Avian cestodes affect the behaviour of their intermediate host Artemia parthenogenetica: an experimental study

The brine shrimp Artemia parthenogenetica (Crustacea, Branchiopoda) is intermediate host for several cestode species whose final hosts are waterbirds. Previous field studies have shown that brine shrimps infected with cestodes have a bright red colour and are spatially segregated in the water column. However, the ethological mechanisms explaining such field observations are unknown. Changes in appearance and behaviour induced by trophically transmitted parasites have been shown to increase the risk of predation by the final host. In this experimental study, we compared the behaviour of uninfected Artemia and those infected by avian cestodes. We found that parasitised individuals behave differently from unparasitised ones in several ways. In contrast to uninfected individuals, infected brine shrimps were photophilous and showed increased surface-swimming behaviour. These observations suggest that the modified behaviour (in addition to the bright red colour of the majority of the infected individuals) results in infected brine shrimps becoming more vulnerable to avian final hosts, which facilitates parasite transmission. We discuss our results in terms of the adaptive nature of behavioural changes and their potential implications for the hypersaline ecosystem.     

Comparing the potential for dispersal via waterbirds of a native and an invasive brine shrimp

1. Migratory waterbirds are likely to have a major role in the spread of many exotic aquatic invertebrates by passive dispersal. However, in the field, this has so far only been confirmed in the case of the American brine shrimp Artemia franciscana, which is spreading quickly around the Mediterranean region. 2. We compared experimentally the capacity of A. franciscana and the native brine shrimp Artemia parthenogenetica to disperse via migratory shorebirds. After Artemia resting eggs (cysts) were fed to Redshank Tringa totanus and Dunlin Calidris alpina, we compared the proportion that survived gut passage, their hatchability and their retention time within the gut. We also tested the ability of cysts to stick to the feathers of Black‐tailed Godwit Limosa limosa. 3. The proportion of ingested cysts retrieved from faeces was the same for each Artemia species (8%), and there were no significant differences in retention time (mean 1.2 h and maximum 10 h for A. parthenogenetica, 1.4 and 12 h for A. franciscana) or hatchability (11% versus 14%). The two shorebird species showed similar retention times and retrieval rates, but cysts recovered from Dunlin had a significantly higher hatchability. Only one of the 1000 A. parthenogenetica cysts and three of the 1000 A. franciscana cysts stuck to feathers. 4. These results indicate that both non‐native and native brine shrimps have a similar high capacity for endozoochory via birds, and that the invasiveness of A. franciscana is probably explained by its competitive superiority owing to high fecundity and release from cestode parasitism. Owing to their different migratory behaviour, Redshank and Dunlin are likely to have different roles as brine shrimp vectors. Brine shrimps provide a suitable model for understanding the role of birds in the dispersal of exotic aquatic invertebrates.     

Cell surface NADH oxidase activity of brine shrimp oscillates with a period of 25 min and is entrained by light

Plants have a surface NADH oxidase that measures time by oscillating with a 24-min period. The period is synchronized by light. With plants, a new maximum is observed exactly 12 min after the beginning of the light exposure. These experiments were to determine if animals exhibited a cell surface NADH oxidase having a similar periodicity and to answer the question, does the periodicity in animals respond to light? Using brine shrimp as a model, the findings show that plants and animals exhibit similar oscillating NADH oxidase activity and that the periodicity in this invertebrate animal does respond to light. Brine shrimp were grown for two to three days and transferred to darkness for 45 min. After return to light for one min, NADH was added and measurements of NADH oxidation were recorded over 50 min. The brine shrimp exhibited a cell surface NADH oxidase that oscillated with a period of 25 min. After being subjected to light, the brine shrimp showed a new maximum in NADH oxidation between 12 to 13 min after the beginning of the light exposure and again at 37 min and at 25 min intervals thereafter. The findings demonstrate that the periodic oscillations in NADH oxidation of brine shrimp are light entrainable.     

