Sexual cannibalism facilitates genital damage in <Emphasis Type="Italic">Argiope lobata</Emphasis> (Araneae: Araneidae)

Sperm competition is a potent driving force in evolution leading to a remarkable variety of male adaptations that prevent or reduce fertilization by rivals. An extraordinary defensive strategy against sperm competition has evolved in a number of web spiders where males break off parts of their paired genitalia in order to obstruct the copulatory openings of females (mating plug). A recent comparative analysis on the family level reports that genital damage is most frequent in species with sexual cannibalism although, as yet, a functional association between sexual cannibalism and genital damage has not been found. Using the moderately sexually cannibalistic orb-web spider Argiope lobata, we show for the first time that males cannibalized during their first copulation damaged their pedipalps with significantly higher probability (74%) than males that escaped (15%). Of all males that damaged their genitalia, 44% were able to place a genital fragment inside the copulatory opening of the female, resulting in a relatively low total plugging rate of 14%. Successful obstruction of the female copulatory opening reduced the share of paternity of subsequent males (P ₂ = 0.06%), thus, indicating that genital damage may have evolved as a response to sperm competition in this species as well. However, the low incidence of successful plugging and the strong relationship between sexual cannibalism and genital damage suggest that apart from paternity protection, the nature of genital damage in A. lobata is further shaped by sexual conflict or cryptic female choice.     

Forests under the Southern Cross: The forest environmental frontier in Australia and New Zealand

Australia and New Zealand share many historical and contemporary commonalities. These define five contemporary forest environmental frontiers—for First Nations peoples, between agriculture and forestry, in forest management, in urban and peri-urban environments, and in relation to climate change. In both countries, the First Nations frontier is expanding in scale and significance with those peoples’ rights to land and forests. Frontiers with agriculture and in forest management are longstanding but dynamic and as yet little realised in relation to the need for forest and landscape restoration. Both countries are highly urbanised, elevating the significance of the urban and peri-urban frontier, particularly in the context of climate change. In both countries, forests will be profoundly impacted by climate change and are central to mitigation and adaptation strategies. Experience within and intersections between the frontiers offer encouraging prospects for synergies and for learning between the two countries and more widely.     

Patterns of courtship behavior and ejaculate characteristics in male red-winged blackbirds

Sperm competition in birds is likely to have important effects on the behavior and physiology of reproduction in both sexes. For males, such competition should select for large sperm reserves and behavioral adjustment of copulation when reserves are low. We investigated both these possibilities in free-living red-winged blackbirds (Agelaius phoeniceus), a highly polygynous species with apparently strong sperm competition. We found that the recent copulatory behavior of males did not affect the propensity to copulate with a model female. Ejaculates collected from individual males at 1-h intervals showed no evidence of sperm depletion, yet repeated ejaculates collected less than 10 min apart did. Male ejaculate size was significantly larger if it was the first one of the day (i.e., after an overnight rest). The average ejaculate size was 12.5 (±12.5 SD) million sperm. Males captured during the breeding season had an average of 111.7 (±52.8) million sperm stored in their seminal glomera. Because males average a peak copulation rate of six per female per day, in one day a male might utilize all the sperm in his seminal glomera if more than two females on his territory are fertilizable. We hypothesize that polygyny and sperm competition in this species have combined to select for rapid replenishment of the seminal glomera throughout the day, in contrast to other species that have been studied. Testis size and sperm reserves of male red-winged blackbirds are intermediate between monogamous species and species with intense sperm competition. Several possible explanations for this are discussed. Received: 21 October 1997 / Accepted after revision: 15 February 1998     

Regional Management of Farmland Feeding Geese Using an Ecological Prioritization Tool

Wild geese foraging on farmland cause increasing conflicts with agricultural interests, calling for a strategic approach to mitigation. In central Norway, conflicts between farmers and spring-staging pink-footed geese feeding on pastures have escalated. To alleviate the conflict, a scheme by which farmers are subsidized to allow geese to forage undisturbed was introduced. To guide allocation of subsidies, an ecological-based ranking of fields at a regional level was recommended and applied. Here we evaluate the scheme. On average, 40 % of subsidized fields were in the top 5 % of the ranking, and 80 % were within the top 20 %. Goose grazing pressure on subsidized pastures was 13 times higher compared to a stratified random selection of non-subsidized pastures, capturing 67 % of the pasture feeding geese despite that subsidized fields only comprised 13 % of the grassland area. Close dialogue between scientists and managers is regarded as a key to the success of the scheme.     

Changing household responses to drought in Tharaka, Kenya: vulnerability, persistence and challenge

Drought is a recurring challenge to the livelihoods of those living in Tharaka District, Kenya, situated in the semi-arid zone to the east of Mount Kenya, from the lowest slopes of the mountain to the banks of the Tana River. This part of Kenya has been marginal to the economic and political life of Kenya from the colonial period until the present day. A study of more than 30 years of change in how people in Tharaka cope with drought reveals resilience in the face of major macro-level transformations, which include privatisation of landownership, population growth, political decentralisation, increased conflict over natural resources, different market conditions, and environmental shifts. However, the study also shows troubling signs of increased use of drought responses that are incompatible with long-term agrarian livelihoods. Government policy needs to address the challenge of drought under these new macro conditions if sustainable human development is to be achieved.     

