Identification of 1-methyloctyl butanoate as the major sex pheromone component from females of the saddle gall midge,Haplodiplosis marginata (Diptera: Cecidomyiidae)

The saddle gall midge, Haplodiplosis marginata (von Roser) (Diptera: Cecidomyiidae), has undergone a resurgence recently as a pest of cereals in Belgium and other European countries. An effective monitoring tool of saddle gall midge flights is needed to understand the enigmatic population dynamics of this pest, and to design an integrated management strategy. Therefore, volatile compounds emitted by females (alkan-2-ols and alk-2-yl butanoates) were identified, and the chirality of the emitted esters was determined to be the R absolute configuration. In field-trapping experiments, racemic non-2-yl butanoate attracted substantial numbers of H. marginata males. Thus, this compound will be useful in baited traps for monitoring seasonal flight patterns, and improving integrated management of the saddle gall midge in agricultural systems.     

In vivo exposure of Mytilus edulis to living enteric bacteria: a threat for immune competency?

Mussels are widespread in coastal environments and experience various physical, chemical, and bacteriological conditions. Owing to the increase of coastal urbanization, mussels are now commonly exposed not only to indigenous bacteria, but also to enteric bacteria originating from pulsed and chronic sewage discharges into coastal environments. Due to its broad resilience to environmental variations, the blue mussel Mytilus edulis is commonly used as an indicator of environmental quality in bio-monitoring programs. However, since mussel immune system capabilities may be affected by the presence of exogenous fecal bacteria in coastal seawater subjected to sewage discharges, we aimed to determine the effect of in vivo bacterial challenges on mussels' immune competency by using two exogenous enteric bacterial strains, Escherichia coli and Enterococcus faecalis, and an indigenous bacterial strain Vibrio splendidus (as control). Bacterial strains were tested individually, by injection into the posterior adductor muscle at three different cell densities (10², 10³, and 10⁴ cells). Unlike classic in vitro experiments using higher bacterial concentrations, neither the enteric bacteria nor the indigenous strain induced significant increase or decrease of either cell-mediated (phagocytosis, reactive oxygen species, and NO _x production) or humoral components (prophenoloxidase-like, acid phosphatase, and l-leucine-aminopeptidase production) of the immune system. This study demonstrates that, at low concentrations, E. coli and E. faecalis do not represent an additional threat that could impair M. edulis immune competency and, as a consequence, its potential of survival in coastal areas subjected to sewage discharges.     

Assessment of aided phytostabilization of copper-contaminated soil by X-ray absorption spectroscopy and chemical extractions

Field plots were established at a timber treatment site to evaluate remediation of Cu contaminated topsoils with aided phytostabilization. Soil containing 2600 mg kg⁻¹ Cu was amended with a combination of 5 wt% compost and 2 wt% iron grit, and vegetated. Sequential extraction was combined with extended X-ray absorption fine structure (EXAFS) spectroscopy to correlate changes in Cu distribution across five fractions with changes in the predominant Cu compounds two years after treatment in parallel treated and untreated field plots. Exchangeable Cu dominated untreated soil, most likely as Cu(II) species non-specifically bound to natural organic matter. The EXAFS spectroscopic results are consistent with the sequential extraction results, which show a major shift in Cu distribution as a result of soil treatment to the fraction bound to poorly crystalline Fe oxyhydroxides forming binuclear inner-sphere complexes.     

Atmospheric Polycyclic Aromatic Hydrocarbons at a Point Source of Emissions. Part A: Identification and Determination of Polycyclic Aromatic Compounds in Airborne Particulate Matter Near a Horizontal Stud Soderberg Plant

Abstract

This paper summarizes the sampling and analytical methods developed to identify and measure polycyclic aromatic hydrocarbons (PAH) and related aromatic compounds near a Horizontal Stud Soderberg plant at Jonquiere, Quebec, Canada. The primary source of PAH is the coal tar pitch used as a binder in Soderberg anodes. Twice a week at a number of sampling sites, airborne particulate matter was collected on glass-fiber filters using a Hi-Vol sampler for a twenty-four hour period. Organics on the filter were Soxhlet extracted with benzene.

Identification was done by gas chromatography-mass spectrometry (GC-MS). The vast majority of compounds present were PAH, but small amounts of alkyl PAH and polycyclic aromatic compounds with heteroatoms such as nitrogen, oxygen and sulfur were also identified. Based on the GC-MS identification, a group of 14 PAH was selected for monitoring. Frequent PAH determinations revealed that the ratio of Benzo(a- )Pyrene to total PAH on the Hi-Vol filters is relatively constant in ambient air from one sampling station to another.     

