Low paternity in the hornet Vespa crabro indicates that multiple mating by queens is derived in vespine wasps

Queen mating frequency was studied in the European hornet, Vespa crabro, by analyzing four DNA microsatellite loci in 20 workers from each of 14 nests. Queens were found to be predominantly singly mated (9/14), although double (4/14) and triple mating (1/14) also occurred. For most multiply mated queens, paternity was significantly biased with the majority male fathering on average 80% of the female offspring. The population-wide effective mating frequency was therefore low (1.11), and sister-sister relatedness high (0.701 ± 0.023 SE). Low effective mating frequency in Vespa, in combination with data from other vespines, suggests that high paternity frequency is derived in the group. Some problems with the non-detection of fathers, where the queen was not sampled or shared alleles with males, are analyzed. Received: 16 November 1998 / Received in revised form: 29 March 1999 / Accepted: 12 April 1999     

Amino acid metabolism and protein turnover in larval turbot (Scophthalmus maximus) fed natural zooplankton or Artemia

The present paper studied the influence of different food regimes on the free amino acid (FAA) pool, the rate of protein turnover, the flux of amino acids, and their relation to growth of larval turbot (Scophthalmus maximus L.) from first feeding until metamorphosis. The amino acid profile of protein was stable during the larval period although some small, but significant, differences were found. Turbot larvae had proteins which were rich in leucine and aspartate, and poor in glutamate, suggesting a high leucine requirement. The profile of the FAA pool was highly variable and quite different from the amino acid profile in protein. The proportion of essential FAA decreased with development. High contents of free tyrosine and phenylalanine were found on Day 3, while free taurine was present at high levels throughout the experimental period. Larval growth rates were positively correlated with taurine levels, suggesting a dietary dependency for taurine and/or sulphur amino acids. Reduced growth rates in Artemia-fed larvae were associated with lower levels of free methionine, indicating that this diet is deficient in methionine for turbot larvae. Leucine might also be limiting turbot growth as the different diet organisms had lower levels of this amino acid in the free pool than was found in the larval protein. A previously presented model was used to describe the flux of amino acids in growing turbot larvae. The FAA pool was found to be small and variable. It was estimated that the daily dietary amino acid intake might be up to ten times the larval FAA pool. In addition, protein synthesis and protein degradation might daily remove and return, respectively, the equivalent of up to 20 and 10 times the size of the FAA pool. In an early phase (Day 11) high growth rates were associated with a relatively low protein turnover, while at a later stage (Day 17), a much higher turnover was observed. Received: 19 March 1997 / Accepted: 14 April 1997     

Hotspots of Epiphytic Lichen Diversity in Two Young Managed Forests

Understanding within-stand variation in diversity of epiphytes will provide an improved basis for producing timber while conserving biological diversity. Two 80-ha, 50–year–old managed stands of conifers were surveyed to locate 0.4 ha putative "diversity" plots, the areas appearing most diverse in lichen epiphytes. These plots were generally located in areas made heterogeneous by canopy gaps, wolf trees (trees with large-diameter lower branches), and old-growth remnant trees. "Matrix" plots, in contrast, were chosen at random from the remaining, more homogenous forest. Diversity plots hosted from 25% to 40% more epiphytic lichen species than matrix plots in both stands. The strongest within-stand gradients in species composition were correlated with percentage of plot occupied by gaps and wolf trees. Percentage of the plot in gaps was correlated with species richness (r = 0.79). In the more structurally diverse stand, diversity and abundance of nitrogen-fixing "cyanolichens" were correlated with percentage of the plot occupied by gaps (0.5 < r < 0.9), and alectorioid lichens were correlated with percentage of the plot occupied by old-growth remnant trees (0.5 < r < 0.6). In the stand with more homogenous structure, percentage of the plot under gaps was correlated with regionally common species that were otherwise absent or sparse in the matrix. Protecting gaps, hardwoods, wolf trees, and old-growth remnant trees during thinning or other partial cutting is likely to promote the majority of epiphytic macrolichens in young conifer forests. Because these features are easily recognized on aerial photos and on the ground by land managers, it is practical to manage for forest structures that would promote lichen diversity.     

