Extended family structure in the ant Formica paralugubris: the role of the breeding system

In populations of various ant species, many queens reproduce in the same nest (polygyny), and colony boundaries appear to be absent with individuals able to move freely between nests (unicoloniality). Such societies depart strongly from a simple family structure and pose a potential challenge to kin selection theory, because high queen number coupled with unrestricted gene flow among nests should result in levels of relatedness among nestmates close to zero. This study investigated the breeding system and genetic structure of a highly polygynous and largely unicolonial population of the wood ant Formica paralugubris. A microsatellite analysis revealed that nestmate workers, reproductive queens and reproductive males (the queens' mates) are all equally related to each other, with relatedness estimates centring around 0.14. This suggests that most of the queens and males reproducing in the study population had mated within or close to their natal nest, and that the queens did not disperse far after mating. We developed a theoretical model to investigate how the breeding system affects the relatedness structure of polygynous colonies. By combining the model and our empirical data, it was estimated that about 99.8% of the reproducing queens and males originated from within the nest, or from a nearby nest. This high rate of local mating and the rarity of long-distance dispersal maintain significant relatedness among nestmates, and contrast with the common view that unicoloniality is coupled with unrestricted gene flow among nests. Received: 8 February 1999 / Received in revised form: 15 June 1999 / Accepted: 19 June 1999     

湿式氧化技术的应用现状与发展

湿式氧化技术是上世纪50年代发展起来的一项在高温高压下处理废水的技术。50年来,被广泛地应用于高浓度难降解有机废水和城市污水厂污泥的处理。着重介绍了当今世界上几种主要的湿式氧化工艺的工艺特点及应用现状,为我国湿式氧化技术的工业应用提供参考,并提出了今后的研究重点。     

Biliary PAH metabolites, EROD activity and DNA damage in dab (Limanda limanda) from Seine Estuary (France)

The Seine Estuary is well known to be widely contaminated by organic pollutants and especially by polycyclic aromatic hydrocarbons (PAHs). Fish are known to metabolize PAHs, leading to different toxic effects at both cellular and sub-cellular levels. In this work, we studied the relationships between the 7-ethoxyresorufin-O-deethylase (EROD) activity in the liver, the level of DNA strand breaks in blood cells and the concentration of PAH metabolites in the bile of the sentinel flatfish species Limanda limanda. Muscle and liver samples were analysed for parent PAH levels. Female and male dabs of two size classes (juveniles and adults) were collected by trawling in two sites with different degrees of pollution during March and September 2005 and 2006. Significant effects of sex, age, site and season were demonstrated on EROD activity and the level of strand breaks. Parent PAH concentrations in dabs did not allow discriminating of the two sampling sites. However, for PAH metabolites, significant differences were observed with sites and seasons. Dabs collected at the mouth of the estuary appeared to be the most impacted when looking at the results obtained with the three selected markers. The significant correlations observed between the level of PAH metabolites and the level of DNA lesions showed the importance of a combined analysis of chemical and biochemical markers to correctly assess the contribution of chemical contamination to the toxic effects measured in situ in fish.     

Uranium oxide and other airborne particles deposited on cypress leaves close to a nuclear facility

Enhanced activity of actinides and some decay products has been reported for the leaves of cypress trees (Chamaecyparis nootkatensis) at the edge of the Malvési uranium-processing facility, southwestern France. The enhanced activity is due to the release of actinides via the smokestacks and from artificial ponds inside the facility. This study was conducted to characterize airborne particulate matter deposited on the leaf surfaces and to investigate whether or not radioactive particles may be identified. Air-dried leaf samples were examined by scanning electron microscopy, in combination with energy-dispersive X-ray spectrometry. The samples were scanned systematically in both secondary and backscattered electron modes. Particles ranging in size from <200 nm to ~40 μm were found on most portions of the adaxial leaf surface, but they are especially abundant at the boundary between facial and lateral leaves. The majority of the analyzed particles could be attributed to five principal classes: carbonates, silicates, sulfates, oxides/hydroxides, and halides. In addition, other types of particles were found, including Fe alloys; scheelite-group phases; phosphates; sulfides; and fly ash spheres. Similar particles were also observed on the surface of a wheat sample used for comparison. Of special interest are U-rich particles, which were observed on the cypress leaves only and which were identified as U oxides, except for one particle, which was a U-oxide-fluoride. These U-rich particles were released into the atmosphere by the nuclear facility prior to their deposition on the leaf surfaces. As most of the U-rich particles are <2.5 μm across, they are respirable. Once inhaled, particles containing alpha-emitting isotopes represent a potentially long-term source of ionizing radiation inside the lungs and thus, pose a threat to the health of people living nearby.     