Resilience and Challenges of Marine Social–Ecological Systems Under Complex and Interconnected Drivers

In this paper, we summarize the contributions made by an interdisciplinary group of researchers from different disciplines (biology, ecology, economics, and law) that deal with key dimensions of marine social–ecological systems. Particularly, the local and global seafood provision; the feasibility and management of marine protected areas; the use of marine ecosystem services; the institutional dimension in European fisheries, and the affordable models for providing scientific advice to small-scale fisheries. This Special Issue presents key findings from selected case studies around the world available to educators, policy makers, and the technical community. Together, these papers show that a range of diverse ecological, economic, social, and institutional components often mutually interact at spatial and temporal scales, which evidence that managing marine social–ecological systems needs a continuous adaptability to navigate into new governance systems.     

Size and Concentration Measurements of Particles Produced in Commercial Chromium Plating Processes

Abstract

Optical measurements of particle size and concentration were made at the chromium plating tank and exhaust system at a commercial hexavalent chromium plating facility. Particles were examined at three locations in the exhaust system: 1) directly at the hexavalent chromium plating bath surface, 2) at the exit of a cyclone separator located in the exhaust system approximately three to four meters downstream of the bath, and 3) in the exhaust stack, downstream of the induced draft fan and all abatement devices. Particle diameters at the bath surface ranged from 0.3 to 25 μm. Downstream of the cyclone exit and mesh pad filters, particle top sizes were approximately 5 and 0.7 mm, respectively. On a mass basis, the collection efficiency of all abatement devices was 99.997%. Assuming that droplets in the flow consist primarily of water and chromium, correcting the total particle mass flow against water content gives a chromium emission rate of 64,000 μg/hr, which compares favorably with a value of 77,000 μg/hr measured with EPA methods. This initial agreement, which should be validated through additional measurements over a broad range of flow conditions, raises the possibility of continuous monitoring for chromium metal emissions using particle size/mass as a surrogate.     

Thymol as an alternative to pesticides: persistence and effects of Apilife Var on the phototactic behavior of the honeybee Apis mellifera

Thymol is a natural substance increasingly used as an alternative to pesticides in the fight against the Varroa destructor mite. Despite the effectiveness of this phenolic monoterpene against Varroa, few articles have covered the negative or side effects of thymol on bees. In a previous study, we have found an impairment of phototaxis in honeybees following application of sublethal doses of thymol—lower or equal to 100 ng/bee—under laboratory conditions. The present work shows the same behavioral effects on bees from hives treated with Apilife Var®, a veterinary drug containing 74 % thymol, with a decrease in phototactic behavior observed 1 day after treatment. Thus, thymol causes disruption of bee phototactic behavior both under laboratory conditions as well as in beehives. The bee exposure dose in treated hives was quantified using gas chromatography coupled to mass spectrometry (GC–MS), giving a median value of 4.3 μg per body 24 h after treatment, with 11 ng in the brain. The thymol level in 20 organic waxes from hives treated with Apilife Var® was also measured and showed that it persists in waxes (around 10 mg/kg) 1 year after treatment. Thus, in the light of (1) behavioral data obtained under laboratory conditions and in beehives, (2) the persistence of thymol in waxes, and (3) the high load on bees, it would appear important to study the long-term effects of thymol in beehives.     

A link between eumelanism and calcium physiology in the barn owl

In many animals, melanin-based coloration is strongly heritable and is largely insensitive to the environment and body condition. According to the handicap principle, such a trait may not reveal individual quality because the production of different melanin-based colorations often entails similar costs. However, a recent study showed that the production of eumelanin pigments requires relatively large amounts of calcium, potentially implying that melanin-based coloration is associated with physiological processes requiring calcium. If this is the case, eumelanism may be traded-off against other metabolic processes that require the same elements. We used a correlative approach to examine, for the first time, this proposition in the barn owl, a species in which individuals vary in the amount, size, and blackness of eumelanic spots. For this purpose, we measured calcium concentration in the left humerus of 85 dead owls. Results showed that the humeri of heavily spotted individuals had a higher concentration of calcium. This suggests either that plumage spottiness signals the ability to absorb calcium from the diet for both eumelanin production and storage in bones, or that lightly spotted individuals use more calcium for metabolic processes at the expense of calcium storage in bones. Our study supports the idea that eumelanin-based coloration is associated with a number of physiological processes requiring calcium.     

Negative relationship between dispersal distance and demography in butterfly metapopulations

Little is known about the connection between demography and dispersal in metapopulations. The meta-analysis of the population time series of five butterfly species indicated that (meta)population dynamics are driven by density-dependent factors. Inter-specific comparison reveals a significant inverse relationship between population growth rate and the magnitude of dispersal distance. As the range of dispersal distances is constrained by the patch system, dispersing individuals moving too far away would (probably) get lost. This generates selective pressures on individuals with a high dispersal propensity, but favors individuals investing more in reproduction and results in a higher (meta)population growth rate. From a conservation perspective, individuals from (meta)populations and species sacrificing dispersal for the sake of reproductive performances are most vulnerable because of their higher sensitivity to stochastic events: the temporal variation of growth rate was much higher in the two metapopulations where dispersal was limited.