Considerations on the possibility of microbial clogging of re-injection wells of the wastewater generated in a water-dissolved natural gas field

Brine produced from water-dissolved natural gas reservoirs should be returned to the reservoirs after the resources are recovered to prevent land subsidence. However, the ability to re-inject the brine gradually decreases and is only rectified by carrying out backwashing treatment of re-injection wells. Because the brine contains high levels of iodine also, it is also recovered from the brine using sulfuric acid and oxidizing agents. These chemicals may stimulate the growth of microorganisms that may cause the clogging. In this study, we used column experiments to investigate the possibility of the microbial clogging.Significant clogging was observed on the columns that were treated by the brine containing both indigenous microorganisms and dissolved oxygen. In particular, iodide-oxidizing bacteria were detected from the columns and original brine dominantly; therefore, it was assumed to have an important influence on the clogging. Iodine that was produced by iodide-oxidizing bacteria corroded iron in the sand under the presence of dissolved oxygen. Eluted Iron formed ferric hydroxide colloid in the brine and it caused the clogging of the pore spaces.We also demonstrated that deoxidized brine inhibited the iodide-oxidizing bacteria from becoming dominant and the column from the clogging through the column experiments. From these results, we can suggest removing dissolved oxygen as the most feasible countermeasures for the clogging.     

Social learning in animals: comparative analysis of different forms and levels

Social learning as one of the key concepts of cognitive ecology includes different forms of behavioural displays from relatively simple, such as "social release" and "stimulus enhancement" up to "teaching" and "cultural transmission" in animal communities. Rapid development of this fields resulted in some contradictions in methods and terminology. In this review different forms and levels of social learning are analyzed. Ecological aspects of social learning are connected with diet shaping, fear of predators and mate choice. The first aspect is the most studied but still discussible. Social learning being an intricate component of feeding behaviour matches with innate behaviour, imprinting as well as early associative learning. Investigation of cognitive aspects of social learning going back to Thorndike's crucial question "Do apes ape?" are now developing into series of questions including even: "Do ants ape?". Elaboration of universal methods of comparative studying of social learning such as "artificial fruit" and "two ways/one outcome" has essentially enlightened these questions and made comparative analysis possible. Large continuum of displays of cognitive skills in social learning has been revealed in non-primate species. One of the discussible issues in the role of social learning is distribution of innovations. Many authors have investigated this intriguing aspect of animal behaviour in different ways, such as long field observations as well as laboratory experiments based on "artificial innovators" that is specimens specially taught by experimentalists. Many impressive results were obtained; in particular it turned out in contradiction with some mathematical models that individuals in groups are rather different in their psychophysiological predisposition to innovative behaviour. Role of teaching in such different forms of behaviour as shaping of species-specific behavioural patterns and spread of innovations is considered. Although the majority of animals in wild populations are not good teachers and pupils, some cultural aspects of behaviour were recently revealed, mostly in primates. At the same time some classical results concerning cultural transmission of new patterns (for example, bottle-opening in tits) were experimentally revised. Many problems still remain unsolved, in particular, how spread of innovations may favour prosperity of populations; to what degree behavioural peculiarities of local groups may be determined by processes of social learning; which internal and external factors and under what circumstances invest into social learning in natural environment.     

Brine shrimps adrift: historical species turnover in Western Mediterranean Artemia (Anostraca)

Biological Invasions - Brine shrimps (Artemia) have undergone geographic range and demographic expansions as a result of their interaction with humans since the beginning of salt harvesting. This...     

The Concept of Animal Welfare at the Interface between Producers and Scientists: The Example of Organic Pig Farming

In organic farming animal welfare is one important aspect included in the internationally agreed organic principles of health, ecology, fairness and care (IFOAM 2006), reflecting expectation of consumers and farmers. The definition of organic animal welfare includes—besides traditional terms of animal welfare—‘regeneration’ and ‘naturalness’. Organic animal welfare assessment needs to reflect this and use complex parameters, include natural behaviour and a systemic view. Furthermore, various parties with seemingly conflicting interests are involved, causing ethical dilemmas, such as the use of nose rings for outdoor sows (impaired animal welfare vs. destruction of humus). Solutions can only be found when foundational concepts are translated and applied to practical situations. On-farm animal welfare assessment and implementation of improvement strategies are increasingly relevant scientific areas. They combine on-farm welfare assessment, identification of key problem areas and connected risk factors. Constant communication between all parties is crucial for success. Animal health and welfare planning is one application of this approach, which was carried out on Austrian organic pig farms as well as organic dairy farms in seven European countries. The projects included welfare assessment, feedback and benchmarking as a tool for communication between farmers, advisors and scientists. Finally goals were set by the farmer and improvement strategies applicable to organic farming were implemented. This included prevention of disease by management strategies instead of routine treatment with pharmaceutical products. It appeared that next to problem structuring, multidisciplinary problem solving demands good communications skills to relate animal welfare science to value reflections.     

