Does female aggression prevent polygyny? An experiment with pied flycatchers (Ficedula hypoleuca)

The female aggression hypothesis states that resident females may be able to prevent polygyny by behaving aggressively towards intruding females. A critical test of the hypothesis is to provide prospecting females with a choice between displaying mated males some of which have initial mates with artificially reduced levels of aggressiveness. Here we present a mate choice experiment on pied flycatchers Ficedula hypoleuca. The species is a cavity nester, and resident females were prevented from behaving aggressively by enclosing them within their own nestboxes: narrowing the entrance hole so that they could not escape but could still let their head out and have some contact with their mate. This treament had only a minor influence on male behaviour. We studied whether the experimental males were better able to attract a new female than a control group of mated males. Four predictions from the female aggression hypothesis were supported. (1) Mating success of control males was positively related to the distance between their primary and secondary territory. (2) For experimental males, mating success was unrelated to interterritorial distance. (3) Experimental males had higher mating success than control males when the interterritorial distance was short but (4) not when it was long. Experimental males had much lower mating success than unmated males, as would be expected if prospecting females are able to discover male mating status from cues other than visits by primary females to their mates' secondary nest sites. Received: 5 January 1998 / Accepted after revision: 30 December 1998     

<Emphasis Type="Italic">Eubacterium rangiferina</Emphasis>, a novel usnic acid-resistant bacterium from the reindeer rumen

Reindeer are able to eat and utilize lichens as an important source of energy and nutrients. In the current study, the activities of antibiotic secondary metabolites including usnic, antranoric, fumarprotocetraric, and lobaric acid commonly found in lichens were tested against a collection of 26 anaerobic rumen bacterial isolates from reindeer (Rangifer tarandus tarandus) using the agar diffusion method. The isolates were identified based on their 16S ribosomal ribonucleic acid (rRNA) gene sequences. Usnic acid had a potent antimicrobial effect against 25 of the isolates, belonging to Clostridiales, Enterococci, and Streptococci. Isolates of Clostridia and Streptococci were also susceptible to atranoric and lobaric acid. However, one isolate (R3_91_1) was found to be resistant to usnic, antranoric, fumarprotocetraric, and lobaric acid. R3_91_1 was also seen invading and adhering to lichen particles when grown in a liquid anaerobic culture as demonstrated by transmission electron microscopy. This was a Gram-negative, nonmotile rod (0.2-0.7 x 2.0-3.5 microm) with a deoxyribonucleic acid G + C content of 47.0 mol% and main cellular fatty acids including 15:0 anteiso-dimethyl acetal (DMA), 16:0 iso-fatty acid methyl ester (FAME), 13:0 iso-3OH FAME, and 17:0 anteiso-FAME, not matching any of the presently known profiles in the MIDI database. Combined, the phenotypic and genotypic traits including the 16S rRNA gene sequence show that R3_91_1 is a novel species inside the order Clostridiales within the family Lachnospiraceae, for which we propose the name Eubacterium rangiferina. This is the first record of a rumen bacterium able to tolerate and grow in the presence of usnic acid, indicating that the rumen microorganisms in these animals have adapted mechanisms to deal with lichen secondary metabolites, well known for their antimicrobial and toxic effects.     

Production of DMSP and DMS during a mesocosm study of an Emiliania huxleyi bloom: influence of bacteria and Calanus finmarchicus grazing

We investigated the influence of bacteria and metazooplankton on the production of dimethylsulfoniopropionate (DMSP) and dimethylsulfide (DMS) during blooms of Emiliania huxleyi (Lohmann) Hay and Mohler in seawater mesocosms. The phytoplankton succession was marked by the rapid collapse of an initial Skeletonema costatum (Greville) Cleve bloom followed by a small E. huxleyi bloom. The collapse of the diatom bloom was accompanied by an increase in concentrations of dissolved DMSP (DMSP_d) and bacterial abundance and activity (as determined by the thymidine incorporation technique). The increase in bacterial activity was followed by a rapid decrease in DMSP_d concentrations which remained low for the rest of the experiment, even during the subsequent collapse of the E. huxleyi blooms. The absence of DMSP_d and DMS peaks during the declining phase of the E. huxleyi blooms was attributed to the high bacterial activity prevailing at that time. The influence of metazooplankton grazing on DMSP and DMS production was investigated by adding moderate (24 mg dry weight m^-3) and high (520 mg dry weight m^-3) concentrations of Copepodite Stage V and adults of Calanus finmarchicus to two of four filtered (200 m mesh net) enclosures during the E. huxleyi blooms. The addition of C. finmarchicus, even in high concentrations, had no apparent effect on the dynamics of E. huxleyi, suggesting that the copepods were not grazing significantly on nanophytoplankton. The addition of copepods in high concentrations favored an accumulation of chlorophyll a and particulate DMSP. These results suggest that copepods were preying on the herbivorous microzooplankton which, in turn, was controlling the biomass of nanophytoplankton. DMS production was also enhanced in the enclosure with maximum metazooplankton biomass, suggesting that the grazing of C. finmarchicus on microzooplankton containing DMSP may contribute to DMS production. These results provide strong support to the emerging idea that bacteria and metazooplankton grazing play a dominant role in determining the timing and magnitude of DMS pulses following phytoplankton blooms.     