Socio-environmental conflict in the construction of a power plant in Spain's Basque Country: strategies,expertise and certifications

Social and anthropological studies show a growing number of conflicts surrounding energy projects, as governments and companies insist on their implementation despite the concerns of local actors about their perceived socio-environmental risks. In this context, the purpose of this paper is to analyse the politicisation of expertise and certifications in a conflict over the construction of a combined cycle power plant by linking strategic assumptions from two particular sociological approaches. The first approach is based on the study of frame alignment in social movement organisations and the second on the translating interests in actor–network theory. These linked premises are examined in the conflict arising from the construction of a combined cycle natural gas plant in Boroa, in the Basque Country of Spain. This case study brings to light interesting findings on the strategies of the different agencies, certifications, politicisation of expertise and the increasing hostility in local conflicts.     

Governing trade-offs in ecosystem services and disservices to achieve human–wildlife coexistence

Sustaining wildlife populations, which provide both ecosystem services and disservices, represents a worldwide conservation challenge. The ecosystem services and Ostrom's social–ecological systems frameworks have been adopted across natural and social sciences to characterize benefits from nature. Despite their generalizability, individually they do not include explicit tools for addressing the sustainable management of many wildlife populations. For instance, Ostrom's framework does not specifically address competing perspectives on wildlife, whereas the ecosystem services framework provides a limited representation of the social and governance context wherein such competing perspectives are embedded. We developed a unified social–ecological framework of ecosystem disservices and services (SEEDS) that advances both frameworks by explicitly acknowledging the importance of competing wildlife perspectives embedded in the social and governance contexts. The SEEDS framework emulates the hierarchical structure of Ostrom's social–ecological systems, but adds subsystems reflecting heterogeneous stakeholder views and experiences of wildlife-based services and disservices. To facilitate operationalizing SEEDS and further broader analyses across human–wildlife systems, we devised a list of variables to describe SEEDS subsystems, such as types and level of services and disservices, cost and benefit sharing, and social participation of stakeholders. Steps to implement SEEDS involve engaging local communities and stakeholders to define the subsystems, analyze interactions and outcomes, and identify leverage points and actions to remedy unwanted outcomes. These steps connect SEEDS with other existing approaches in social–ecological research and can guide analyses across systems or within individual systems to provide new insights and management options for sustainable human–wildlife coexistence.     

冲突分析在环境领域中的应用

冲突分析是用来分析冲突局势、预测冲突发展、研究、设计冲突处理方案的一门科学。本文根据国内外研究资料，分析了冲突分析在环境领域中的应用，其中对公共设施选址、污染集中治理投资的分摊、允许排污量在各排污口问的公平分配、水资源集中管理、协调度模型处理环境与经济的冲突、跨行政区河流边界水质标准的确定、资源的开发与保护等进行了重点评述，并指出了冲突分析理论中存在的问题、解决的办法和发展方向。     

Parent–offspring resource allocation in domestic pigs

Behavioural research on domestic pigs has included parent–offspring conflict, sibling competition, and the use of signals which influence resource allocation. In this paper, we review key sow–piglet behavioural studies and discuss their relevance to resource allocation theory. Sibling competition begins in the uterus and continues after birth, as piglets compete directly for access to the sow’s teats. This competition is made more severe by a unique dentition, which newborn piglets use to lacerate the faces of siblings during teat disputes. Competition often leads to the death of some littermates, especially those of low birth weight. Piglets also compete indirectly for milk, apparently by stimulating milk production at the teats that they habitually use at the expense of milk production by other teats. The complex nursing behavior of the sow appears designed to prevent the more vigorous piglets from monopolizing the milk. Sows give vocal signals which both attract piglets to suckle and synchronize their behavior during nursing episodes. Piglets give loud vocal signals when separated from the sow; calls which vary in intensity and appear to be honest signals of need. Udder massage by piglets may also serve as an honest signal of need. Parent–offspring conflict has been demonstrated experimentally in pigs. Specifically, when given the opportunity to control contact with their piglets, sows nurse less frequently, provide less milk, and lose less weight during lactation than sows that cannot control their level of contact. Because of this interesting natural history and because they are so amenable to experimentation, domestic pigs provide a rich system for testing ideas drawn from resource allocation theory. This contribution is part of the special issue “Sibling competition and cooperation in mammals” (guest editors: Robyn Hudson and Fritz Trillmich).     

生物质制燃油关键设备设计中的安全性研究

针对生物燃油生产过程中热载体复合加热装置中集气箱结构与热交换管的支撑问题可能带来的不安全因素,将创新设计方法学——TRIZ(发明问题解决理论)应用于加热装置的安全设计中,按照TRIZ解决问题的系统化方法,通过技术矛盾分析和创新原理应用解决存在的技术冲突,能有效地消除设备存在的不安全因素。在设备的安全设计中应用TRIZ理论,与传统方法相比能降低解决问题的难度,提高解决问题的效率,增强设备的安全可靠性,是一种值得推广的经济实用的创新方法。