Selective olfactory attention of a specialised predator to intraspecific chemical signals of its prey

Prey-specialised predators have evolved specific cognitive adaptations that increase their prey searching efficiency. In particular, when the prey is social, selection probably favours the use of prey intraspecific chemical signals by predatory arthropods. Using a specialised ant-eating zodariid spider, Zodarion rubidum, which is known to prey on several ant species and possesses capture and venom adaptations more effective on Formicinae ants, we tested its ability to recognise chemical cues produced by several ant species. Using an olfactometer, we tested the response of Z. rubidum towards air with chemical cues from six different ant species: Camponotus ligniperda, Lasius platythorax and Formica rufibarbis (all Formicinae); and Messor structor, Myrmica scabrinodis and Tetramorium caespitum (all Myrmicinae). Z. rubidum was attracted to air carrying chemical cues only from F. rufibarbis and L. platythorax. Then, we identified that the spiders were attracted to airborne cues coming from the F. rufibarbis gaster and Dufour's gland, in particular. Finally, we found that among several synthetic blends, the decyl acetate and undecane mixture produced significant attraction of spiders. These chemicals are produced only by three Formicine genera. Furthermore, we investigated the role of these chemical cues in the communication of F. rufibarbis and found that this blend reduces their movement. This study demonstrates the chemical cognitive capacity of Z. rubidum to locate its ant prey using chemical signals produced by the ants. The innate capacity of Z. rubidum to olfactory detect different ant species is narrow, as it includes only two ant genera, confirming trophic specialisation at lower than subfamily level. The olfactory cue detected by Zodarion spiders is probably a component of the recruitment or trail pheromone.     

Modelling the Competitive Sorption Process of Multiple Solutes During their Transport in Porous Media

A general mathematical model to solve the advection–dispersion transport equation for multiple solutes was developed, where the dual porosity mobile–immobile mass transfer, the two-site non-equilibrium model and first-order transformation reactions were included. The two-site model was expressed with an equilibrium sorption term and a kinetic term. One of three kinetic models could be used: the non-linear, the bilinear and the pore diffusion model. The traditional Freundlich or Langmuir isotherms were employed to simulate no-interaction between the solutes, but with the extended Freundlich or extended Langmuir isotherms, a competitive sorption could be simulated. The transport equation was solved with the Moving Concentration Slope method. The mathematical model was tested and further simplified by using real data from soil column experiments, with 1,2-cis-dichloroethene and trichloroethene as model contaminants and silica gel and real soil samples as porous medium.     

Pathogen-induced hatching and population-specific life-history response to waterborne cues in brown trout (Salmo trutta)

Hatching is an important niche shift, and embryos in a wide range of taxa can either accelerate or delay this life-history switch in order to avoid stage-specific risks. Such behavior can occur in response to stress itself and to chemical cues that allow anticipation of stress. We studied the genetic organization of this phenotypic plasticity and tested whether there are differences among populations and across environments in order to learn more about the evolutionary potential of stress-induced hatching. As a study species, we chose the brown trout (Salmo trutta; Salmonidae). Gametes were collected from five natural populations (within one river network) and used for full-factorial in vitro fertilizations. The resulting embryos were either directly infected with Pseudomonas fluorescens or were exposed to waterborne cues from P. fluorescens-infected conspecifics. We found that direct inoculation with P. fluorescens increased embryonic mortality and induced hatching in all host populations. Exposure to waterborne cues revealed population-specific responses. We found significant additive genetic variation for hatching time, and genetic variation in trait plasticity. In conclusion, hatching is induced in response to infection and can be affected by waterborne cues of infection, but populations and families differ in their reaction to the latter.     

