study of ageing.

BACKGROUND: In contrast to mammalian erythrocytes, which have lost their nucleus and mitochondria during maturation, the erythrocytes of almost all other vertebrate species are nucleated throughout their lifespan. Little research has been done however to test for the presence and functionality of mitochondria in these cells, especially for birds. Here, we investigated those two points in erythrocytes of one common avian model: the zebra finch (Taeniopygia guttata). RESULTS: Transmission electron microscopy showed the presence of mitochondria in erythrocytes of this small passerine bird, especially after removal of haemoglobin interferences. High-resolution respirometry revealed increased or decreased rates of oxygen consumption by erythrocytes in response to the addition of respiratory chain substrates or inhibitors, respectively. Fluorometric assays confirmed the production of mitochondrial superoxide by avian erythrocytes. Interestingly, measurements of plasmatic oxidative markers indicated lower oxidative stress in blood of the zebra finch compared to a size-matched mammalian model, the mouse. CONCLUSIONS: Altogether, those findings demonstrate that avian erythrocytes possess functional mitochondria in terms of respiratory activities and reactive oxygen species (ROS) production. Interestingly, since blood oxidative stress was lower for our avian model compared to a size-matched mammalian, our results also challenge the idea that mitochondrial ROS production could have been one actor leading to this loss during the course of evolution. Opportunities to assess mitochondrial functioning in avian erythrocytes open new perspectives in the use of birds as models for longitudinal studies of ageing via lifelong blood sampling of the same subjects.

Having Your Cake and Eating It, Too: Can Regulatory Agencies Be Both Independent and Accountable?

Independent regulatory agencies (IRAs) were created in various sectors and on different governmental levels to implement liberalization policies. This paper investigates the link between IRAs' independence, which is said to promote regulatory credibility and the use of technical expertise, and their accountability, which is related to the need for controlling and legitimizing independent regulators. The literature on the regulatory state anticipates a positive relation between the independence and accountability of IRAs, but systematic empirical evidence is still lacking. To tackle this question, this paper measures and compares the independence and the accountability of IRAs in three differentially liberalized sectors in Switzerland (telecommunications, electricity and railways). With the application of Social Network Analysis, this piece of research shows that IRAs can be de facto independent and accountable at the same time, but the two features do not necessarily co-evolve in the same direction.

Strategies of emotion regulation in adolescents and young adults with substance dependence or eating disorders

Some authors argue that both substance dependence and eating disorders should be considered as dependent behaviours. Similarities and differences between these disorders, however, remain unclear. This study compares processes of emotion regulation in adolescents and young adults (15 to 25 years old) with substance dependence (SD) or eating disorders (ED). One hundred and thirteen SD, 50 ED and 86 non-clinical subjects (NC), recruited in four French and Swiss locations, completed a self-report questionnaire of emotion regulation strategies. This questionnaire addresses the subjects' relationships, concerning past and present family, and refers to Main's (1990) concept of primary strategy (balanced activation and deactivation of attachment behaviours), and of secondary strategies (hyperactivation or excessive deactivation of the attachment system). Participants were also questioned in structured interviews, about life events and DSM-IV classification criteria. SD reported more adverse events than ED and NC. SD and ED reported using fewer primary strategies than NC, and SD had secondary strategies that were different from those of ED. Patients with eating disorders reported more hyperactivation, and SD reported more deactivation of the attachment system. It is hypothesized that while subjects with SD and ED have in common poorly regulated strategies, they differ in the way they process emotion or relationship-related information.