Extra-pair paternity and the opportunity for sexual selection in a socially monogamous bird (Dendroica petechia)

We used multi-locus DNA fingerprinting to characterise the genetic mating system of the socially monogamous yellow warbler (Dendroica petechia). Over 2 years there were no instances of brood parasitism, but 59% of families (n = 90) contained extrapair sired young and 37% of offspring (n = 355) were of extra-pair paternity. Most hypotheses for extra-pair mating in monogamous species assume a paternity benefit to extra-pair sires, and focus on the benefit(s) to females. However, the assumption of male benefit has been little tested. Among yellow warblers, known extra-pair sires were just as likely to be cuckolded as any male in the population, and there was at least one reciprocal exchange of extra-pair paternity. Nevertheless, among known extra-pair sires, the paternity gains from extra-pair paternity were, on average, greater than the losses in their own families. These results show there is a paternity benefit to certain males. However, the benefit is not absolute but relative and therefore more difficult to measure. The results also suggest that patterns of extra-pair fertilisation are not determined by female choice alone. Most confirmed extra-pair mates were territorial neighbours, but some resided as far as three territories apart, and greater spatial separation was implied in other cases. Thus, the opportunity for extra-pair mating is great. We estimate that as a result of extra-pair fertilisations, variance in male mating success is increased somewhere between 3-fold and 15-fold over that which would result from within-pair reproduction alone. These findings affirm the potential importance of extra-pair reproduction for sexual selection in monogamous species and they support earlier suggestions that extra-territorial forays by male yellow warblers are for the purpose of extra-pair mating.     

Fate of saline ions in a planted landfill site with leachate recirculation

Recirculation of leachate on a covered landfill site planted with willows or other highly evapotranspirative woody plants is an inexpensive option for leachate management. In our study, a closed landfill leachate recirculation system was established on a rehabilitated municipal solid waste landfill site with planted landfill cover. The main objective of the study was to evaluate the sustainability of the system with regard to high hydraulic loads of the landfill leachate on the landfill cover and high concentrations of saline ions, especially potassium (K⁺), sodium (Na⁺) and chloride (Cl^?), in leachate.The results of intensive monitoring, implemented during May 2004 and September 2007, including leachate, soil and plant samples, showed a high sustainability of the system regarding saline ions with the precipitation regime of the studied region. Saline ion concentrations in leachates varied between 132 and 2592 mg Cl^? L^?1, 69 and 1310 mg Na⁺ L^?1 and between 66 and 2156 mg K⁺ L^?1, with mean values of 1010, 632 and 686 mg L^?1, respectively. Soil salinity, measured as soil electrical conductivity (EC), remained between 0.17 and 0.38 mS cm^?1 at a depth between 0 and 90 cm. An average annual precipitation of 1000 mm provided sufficient leaching of saline ions, loaded by irrigation with landfill leachate, from the soil of the landfill cover and thus prevented possible salinity shocks to the planted willows.     

Modelling of stable isotope fractionation by methane oxidation and diffusion in landfill cover soils

A technique to measure biological methane oxidation in landfill cover soils that is gaining increased interest is the measurement of stable isotope fractionation in the methane. Usually to quantify methane oxidation, only fractionation by oxidation is taken into account. Recently it was shown that neglecting the isotope fractionation by diffusion results in underestimation of the methane oxidation. In this study a simulation model was developed that describes gas transport and methane oxidation in landfill cover soils. The model distinguishes between (12)CH(4), (13)CH(4), and (12)CH(3)D explicitly, and includes isotope fractionation by diffusion and oxidation. To evaluate the model, the simulations were compared with column experiments from previous studies. The predicted concentration profiles and isotopic profiles match the measured ones very well, with a root mean square deviation (RMSD) of 1.7vol% in the concentration and a RMSD of 0.8 per thousand in the delta(13)C value, with delta(13)C the relative (13)C abundance as compared to an international standard. Overall, the comparison shows that a model-based isotope approach for the determination of methane oxidation efficiencies is feasible and superior to existing isotope methods.     

The contemporary cement cycle of the United States

A country-level stock and flow model for cement, an important construction material, was developed based on a material flow analysis framework. Using this model, the contemporary cement cycle of the United States was constructed by analyzing production, import, and export data for different stages of the cement cycle. The United States currently supplies approximately 80% of its cement consumption through domestic production and the rest is imported. The average annual net addition of in-use new cement stock over the period 2000–2004 was approximately 83 million metric tons and amounts to 2.3 tons per capita of concrete. Nonfuel carbon dioxide emissions (42 million metric tons per year) from the calcination phase of cement manufacture account for 62% of the total 68 million tons per year of cement production residues. The end-of-life cement discards are estimated to be 33 million metric tons per year, of which between 30% and 80% is recycled. A significant portion of the infrastructure in the United States is reaching the end of its useful life and will need to be replaced or rehabilitated; this could require far more cement than might be expected from economic forecasts of demand for cement.