Fighting behaviour as a correlate of male mating success in black grouse Tetrao tetrix

Fighting is a fundamental determinant of male fitness in species where females prefer socially dominant males as mates or where dominants can prevent subordinates from mating. This in turn can lead to the evolution of honest inter- and intra-sexual cues of male dominance. Fighting as a behaviour comprises both fighting rate (number of fights per unit of time) and fighting performance (success in winning fights), but it is not always clear which of these components are important for female choice and how they link to signals of male quality. To quantify the relative importance of fighting as a cue for females, we recorded detailed behavioural data from male black grouse Tetrao tetrix at leks. We explored the relationship between phenotypic traits (body mass, eye comb size, tail (lyre) length and blue chroma colouration) and fighting performance and rates and how these were related to male mating success. In older males' pairwise fights, winners had lower blue chroma than losers, but there were no differences in other morphological traits. In yearlings, no morphological trait predicted success in pairwise contests. Both fighting rate and performance were positively related to the number of copulations acquired by a male; however, when controlled for lek centrality, fighting performance and not fighting rate was significantly related to mating success. Our results indicate that females may be using components of fighting behaviour as cues for mate choice.     

Exploring the effects of individual traits and within-colony variation on task differentiation and collective behavior in a desert social spider

Social animals are extraordinarily diverse and ecologically abundant. In understanding the success of complex animal societies, task differentiation has been identified as a central mechanism underlying the emergence and performance of adaptive collective behaviors. In this study, we explore how individual differences in behavior and body size determine task allocation in the social spider Stegodyphus dumicola. We found that individuals with high body condition indices were less likely to participate in prey capture, and individuals’ tendency to engage in prey capture was not associated with either their behavioral traits or body size. No traits were associated with individuals’ propensity to participation in web repair, but small individuals were more likely to engage in standard web-building. We also discovered consistent, differences among colonies in their collective behavior (i.e., colony-level personality). At the colony level, within-colony variation in behavior (aggressiveness) and body size were positively associated with aggressive foraging behavior. Together, our findings reveal a subtly complex relationship between individual variation and collective behavior in this species. We close by comparing the relationship between individual variation and social organization in nine species of social spider. We conclude that intraspecific variation is a major force behind the social organization of multiple independently derived lineages of social spider.     

Species-specific influence of group composition on collective behaviors in ants

The success of a social group is often driven by its collective characteristics and the traits of its individuals. Thus, understanding how collective behavior is influenced by the behavioral composition of group members is an important first step to understand the ecology of collective personalities. Here, we investigated how the efficiency of several group behaviors is influenced by the aggressiveness of its members in two species of Temnothorax ants. In our manipulation of group composition, we created two experimentally reconstituted groups in a split-colony design, i.e., each colony was split into an aggressive and a docile group of equal sizes. We found strong species-specific differences in how collective behaviors were influenced by its group members. In Temnothorax longispinosus, having more aggressive individuals improved colony defense and nest relocation efficiency. In addition, source colony identity strongly influenced group behavior in T. longispinosus, highlighting that manipulations of group compositions must control for the origin of the chosen individuals. In contrast, group composition and source colony did not influence collective behaviors in Temnothorax curvispinosus. This suggests that the mechanisms regulating collective behaviors via individual differences in behavior might differ among even closely related species.     

The short-run impact of environmental protection costs on U.S. product prices

Using an input-output framework, this paper investigates the magnitude of the impact that environmental protection costs had on prices in the United States in 1977. With the imposition of environmental protection costs, the projected total price increases for individual industries range from 0.12% to 6.58%. Due to data limitations, the constraints of input-output analysis, and the structural changes that occurred in the economy from 1972 to 1977, the results should not be taken as definitive. However, the results do indicate the typical sort of variation in impact likely to occur across industries and that the average impact on prices was modest.     

Adsorption and clay-catalyzed degradation of erythromycin A on homoionic clays

Erythromycin has been widely used in food-producing animals and in humans, and is frequently detected as an organic pollutant in U.S. streams. In batch experiments with homoionic clays, the Freundlich isotherms were determined at 10 and 25 degrees C. The adsorption of erythromycin A was strongly influenced by clay type, exchanged cations, the pH of the bulk solutions, and the acidity of clay surfaces. The formation of clay-erythromycin A complexes was thermodynamically favorable except for K+- and Fe3+-exchanged montmorillonites, since the reactions were exothermic (deltaH(o) > 0) and the systems became stable (deltaS(o) > 0). Clays catalyzed the erythromycin A degradation by the hydrolysis of the neutral sugar and the multiple dehydrations. The surface acidity of clay surface enhanced the rate of clay-catalyzed degradation of erythromycin A. In addition, the Fe3+-exchanged clay minerals seemed to have an electrostatic interaction with the erythromycin A molecule, by which the hydrolysis of the neutral sugar was influenced.     

Resilience and sustainable development: building adaptive capacity in a world of transformations

Emerging recognition of two fundamental errors underpinning past polices for natural resource issues heralds awareness of the need for a worldwide fundamental change in thinking and in practice of environmental management. The first error has been an implicit assumption that ecosystem responses to human use are linear, predictable and controllable. The second has been an assumption that human and natural systems can be treated independently. However, evidence that has been accumulating in diverse regions all over the world suggests that natural and social systems behave in nonlinear ways, exhibit marked thresholds in their dynamics, and that social-ecological systems act as strongly coupled, complex and evolving integrated systems. This article is a summary of a report prepared on behalf of the Environmental Advisory Council to the Swedish Government, as input to the process of the World Summit on Sustainable Development (WSSD) in Johannesburg, South Africa in 26 August 4 September 2002. We use the concept of resilience--the capacity to buffer change, learn and develop--as a framework for understanding how to sustain and enhance adaptive capacity in a complex world of rapid transformations. Two useful tools for resilience-building in social-ecological systems are structured scenarios and active adaptive management. These tools require and facilitate a social context with flexible and open institutions and multi-level governance systems that allow for learning and increase adaptive capacity without foreclosing future development options.     

Geographic information systems and environmental impact assessment

The analytical structure of environmental impact assessment is continually changing as the applicability of established techniques from other fields and the development of novel methods become known. This paper illustrates the applicability of using existing data bases, through a geographic information system, for theex ante evaluation of land use disruption. More specifically, the Canada Geographic Information System was employed to retrieve, to analyze, and to produce land capability statistics and land use maps for the proposed Glengowan dam and reservoir.