Egg buoyancy variability in local populations of Atlantic cod (Gadus morhua)

Previous studies have found strong evidences for Atlantic cod (Gadus morhua) egg retention in fjords, which are caused by the combination of vertical salinity structure, estuarine circulation, and egg specific gravity, supporting small-scaled geographical differentiations of local populations. Here, we assess the variability in egg specific gravity for selected local populations of this species, that is, two fjord-spawning populations and one coastal-spawning population from Northern Norway (66–71°N/10–25°E). Eggs were naturally spawned by raised broodstocks (March to April 2009), and egg specific gravity was measured by a density-gradient column. The phenotype of egg specific gravity was similar among the three local populations. However, the associated variability was greater at the individual level than at the population level. The noted gradual decrease in specific gravity from gastrulation to hatching with an increase just before hatching could be a generic pattern in pelagic marine fish eggs. This study provides needed input to adequately understand and model fish egg dispersal.     

Modeling of Combined Aerosol and Photooxidant Processes in the Mediterranean Area

The combined UAM-AERO/RAMS modeling system has been applied to study the dynamics of photochemical gaseous species and particulate matter processes in the eastern Mediterranean area between the Greek mainland and the island of Crete. In particular, the modeling system is applied to simulate atmospheric conditions for two periods, i.e., 13-16 July 2000 and 26-30 July 2000. The spatial and temporal distributions of both gaseous and particulate matter pollutants have been extensively studied together with the identification of major emission sources in the area. New pre-processors were developed for the UAM-AERO model for evaluating detailed emission inventories for biogenic compounds, resuspended dust and sea salt. Comparison of the modeling results with measured data was performed and satisfactory agreement was found for a number of gaseous species. However, the model underestimates the PM₁₀ measured concentrations during summer. This is mainly due to the considerable underestimation of particulate matter emissions and in particular dust resuspension, the effect of forest fire emissions and the contribution of Saharan dust episodes.     

The master plan for the management of watercourses in Norway

Summary By 1980 approximately 60% of the total hydro-power potential of 174 TWh in Norway had been developed. The Government therefore found it essential to consider the exploitation of the remaining watercourses in terms of a larger perspective, contrary to the earlier project-by-project policy. This led to the preparation of a Master Plan for Water Resources, a national management plan based on a set of economic, social and environmental considerations. The Master Plan covers 310 watercourses and 770 hydro-power project alternatives.The Master Plan states which projects should be considered first for a licence when development is necessary. It also specifies which watercourses should preferably be reserved for other uses than hydro-power development. In spring of 1985 the Master Plan was presented to Parliament and approved.Svein Halvorsen graduated at the University of Tromsø with a degree in Ecology. He is currently employed as an Engineer at the Norwegian Ministry of Environment at the Department of Natural Resources, where he has been involved in water resources planning and the Norwegian Master Plan.     

Managers’ attitudes towards safety measures in the commercial road transport sector

Safety measures and related costs and benefits have been widely discussed and analysed in academic circles and by the authorities and industrial sectors. The study reported in this paper addresses these aspects from a cognitive based perspective. Risk management is about dealing with the conflict between production and safety. Enterprises which spend too much on safety will meet bankruptcy, and those not concerned with safety measures will meet with severe accidents and related damage. Inspired by James Reason’s theoretical framework, managers (n = 106) of commercial transport enterprises were asked about their attitudes towards safety management, what factors have contributed and their belief that further effort and investments in health, environment and safety (HES) measures will pay off. One half of the managers perceive HES work as too expensive and approximately one quarter assess mandatory HES work as compromising their competitiveness. One third of the managers do not find further safety measures than those already implemented necessary or remunerative. They claim that there are no other alternative ways of doing their activities and that there are no technical measures available that could meet outstanding safety challenges. Managers do acknowledge HES work as important for the reputation of the enterprise. The factor analysis gave five HES attitude factors: (I) concerned with formalities, (II) HES work improves health, environment and safety, (III) HES work is ineffective, (IV) HES regulation is appropriate, and (V) HES work can be improved.     

Seasonal variation in the levels of organohalogen compounds in herring (Clupea harengus) from the Norwegian Sea

The Norwegian spring spawning (NSS) herring is an ecologically important fish stock in the Norwegian Sea, and with a catch volume exceeding one million tons a year it is also economically important and a valuable food source. In order to provide a baseline of the levels of contaminants in this fish stock, the levels of organohalogen compounds were determined in 800 individual herring sampled at 29 positions in the Norwegian Sea and off the coast of Norway. Due to seasonal migration, the herring were sampled where they were located during the different seasons. Concentrations of dioxins and dioxin-like PCBs, non-dioxin-like PCBs (PCB₇) and PBDEs were determined in fillet samples of individual herring, and found to be relatively low, with means (min-max) of 0.77 (0.24-3.5) ng TEQ kg⁻¹ wet weight (ww), 5.0 (1.4-24) μg kg⁻¹ ww and 0.47 (0.091-3.1) μg kg⁻¹ ww, respectively. The concentrations varied throughout the year due to the feeding- and spawning cycle: Starved, pre-spawning herring caught off the Norwegian coast in January-February had the highest levels and those caught in the Norwegian Sea in April-June, after further starvation and spawning, had the lowest levels. These results show that the concentrations of organohalogen compounds in NSS herring are relatively low and closely tied to their physiological condition, and that in the future regular monitoring of NSS herring should be made in the spawning areas off the Norwegian coast in late winter.