The key role of behaviour in animal camouflage

Animal camouflage represents one of the most important ways of preventing (or facilitating) predation. It attracted the attention of the earliest evolutionary biologists, and today remains a focus of investigation in areas ranging from evolutionary ecology, animal decision‐making, optimal strategies, visual psychology, computer science, to materials science. Most work focuses on the role of animal morphology per se, and its interactions with the background in affecting detection and recognition. However, the behaviour of organisms is likely to be crucial in affecting camouflage too, through background choice, body orientation and positioning; and strategies of camouflage that require movement. A wealth of potential mechanisms may affect such behaviours, from imprinting and self‐assessment to genetics, and operate at several levels (species, morph, and individual). Over many years there have been numerous studies investigating the role of behaviour in camouflage, but to date, no effort to synthesise these studies and ideas into a coherent framework. Here, we review key work on behaviour and camouflage, highlight the mechanisms involved and implications of behaviour, discuss the importance of this in a changing world, and offer suggestions for addressing the many important gaps in our understanding of this subject.     

Fluxes associated with brine motion in growing sea ice

Summary Laboratory and field studies have demonstrated that fluid motion occurs at two locations in growing sea ice: in a network of brine channels and within the skeletal layer at the ice-water interface. Brine channel fluxes estimated using brine channel areal density from natural sea ice and channel velocities from laboratory studies are compared with recent measurements reported in the literature. Fluxes into the porous skeletal layer of sea ice may be estimated using rates of nutrient uptake by ice algae and adjacent seawater nutrient concentrations. Both approaches indicate fluxes of the order of 10^-6 cc cm^-2 s^-1 (l m^-2 h^-1), which are about equal to fluxes reported in bioirrigated sediments. Fluxes of this magnitude indicate a very short residence time for the liquid phase in the skeletal layer, suggesting that this fluid motion may be important in maintaining the ice algae community.     

Science out of the classroom

A recent survey estimates that 65% of secondary-age school children (11–16 years) in the UK have access tothe Internet at home.Most pupils are, therefore, already learning through information and communicationtechnology (ICT). Butthere are still questions about how ICT is being used for teaching science in schoolswithin the UK.     

The ethics of intervening in animal behaviour for conservation

Conservation behaviour is a growing field that applies insights from the study of animal behaviour to address challenges in wildlife conservation and management. Conservation behaviour interventions often aim to manage specific behaviours of a species to solve conservation challenges. The field is often viewed as offering approaches that are less intrusive or harmful to animals than, for example, managing the impact of a problematic species by reducing its population size (frequently through lethal control). However, intervening in animal behaviour, even for conservation purposes, may still raise important ethical considerations. We discuss these issues and develop a framework and a decision support tool, to aid managers and researchers in evaluating the ethical considerations of conservation behaviour interventions against other options.     

Sandpipers Select Red Brine Shrimps Rich in Both Carotenoids and Parasites

Cestode parasites using brine shrimps Artemia as intermediate hosts and waterbirds as final hosts are known to change the colour of shrimps from pale pink to bright red owing to an increase in carotenoid pigments. In order to assess whether this coloration increases the chances of shrimp predation by the final host, we conducted an experiment in which 10 Calidris sandpipers were given a choice of 20 bright red and 20 pale pink shrimps. A strong preference for red, infected shrimps was recorded, suggesting that red colour is a manipulation by cestodes to increase transmission to its final hosts. The factors regulating access and functions of carotenoids in birds are under intense debate. For the first time, we show that access to carotenoid-rich foods in birds can have a cost derived from an increased exposure to parasites. To our knowledge, this is the first time that avian hosts have been shown to exert a colour-based preference for parasitized prey.     

