Sexual Cannibalism: High Incidence in a Natural Population with Benefits to Females

10 pages, 3 figures.[Background] Sexual cannibalism may be a form of extreme sexual conflict in which females benefit more from feeding on males than mating with them, and males avoid aggressive, cannibalistic females in order to increase net fitness. A thorough understanding of the adaptive significance of sexual cannibalism is hindered by our ignorance of its prevalence in nature. Furthermore, there are serious doubts about the food value of males, probably because most studies that attempt to document benefits of sexual cannibalism to the female have been conducted in the laboratory with non-natural alternative prey. Thus, to understand more fully the ecology and evolution of sexual cannibalism, field experiments are needed to document the prevalence of sexual cannibalism and its benefits to females.[Methodology/Principal Findings] We conducted field experiments with the Mediterranean tarantula (Lycosa tarantula), a burrowing wolf spider, to address these issues. At natural rates of encounter with males, approximately a third of L. tarantula females cannibalized the male. The rate of sexual cannibalism increased with male availability, and females were more likely to kill and consume an approaching male if they had previously mated with another male. We show that females benefit from feeding on a male by breeding earlier, producing 30% more offspring per egg sac, and producing progeny of higher body condition. Offspring of sexually cannibalistic females dispersed earlier and were larger later in the season than spiderlings of non-cannibalistic females.[Conclusions/Significance] In nature a substantial fraction of female L. tarantula kill and consume approaching males instead of mating with them. This behaviour is more likely to occur if the female has mated previously. Cannibalistic females have higher rates of reproduction, and produce higher-quality offspring, than non-cannibalistic females. Our findings further suggest that female L. tarantula are nutrient-limited in nature and that males are high-quality prey. The results of these field experiments support the hypothesis that sexual cannibalism is adaptive to females.This paper has been written under a Ramón y Cajal research contract from the Spanish Ministry of Science and Technology (MCYT) to JML and an I3P-BPD2004-CSIC scholarship to RRB. This work has been funded by MEC grants CGL2004-03153 and CGL2007-60520 to JML, MARG, RRB, CFM and DHW.Peer reviewe

Identities and preferences in corporate political strategizing

This conceptual article draws on structuration theory and social identity theory to isolate firm-internal institutionalization processes as antecedents and drivers of corporate political strategizing. Path dependencies in corporate routines and actors' knowledgeability about these path dependencies are singled out as primary factors structuring strategic decision making within the firm. The concepts of path dependency and knowledgeability, respectively, refer to the institutional and cognitive dimension of corporate political strategizing. These two dimensions come together in actors' identities. Identities on their turn shape managers' recognition of policy issues and the interpretation of issue salience relative to corporate interests. Thus, the article argues that institutional features of competitive environments precipitate in processes of identity building and preference formation and are reproduced through organizational routines and practices within the firm. © 2006 Sage Publications

Executive Agencies, Ministers, and Departments: Can Policy and Management Ever be Separated?

The creation of executive agencies outside core departments has been a major element of administrative reforms throughout Europe during the past two decades, driven by a managerial logic, which also has been at the core of most academic works on "agencification." In this article, the authors take a different perspective by focusing on executive agencies' influence in the policy process. The authors analyze the policy influence of a large executive agency with service delivery tasks in the context of a parliamentary system of government (Flanders, Belgium). A comparison of the agency's influence in two major policy processes shows that a complex interplay of policy content, patterns of interaction, and mutual trust with the political leadership and organizational characteristics helps in explaining the observed patterns of influence. The findings also raise normative concerns regarding potential problems of disconnecting operations from policy formulation via agencification. © 2012 SAGE Publications

Negative incentive steering in a policy network

In this article the process of developing a policy for the recent comprehensive retrenchment operation in the Dutch university system is analysed from a theoretical point of view on decisionmaking. The article especially addresses the question whether some empirical evidence can be found for the rationalist view of collective decision-making, which states that a process of social communication should eventually lead to a unanimous and rational consensus concerning the selection of the optimal policy.\ud \ud The actual analysis concerns the way a retrenchment policy has been developed in a process of social communication between the most important actors: the Minister of Education and Science and the thirteen Dutch universities. It is assumed that the various communicative linkages between these actors can be interpreted as a policy network in which both governmental and non-governmental actors operate.\ud \ud The article concludes that in the Dutch university policy-network a complicated balance of interdependencies exists and that several sub-networks can be distinguished. It is also concluded that the Minister, while recognizing the interdependencies in the network, was able to use a special kind of (negative) incentive, inducing the universities to act as he wished.\ud \ud This negative incentive steering, however, also persuaded the universities to go to the utmost in their consultation efforts, thus trying to reach the rationalist ideal of collective decision-making. The final conclusion therefore is that the rationalist view of collective decision-making does not appear to be unrealistic. The article ends with a warning against a common mistake made regarding the normative appearance of the rationalist perspective

Beyond the public and private divide: Remapping transnational climate governance in de 21th century

This article provides a first step towards a better theoretical and empirical knowledge of the emerging arena of transnational climate governance. The need for such a re-conceptualization emerges from the increasing relevance of non-state and transnational approaches towards climate change mitigation at a time when the intergovernmental negotiation process has to overcome substantial stalemate and the international arena becomes increasingly fragmented. Based on a brief discussion of the increasing trend towards transnationalization and functional segmentation of the global climate governance arena, we argue that a remapping of climate governance is necessary and needs to take into account different spheres of authority beyond the public and international. Hence, we provide a brief analysis of how the public/private divide has been conceptualized in Political Science and International Relations. Subsequently, we analyse the emerging transnational climate governance arena. Analytically, we distinguish between different manifestations of transnational climate governance on a continuum ranging from delegated and shared public-private authority to fully non-state and private responses to the climate problem. We suggest that our remapping exercise presented in this article can be a useful starting point for future research on the role and relevance of transnational approaches to the global climate crisis

