Costs and benefits of a cleaning mutualism

Juvenile Atlantic salmon or parr ( Salmo salar L.) maintain station at certain locations in flowing stream water. This position choice is assumed to involve the maximization of energy intake, based upon food availability which is usually directly related to water flow rate. Conversely energy expenditure, including station holding behaviour, foraging and defending preferred sites, is inversely related to water flow rate. Adaptations of parr to life in fast flows implies that station holding is energetically inexpensive at water speeds up to the maximum sustained holding speed, which is fish specific, thus the most important energetic consideration for parr is the ability to maximize food intake. Ten groups of three parr were each observed for 60 min within an artificial stream tank over a heterogeneous substratum. Individual position choice and behaviour were recorded continuously. For each location chosen by the parr the potential upstream line‐of‐sight (LOS), defined as the maximum distance upstream that the water surface would be visible, was calculated. At those sites where foraging behaviour was observed, the mean upstream potential LOS was significantly greater than at sites where other behaviours were observed and at 400 randomly generated sites within the tank. When foraging, parr usually take food from the stream drift and there is a significant time expenditure on food location, identification and catching. Results presented here would seem to confirm that to maximize time available to make these decisions, a fish would be expected to maximize the distance over which it can observe potential food particles.     

Health effects of supplemental work from home in the European Union

Internationalization and technological developments have changed the work organization in developed and developing industrial economies. Information and communication technologies, such as computers and smartphones, are increasingly used, allowing more temporal and spatial flexibility of work. This may lead to an increase in supplemental work, i.e. constant availability or working in addition to contractually agreed work hours. This in turn extends work hours and leads to work hours in evenings and weekends, causing interferences of work hours with biological and social rhythms for sleep, recovery and social interaction. However, empirical findings on the effects of supplemental work and work hours on occupational health are rather scarce. Therefore, the aim of this study was to investigate the association between (1) work-related contacts outside of regular work hours and (2) working in the free time with self-reported work-related health impairments in the fourth and fifth European Working Conditions Surveys (EWCS 2005, EWCS 2010). Out of these cross-sectional, large-scale surveys, data on n?=?22?836 and n?=?34?399 employed workers were used for weighted logistic regression analyses. About half of the sample reported at least occasional supplemental work. The results showed an increased risk of reporting at least one health problem for employees who had been contacted by their employer (EWCS 2005), or worked in their free time to meet work demands (EWCS 2010) in the last 12 months, compared to those reporting no supplemental work or work-related contacts during free time. These results were controlled for demographic variables, physical and mental work load, worker autonomy, and several work hours characteristics (e.g. hours per week, unusual and variable hours). The risk of reporting health problems was increased by being contacted both sometimes (Odds Ratio [OR] 1.26, 95% Confidence Interval [CI] 1.14–1.39) and often (OR 1.13, 95% CI 1.02–1.25), whereas the frequency of working in the free time showed a clear dose-response effect (sometimes: OR 1.14, 95% CI 1.04–1.24; often: OR 1.60, 95% CI 1.47–1.75), both compared to the category “never”. The findings, thus, indicate that even a small amount of supplemental work beyond contractually agreed work hours may increase the risk of work-related health impairments. Working in the free time was associated with a substantial risk increase and might be a better indicator for actual work load than being contacted by the employer outside of contractually agreed work hours. Thus, in order to minimize negative health effects, availability requirements for employees outside their regular work hours should be minimized. While these effects definitely need further study, especially regarding a quantification of actual supplemental work and its temporal location, addressing the company culture and using incentives and policies might be options to reduce the amount of supplemental work and maintain the risks of health impairments in the working population at a lower level.     

Regulatory pathways in the European Union

In principle, there are three defined procedures to obtain approval for a medicinal product in the European Union. As discussed in this overview of the procedures, the decision on which regulatory pathway to use will depend on the nature of the active substance, the target indication(s), the history of product and/or the marketing strategy.     

Work in the European Union.

Continental Europe is now only 20 minutes away by train from mainland Britain, and moving ever closer politically. Mutual recognition of medical qualifications within the European Union is well established: working in other parts of Europe is, in principle, straightforward. Working in different health care systems can offer new perspectives on British medical practice and the NHS. But the cultural differences are not always easy to overcome.     