Host behaviour–parasite feedback: an essential link between animal behaviour and disease ecology

Animal behaviour and the ecology and evolution of parasites are inextricably linked. For this reason, animal behaviourists and disease ecologists have been interested in the intersection of their respective fields for decades. Despite this interest, most research at the behaviour–disease interface focuses either on how host behaviour affects parasites or how parasites affect behaviour, with little overlap between the two. Yet, the majority of interactions between hosts and parasites are probably reciprocal, such that host behaviour feeds back on parasites and vice versa. Explicitly considering these feedbacks is essential for understanding the complex connections between animal behaviour and parasite ecology and evolution. To illustrate this point, we discuss how host behaviour–parasite feedbacks might operate and explore the consequences of feedback for studies of animal behaviour and parasites. For example, ignoring the feedback of host social structure on parasite dynamics can limit the accuracy of predictions about parasite spread. Likewise, considering feedback in studies of parasites and animal personalities may provide unique insight about the maintenance of variation in personality types. Finally, applying the feedback concept to links between host behaviour and beneficial, rather than pathogenic, microbes may shed new light on transitions between mutualism and parasitism. More generally, accounting for host behaviour–parasite feedbacks can help identify critical gaps in our understanding of how key host behaviours and parasite traits evolve and are maintained.     

Ecology: The Science Versus the Myth

This paper describes the foundations of ecology as a science and argues for adherence to scientific principles in the environmental arena. Ecology as a science does not present moral or ethical guidance for societal use in environmental management. Moral, ethical, economic, and political values are integral parts of environmental management, but they are derived outside the realm of science. We emphasize the importance of preserving the power of science as a methodology to acquire objective information separated from societal values. Environmental Risk Assessment is a process that engages and requires both the life and social sciences for successful environmental management.     

The experiments with laboratory animals from a bioethical point of view--history, modern time, perspectives

The origin of laboratory animal science was called forth by violent development of experimental biology and medicine in the XIX century on the one hand, and on the other hand by the necessity to have standard healthy animals for experiments with strictly definite biological characteristics. With this aim in view management technology and animal use in experiments have been constantly improved. "Laboratory animal" notion has been formed by the end of the XIX century. At the beginning of laboratory animal science development ethical problems were not as urgent as they are now. It is established that the three Rs bioethical conception of W.M.S. Russel and R.L. Burch (1959) has influence on modern state and perspectives of the development of animal experimental methods. It is shown that the existence of laboratory animal protection laws and the reflection in them of compulsory ethical review of scientific project and statistics of used laboratory animals is absolutely necessary.     

Competing Conceptions of Animal Welfare and Their Ethical Implications for the Treatment of Non-Human Animals

Animal welfare has been conceptualized in such a way that the use of animals in science and for food seems justified. I argue that those who have done this have appropriated the concept of animal welfare, claiming to give a scientific account that is more objective than the “sentimental” account given by animal liberationists. This strategy seems to play a major role in supporting merely limited reform in the use of animals and seems to support the assumption that there are conditions under which animals may be raised and slaughtered for food that are ethically acceptable. Reformists do not need to make this assumption, but they tend to conceptualize animal welfare is such a way that death does not count as harmful to the interests of animals, nor prolonged life a benefit. In addition to this prudential value assumption, some members of this community have developed strategies for defending suitably reformed farming practices as ethical even granting that death and some other forms of constraints are harms. One such strategy is the fiction of a domestic contract. However, if one accepts the conceptualization of human welfare give by L. W. Sumner, and applies it to animals in the way that I think is justified, an accurate conceptualization of animal welfare has different implications for which uses of animals should be regarded as ethically acceptable. In this paper I give an historical and philosophical account of animal welfare conceptulization and use this account to argue that animal breeders, as custodians of the animals they breed, have the ethical responsibility to help their animal wards achieve as much autonomy as possible in choosing the form of life made available to them and to provide that life. Attempts to avoid these implications by alluding to a contract model of the relationship between custodians and their wards fail to relieve custodians of their ethical responsibilities of care.     