Extra-pair paternity in the monogamous Alpine marmot revealed by nuclear DNA microsatellite analysis

The genetic parentage and pedigrees of 35 litters from 12 family groups of monogamous Alpine marmot (Marmota marmota) in the French Alps were analyzed using six hypervariable sequence repeat nuclear loci (microsatellites). All of the members of these family groups were sampled during a 5-year period. Hairs taken directly from animals served as a source of DNA for amplification of the loci. Our results indicate that the genetic mating system of the Alpine marmot is quite different from a strictly monogamous breeding system. Extra-pair paternity occurred in 11 of the 35 litters (31.4%). Of the 134 juveniles typed, 26 (19.4%) could be attributed to extra-pair copulation (EPC). We examine hypotheses which could explain the evolution of EPC and discuss the different patterns of extra-pair mating. Received: 11 July 1997 / Accepted after revision: 23 May 1998     

X-ray absorption and photoelectron spectroscopy investigation of selenite reduction by FeII-bearing minerals

The long-lived radionuclide 79Se is one of the elements of concern for the safe storage of high-level nuclear waste, since clay minerals in engineered barriers and natural aquifer sediments strongly adsorb cationic species, but to lesser extent anions like selenate (SeVIO4(2-)) and selenite (SeIVO3(2-)). Previous investigations have demonstrated, however, that SeIV and SeVI are reduced by surface-associated FeII, thereby forming insoluble Se0 and Fe selenides. Here we show that the mixed FeII/III (hydr)oxides green rust and magnetite, and the FeII sulfide mackinawite reduce selenite rapidly (< 1 day) to FeSe, while the slightly slower reduction by the FeII carbonate siderite produces elemental Se. In the case of mackinawite, both S(-II) and FeII surface atoms are oxidized at a ratio of one to four by producing a defective mackinawite surface. Comparison of these spectroscopic results with thermodynamic equilibrium modeling provides evidence that the nature of reduction end product in these FeII systems is controlled by the concentration of HSe(-); Se0 forms only at lower HSe(-) concentrations related to slower HSeO3(-) reduction kinetics. Even under thermodynamically unstable conditions, the initially formed Se solid phases may remain stable for longer periods since their low solubility prevents the dissolution required for a phase transformation into more stable solids. The reduction by Fe2+-montmorillonite is generally much slower and restricted to a pH range, where selenite is adsorbed (pH < 7), stressing the importance of a heterogeneous, surface-enhanced electron transfer reaction. Although the solids precipitated by the redox reaction are nanocrystalline, their solubility remains below 6.3 x 10(-8) M. No evidence for aqueous metal selenide colloids nor for Se sorption to colloidal phases was found. Since FeII phases like the ones investigated here should be ubiquitous in the near field of nuclear waste disposals as well as in the surrounding aquifers, mobility of the fission product 79Se may be much lower than previously assumed.     

Incest avoidance,fluctuating asymmetry,and the consequences of inbreeding in Iridomyrmex humilis,an ant with multiple queen colonies

Summary Inbreeding may have important consequences for the genetic structure of social insects and thus for sex ratios and the evolution of sociality and multiple queen (polygynous) colonies. The influence of kinship on mating preferences was investigated in a polygynous ant species, Iridomyrmex humilis, which has within-nest mating. When females were presented simultaneously with a brother that had been reared in the same colony until the pupal stage and an unrelated male produced in another colony, females mated preferentially with the unrelated male. The role of environmental colony-derived cues was tested in a second experiment where females were presented with two unrelated males, one of which had been reared in the same colony until the pupal stage (i.e., as in the previous experiment), while the other had been produced in another colony. In this experiment there was no preferential mating with familiar or unfamiliar males, suggesting that colony-derived cues might not be important in mating preferences. Inbreeding was shown to have no strong effect on the reproductive output of queens as measured by the number of worker and sexual pupae produced. The level of fluctuating asymmetry of workers produced by inbreeding queens was not significantly higher than that of non-inbreeding queens. Finally, colonies headed by inbreeding queens did not produce adult diploid males. Based on the current hypotheses of sex-determination the most plausible explanations for the absence of diploid-male-producing colonies are that (i) workers recognized and eliminated these males early in their development, and/or (ii) there are multiple sex-determining loci in this species. It is suggested that even if inbreeding effects on colony productivity are absent or low, incest avoidance mechanisms may have evolved and been maintained if inbreeding queens produce a higher proportion of unviable offspring. Correspondence to: L. Keller at the present address     

Metabolic fate of [14C]-2,4-dichlorophenol in macrophytes

The metabolic fate of 2,4-dichlorophenol (DCP) was investigated in six macrophytes representing different life forms. Salvinia natans and Lemna minor were chosen as surface-floating plants, Glyceria maxima and Mentha aquatica as emergent species and Myriophyllum spicatum and Hippuris vulgaris as submerged aquatic plants. After uptake of a [U-phenyl-14C]-DCP solution followed by a 48 h water chase, whole plants (L. minor, S. natans) or excised shoots were harvested and aqueous extracts were analysed by high performance liquid chromatography (HPLC). Metabolites were then isolated, submitted to enzymatic or chemical hydrolyses and characterised by electrospray ionisation-mass spectrometric analyses. Whereas DCP monoglucosides or more complex monoglucoside esters, either malonyl or acetyl, were found in most species, an unusual glucosyl-pentose conjugate was identified as the DCP major metabolite in L. minor and G. maxima. Our results showed for the first time the ability of five macrophytes to uptake and metabolise DCP and the characterisation of their metabolic pathways of DCP biotransformation.