Costs and benefits of female-biased natal philopatry in the common goldeneye

Sex-biased natal dispersal in long-lived species may resultin interactions between parents and mature young of the philopatricsex. To investigate the evolutionary basis of natal philopatryin a noncooperative species, the common goldeneye Bucephalaclangula, we studied possible costs and benefits of simultaneousbreeding of females and philopatric daughters. We did not find any fitness consequences of a daughter's breeding on their mother'sbreeding in terms of nest-site selection, body weight, clutchsize, hatching date, or hatching success. Our results, therefore,did not support the assumption of the local resource competitionhypothesis, that the natally philopatric sex should be morecostly to a breeding parent. As possible benefits for daughters returning to their natal area, we tested inheritance of nestsites from mothers and explored whether daughters utilize thepresence of their mother by parasitically sneaking into hermother's nest. Daughters' nest-site selection was not associatedwith the presence of their mothers. A comparison between daughtersand control females revealed that daughters chose their nestsite closer to their natal nest than expected by nest-siteavailability alone. Daughters could not expect to inherit anest site from their mother, and we did not find other indicationsof cooperation between relatives either. The mother's clutchsize did not increase in the year breeding with the daughter, indicating daughters do not parasitize their mother's nest.We suggest that benefits such as decreased nest predation riskassociated with nesting close to the natal nest site may beimportant in the natal philopatric behavior of the species.     

Costs and benefits of genetic heterogeneity within organisms

An increasing number of studies have recently detected within-organism genetic heterogeneity suggesting that genetically homogeneous organisms may be rare. In this review, we examine the potential costs and benefits of such intraorganismal genetic heterogeneity (IGH) on the fitness of the individual. The costs of IGH include cancerous growth, parasitism, competitive interactions and developmental instability, all of which threaten the integrity of the individual while the potential benefits are increased genetic variability, size-specific processes, and synergistic interactions between genetic variants. The particular cost or benefit of IGH in a specific case depends on the organism type and the origin of the IGH. While mosaicism easily arise by genetic changes in an individual, and will be the more common type of IGH, chimerism originates by the fusion of genetically distinct entities, and is expected to be substantially rare in most organisms. Potential conflicts and synergistic effects between different genetic lineages within an individual provide an interesting example for theoretical and empirical studies of multilevel selection.     

Costs and benefits of resistance against antimalarial drugs

Recent experiments have suggested that resistance to antimalarial drugs, in particular chloroquine, is associated with increased transmission. However, epidemiological patterns suggest the opposite: ie. that resistance should be associated with a transmission cost. Here, Jacob Koella reviews the evidence for either a cost or a benefit of chloroquine resistance and proposes ideas from population and evolutionary biology that might explain the apparent contradiction between experimental and epidemiological evidence.     

Attitudes toward biotechnology in the European Union

Public attitudes toward biotechnology in the European Union have been characterized as negative using Eurobarometer data, but so far little attention has been paid to building a robust metric appropriate for emerging public opinion issues which combine high salience with very limited knowledge by the public. On the basis of the general literature about the formation and structure of attitudes and about public perceptions of science, this article presents a new metric and analysis: first, for estimating the level of awareness and knowledge of biotechnology in Europe; second, for assessing the stability and depth of these evaluative perceptions; and third, for exploring the roles of canonical socio-demographic variables, the knowledge variable and general attitudinal schemas for understanding the perceptions of both benefits and risks of biotech applications. The results show the importance of general value orientations or "worldviews" in shaping positive attitudes, and more of these general cognitive schemas should be measured in future research. The same multivariate model was unable to account for a significant percentage of the total variance in the perception of risks, suggesting that new measures are needed to tap this critical area in the acceptance of biotech in Europe.     

Costs and benefits of jasmonic acid induced responses in soybean

In response to herbivory, plants have evolved defense strategies to reduce herbivore preference and performance. A strategy whereby defenses are induced only upon herbivory can mitigate costs of defense when herbivores are scarce. Although costs and benefits of induced responses are generally assumed, empirical evidence for many species is lacking. Soybean (Glycine max L. Merr.) has emerged as a model species with which to address questions about induced responses. To our knowledge, this is the first study to examine the fitness costs and benefits of jasmonic acid-induced responses by soybean in the absence and presence of soybean loopers (Chrysodeix includens Walker) (Lepidoptera: Noctuidae). In a greenhouse experiment we demonstrated that soybean induction was costly. Induced plants produced 10.1% fewer seeds that were 9.0% lighter, and had 19.2% lower germination rates than noninduced plants. However, induction provided only modest benefits to soybeans. In a choice experiment, soybean loopers significantly preferred leaves from noninduced plants, consuming 62% more tissue than from induced plants. Soybean loopers that fed on plants that were previously subjected to treatment with jasmonic acid matured at the same rate and to the same size as those that fed on control plants. However, at high conspecific density, soybean looper survivorship was reduced by 44% on previously induced relative to control plants. Reduced soybean looper preference and survivorship did not translate into fitness benefits for soybeans. Our findings support theoretical predictions of costly induced defenses and highlight the importance of considering the environmental context in studies of plant defense.     