Keeping Small Mammals in Schools A Note on Maintenance Costs

The brine shrimp, Artemia salina, is a small marine invertebrate. Although not generally used in schools, it has many advantages as an animal for experimental investigation. It is widely available, cheap, and easily cultured. A large number of experiments can be devised to investigate such factors as the importance of salinity on egg hatching success rale, and the effects of temperature and density-dependent competition for food on growth rates. Observations can also be made on development and reproductive behaviour. This paper includes a general account of the biology of Artemia, instructions on how the organism may be cultured, the results of some experiments on the ecology and population biology of the species, and some suggestions for further studies.     

The brine shrimp's tale: a topsy turvy evolutionary fable

It has been suggested that: (1) the brine shrimp, Artemia (Branchiopoda: Anostraca), which habitually swims inverted, has 'only recently turned over'; (2) if this habit were to persist for tens of millions of years, original dorsal–ventral homologies would become obliterated; (3) it would become necessary to re-define the concept of dorsal and ventral because so many details would have changed over evolutionary time; and (4) if modern brine shrimps were to maintain the habit of swimming upside down for 100 Myr into the future, they might give rise to a whole new subkingdom whose descendants would be defined as having a dorsal nerve cord. However, brine shrimps and their allies have not recently turned over. All the nearly 300 extant anostracans swim inverted, and members of the order have clearly done so for more than 400 Myr, yet their anatomical arrangements are the same as in crustaceans that live dorsal side up. Nor do crustaceans that swim inverted and even hang from the surface film depart from the standard arrangement. The claim that inverted swimming became a genetically determined attribute of brine shrimps via the operation of the so-called Baldwin effect is rejected, as is the concept itself.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 88 , 377–382.     

The Influence of water salinity on the free amino acid concentration in muscle and hepatopancreas of adult shrimps, Penaeus japonicus

Variations of the total free amino acid (FAA) pool and the content of specific amino acids have been measured in the muscle and hepatopancreas of adult shrimps, Penaeus japonicus, acclimatized at five water salinities: 38, 32, 26, 20 and 14%‰ The FAA content is always higher in muscle than in hepatopancreas at all tested salinites. On the other hand, the hepatopancreas exhibits the highest concentrations of essential amino acids. Two steps in the evolution of FAA content can be observed, the first one regarding decrease in salinity from 38 to 20%‰ and the second one, when salinity goes below 20%_°. The first step can be characterized by a 16% decrease of total FAA content in the muscle and a 36% increase in the hepatopancreas. In muscle, the variations are mainly due to changes in non-essential FAA content, whereas in the hepatopancreas, they are linked to variations in essential FAA content. The other step is characterized by a drastic increase in moisture and decrease in FAA content in both studied organs when water salinity is 14%‰ The total FAA content is about 40% lower in shrimps at 14%_° compared to 38%‰ seawater salinity. During adaptation, the FAA pool (mainly NEFAAs) of muscle seems to be directly related to osmoregulation, whereas in the hepatopancreas, its evolution seems to be linked with energy expenditure and protein synthesis. The results are evaluated in order to elucidate the role of FAA in intracellular osmoregulation and in relation to animal ecology.     

The Teaching of Photosynthesis in Secondary School: A History of the Science Approach

In this article we present a synthesis of the research affecting pupils' conceptions of photosynthesis and plant nutrition. The main false conceptions of the pupils identi?ed in this literature review are: that green plants ?nd their food in the soil; that water and mineral salts are suf?cient to the growth of a plant; the role of chlorophyll, where the transformation of luminous energy into chemical energy is never evoked; and air as a source of matter, which is never underlined. Secondly, we are going to see that several of these false conceptions have been developed during history. For example, the famous philosopher Aristotle (384–322 BC) thought that plants receive their food from the soil already elaborated. Several centuries later, the physician and chemist Van Helmont (1677–1644) added more precision to Aristotle’s conception while claiming that plants use only water for their growth. Finally, we will see that the analysis of the false theories developed during history will permit in a context of teaching to valorize the false conceptions of the pupils. Indeed, the history of sciences could incite a teacher to valorize his pupils’ false conceptions while considering them as an indication of difficulties that deserve particular pedagogical and didactic tools. The false conceptions constructed by the pupils don’t have to be ignored in a teaching context because they obey particular reasoning rules, sometimes similar to those that once guided some scientific steps. This view, drawing on false conceptions developed during history, gives a dynamic and human picture of the science very distant from the one sometimes carried on by dogmatic teaching.