Gametogenesis,embryogenesis, and larval features of the oviparous sponge <Emphasis Type="Italic">Petrosia ficiformis</Emphasis> (Haplosclerida,Demospongiae)

This study describes the reproductive cycle of Petrosia ficiformis and documents for the first time embryogenesis in an oviparous haplosclerid demosponge. Gonochoric adults, occurring in 2:1 female/male ratios, spawned in late autumn, after a 7-month long oogenesis and a 2.5-week-long spermatogenesis. Following a remarkable migration, the oocytes were released as 250 μm eggs bearing attached polar bodies and a thin mucous cover. Round-headed spermatozoa with three large mitochondria, and many proacrosomal vesicles fertilized the eggs externally. A fertilization membrane appeared around the zygotes. Nearly equal and total cleavage led to a stereoblastula that subsequently became an entirely ciliated larva. The larva alternated spherical and multilobate body shape and consisted of undifferentiated cells. It had poor abilities to swim and glide, probably experiencing passive dispersal and unselective attachment. Settlers developed choanocyte chambers after 1.5 months. Symbiotic microbes were absent from gametes and larvae, being necessarily acquired from the ambient at each sponge generation. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

从《老子想尔注》看早期道教构建理想社会的初步尝试

《老子想尔注》认为实现理想社会的前提条件是"尊道"。道不仅是一个哲学概念,在这里被发挥成至高无上的太上老君,成为理想社会的掌控者。《老子想尔注》理想社会的理论在批判现实问题的基础上展开论述,主要讨论了君臣关系、伦理道德和贫富差异等。维系理想社会秩序的手段是道诫,道诫超越法律,内涵丰富。     

U-series disequilibria in a groundwater flow route as an indicator of uranium migration processes

U-series data relating to groundwater, fracture coatings and the adjoining rock matrix in a groundwater flow system at the Palmottu natural analogue site was examined. The aim was to obtain an experimental reference for migration modelling in a transport section defined within the flow system. The U-series reference obtained turned out to be a very useful tool for fine tuning the flow route and for migration mechanism considerations. The U-series data are well in line with other interpretations of the migration system.     

Balkanized Research in Ecological Engineering Revealed by a Bibliometric Analysis of Earthworms and Ecosystem Services

Energy crisis, climate changes, and biodiversity losses have reinforced the drive for more ecologically-based approaches for environmental management. Such approaches are characterized by the use of organisms rather than energy-consuming technologies. Although earthworms are believed to be potentially useful organisms for managing ecosystem services, there is actually no quantification of such a trend in literature. This bibliometric analysis aimed to measure the evolution of the association of “earthworms” and other terms such as ecosystem services (primary production, nutrient cycling, carbon sequestration, soil structure, and pollution remediation), “ecological engineering” or “biodiversity,” to assess their convergence or divergence through time. In this aim, we calculated the similarity index, an indicator of the paradigmatic proximity defined in applied epistemology, for each year between 1900 and 2009. We documented the scientific fields and the geographical origins of the studies, as well as the land uses, and compare these characteristics with a 25 years old review on earthworm management. The association of earthworm related keywords with ecosystem services related keywords was increasing with time, reflecting the growing interest in earthworm use in biodiversity and ecosystem services management. Conversely, no significant increase in the association between earthworms and disciplines such as ecological engineering or restoration ecology was observed. This demonstrated that general ecologically-based approaches have yet to emerge and that there is little exchange of knowledge, methods or concepts among balkanized application realms. Nevertheless, there is a strong need for crossing the frontiers between fields of application and for developing an umbrella discipline to provide a framework for the use of organisms to manage ecosystem services.     

Electrostatic precipitation of ultrafine particles enhanced by simultaneous diffusional deposition on wire screens

A laboratory-scale electrostatic precipitator has been designed and constructed in which the grounded collector plate has been substituted by a set of wire screens placed perpendicularly to the gas flow. Particles are deposited onto the screens by two mechanisms--electrostatic deposition and diffusional deposition--which act simultaneously. On the one hand, electrostatic deposition is effective for relatively large particles, but it is quite ineffective for the smallest ones because their charging probability in the corona field is too low. On the other hand, the diffusional collection efficiency of particles on fibers is high for small particles but low for the larger ones. Therefore, the simultaneous diffusional-electrostatic precipitation may become a useful technique for efficient filtration of particles below 0.1 microm. A preliminary experimental evaluation of this filtering device has shown that submicrometer particles with diameters down to a few nanometers can be collected with number efficiencies greater than 99%.