Weed biological control in the European Union: from serendipity to strategy

Biological control of weeds is a globally recognised approach to the management of some of the most troublesome invasive plants in the world. Accidental introductions of agents accounted for all weed biological control agent establishments in the European Union until 2010, but these examples include some current or emerging control successes both large and small, from the redistribution of the weevil Stenopelmus rufinasus Gyllenhal (Coleoptera: Curculionidae) for the control of small outbreaks of Azolla filiculoides Lam. (Azollaceae), to the large scale control provided by the cochineal insect Dactylopius opuntiae (Cockerell) (Hemiptera: Dactylopiidae), used against some problematic prickly pears (Opuntia spp. (Cactaceae)), and the ragweed beetle Ophraella communa LeSage (Coleoptera: Chrysomelidae), against common ragweed, Ambrosia artemisiifolia L. (Asteraceae), which are providing benefits to an increasing number of Member States of the European Union. Recent programmes involving the intentional introduction of biological control agents against target weeds including Fallopia japonica (Hout.) Ronse Decr. (Polygonaceae), Impatiens glandulifera Royle (Balsaminaceae) and Acacia longifolia (Andrews) Willd (Fabaceae) show a shift from luck to judgement in the European Union. The inclusion of new weed targets on the European Invasive Species Regulation should lead to a growth in the profile and use of biological control which would be assisted by the publication of any successes from the few intentional introductions covered in this paper.     

Strategic dilemmas of biosecurity in the European Union

Systems for societal/homeland security in both Europe and the United States are in flux to adjust to 21st century threats, such as terrorism, the proliferation of weapons of mass destruction, regional conflicts, state failures, and organized crime. It is important that reforms take place on both sides of the Atlantic that recognize the interdependence of Europe and the United States. Security, including biosecurity, for Europe is strongly connected to security in the U.S. Diseases transcend borders, and their consequences can be the same, irrespective of where the outbreak occurs or whether it is a natural occurrence or an act of bioterrorism. This article examines the political and strategic dilemmas and complexities that would confront the European Union (EU) in the event of a bioterrorism attack or a naturally occurring outbreak. Although several initiatives have been taken by the 15 member states and within the EU Commission, the EU is not institutionally prepared for transnational, rapidly moving diseases that could cause grave consequences in Europe and other regions, including the U.S. The prime responsibility for protecting European citizens against outbreaks rests with each member state. However, with intertwined and open European societies, the consequences would likely spill across borders. The EU Commission would have to become involved because such aspects as the internal market and freedom of movement would be affected. Responsibility, but not authority, would be pushed to the top. A coordinated EU response to such crises depends on European political leadership.     

Costs and benefits of a superinfection of facultative symbionts in aphids

Symbiotic associations between animals and inherited micro-organisms are widespread in nature. In many cases, hosts may be superinfected with multiple inherited symbionts. Acyrthosiphon pisum (the pea aphid) may harbour more than one facultative symbiont (called secondary symbionts) in addition to the obligate primary symbiont, Buchnera aphidicola. Previously we demonstrated that, in a controlled genetic background, A. pisum infected with either Serratia symbiotica or Hamiltonella defensa (called R- and T-type in that study) were more resistant to attack by the parasitoid Aphidius ervi. Here, we examined the consequences of A. pisum superinfected with both resistance-conferring symbionts. We found that an A. pisum line co-infected with both S. symbiotica and H. defensa symbionts exhibits even greater resistance to parasitism by A. ervi than either of the singly infected lines. Despite this added benefit to resistance, superinfections of S. symbiotica and H. defensa symbionts appeared rare in our survey of Utah A. pisum symbionts, which is probably attributable to severe fecundity costs. Quantitative polymerase chain reaction estimates indicate that while the density of H. defensa is similar in singly and superinfected hosts, S. symbiotica densities increased dramatically in superinfected hosts. Over-proliferation of symbionts or antagonistic interactions between symbionts may be harmful to the aphid host. Our results indicate that in addition to host-symbiont interactions, interactions among the symbionts themselves probably play a critical role in determining the distributions of symbionts in natural populations.