Trophic Shifts of a Generalist Consumer in Response to Resource Pulses

Trophic shifts of generalist consumers can have broad food-web and biodiversity consequences through altered trophic flows and vertical diversity. Previous studies have used trophic shifts as indicators of food-web responses to perturbations, such as species invasion, and spatial or temporal subsidies. Resource pulses, as a form of temporal subsidies, have been found to be quite common among various ecosystems, affecting organisms at multiple trophic levels. Although diet switching of generalist consumers in response to resource pulses is well documented, few studies have examined if the switch involves trophic shifts, and if so, the directions and magnitudes of the shifts. In this study, we used stable carbon and nitrogen isotopes with a Bayesian multi-source mixing model to estimate proportional contributions of three trophic groups (i.e. producer, consumer, and fungus-detritivore) to the diets of the White-footed mouse (Peromyscus leucopus) receiving an artificial seed pulse or a naturally-occurring cicadas pulse. Our results demonstrated that resource pulses can drive trophic shifts in the mice. Specifically, the producer contribution to the mouse diets was increased by 32% with the seed pulse at both sites examined. The consumer contribution to the mouse diets was also increased by 29% with the cicadas pulse in one of the two grids examined. However, the pattern was reversed in the second grid, with a 13% decrease in the consumer contribution with the cicadas pulse. These findings suggest that generalist consumers may play different functional roles in food webs under perturbations of resource pulses. This study provides one of the few highly quantitative descriptions on dietary and trophic shifts of a key consumer in forest food webs, which may help future studies to form specific predictions on changes in trophic interactions following resource pulses

OVERHEATED SECURITY? The Securitisation of Climate Change and the Governmentalisation of Security

Since the mid-2000s, climate change has become one of the defining security issues in political as well as academic debates and amongst others has repeatedly been discussed in the UN Security Council and countless high level government reports in various countries. Beyond the question whether the characterisation as ‘security issue’ is backed up by any robust empirical findings, this begs the question whether the ‘securitisation’ of climate change itself has had tangible political consequences. Moreover, within this research area there is still a lively discussion about which security conceptions apply, how to conceptualise (successful) securitisation and whether it is a (politically and normatively) desirable approach to deal with climate change. The aim of this dissertation is to shed light on these issues and particularly to contribute to a more thorough understanding of different forms or ‘discourses’ of securitisation and their political effects on a theoretical and empirical level. Theoretically, it conceptualises securitisation as resting on different forms of power, which are derived from Michel Foucault’s governmentality lectures. The main argument is that this framework allows me to better capture the ambiguous and diverse variants of securitisation and the ever-changing concept of security as well as to come to a more thorough understanding of the political consequences and powerful effects of constructing issues in terms of security. Empirically, the thesis looks at three country cases, namely the United States, Germany and Mexico. This comparative angle allows me to go beyond the existing literature on the securitisation of climate change that mostly looks at the global level, and to come to a more comprehensive and detailed understanding of different climate security discourses and their political consequences. Concerning the main results, the thesis finds that climate change has indeed been securitised very differently in the three countries and thus has facilitated diverse political consequences. These range from an incorporation of climate change into the defence sector in the US, the legitimisation of far-reaching climate policies in Germany, to the integration of climate change into several civil protection and agricultural insurance schemes in Mexico. Moreover, resting on different forms of power, the securitisation of climate change has played a key role in constructing specific actors and forms of knowledge as legitimate as well as in shaping certain identities in the face of the dangers of climate change. From a normative perspective, neither of these political consequences is purely good or bad but highly ambiguous and necessitates a careful, contextual assessment

Constraints on Energy Intake in Fish: The Link between Diet Composition, Energy Metabolism, and Energy Intake in Rainbow Trout

The hypothesis was tested that fish fed to satiation with iso-energetic diets differing in macronutrient composition will have different digestible energy intakes (DEI) but similar total heat production. Four iso-energetic diets (2×2 factorial design) were formulated having a contrast in i) the ratio of protein to energy (P/E): high (HP/E) vs. low (LP/E) and ii) the type of non-protein energy (NPE) source: fat vs. carbohydrate which were iso-energetically exchanged. Triplicate groups (35 fish/tank) of rainbow trout were hand-fed each diet twice daily to satiation for 6 weeks under non-limiting water oxygen conditions. Feed intake (FI), DEI (kJ kg−0.8 d−1) and growth (g kg−0.8 d−1) of trout were affected by the interaction between P/E ratio and NPE source of the diet (P<0.05). Regardless of dietary P/E ratio, the inclusion of carbohydrate compared to fat as main NPE source reduced DEI and growth of trout by ∼20%. The diet-induced differences in FI and DEI show that trout did not compensate for the dietary differences in digestible energy or digestible protein contents. Further, changes in body fat store and plasma glucose did not seem to exert a homeostatic feedback control on DEI. Independent of the diet composition, heat production of trout did not differ (P>0.05). Our data suggest that the control of DEI in trout might be a function of heat production, which in turn might reflect a physiological limit related with oxidative metabolism