Les hivers plus chauds affectent les traits de vie et le stockage des réserves énergétiques chez un insecte aquatique mais pas la sensibilité à un pesticide largement répandu

International audienceDespite the increased attention for the effects of pesticides under global warming no studies tested how winter warming affects subsequent sensitivity to pesticides. Winter warming is expected to cause delayed negative effects when it increases metabolic rates and thereby depletes energy reserves. Using a common-garden experiment, we investigated the combined effect of a 4°C increase in winter temperature and subsequent exposure to chlorpyrifos in the aquatic larvae of replicated low- and high-latitude European populations of the damselfly Ischnura elegans. The warmer winter (8°C) resulted in a higher winter survival and higher growth rates compared to the cold winter (4°C) commonly experienced by European high-latitude populations. Low-latitude populations were better at coping with the warmer winter, indicating thermal adaptation to the local winter temperatures. Subsequent chlorpyrifos exposure at 20°C induced strong negative effects on survival, growth rate, lipid content and acetylcholinesterase activity while phenoloxidase activity increased. These pesticide effects were not affected by winter warming.Our results suggest that for species where winter warming has positive effects on life history, no delayed effects on the sensitivity to subsequent pesticide exposure should be expected

Conventional settling for the treatment of urban stormwaters in separate sewer systems

Stormwater from separate sewer networks in two urban and peri-urban watersheds was analysed to establish the concentrations of contaminants it contains, together with the distribution of dissolved and particulate pollutants. Furthermore, sedimentation of suspended solids (SS) and pollutants in these effluents was assessed by using two protocols currently applied in France: VICAS and VICPOL. Concentrations of SS are higher on Grigny (peri-urban site), whereas trace metal concentrations are lower. The distribution between dissolved phase and particulate phase pollutants follows the same trend on both sites. A non-negligible part of organic contamination and zinc and nickel contamination was found in the dissolved fraction. Median settling velocities measured for SS vary between 0.40 and 0.72 m/h for Tolbiac (urban site) and 0.52 and 1.96 m/h for Grigny (peri-urban site). At the two sites, the settling velocities for contaminants differ significantly from one rain event to another and can be very much lower than those of suspended solids. These results contribute to determine the settling times needed, as a function of the height to which settling basins are filled, to attain statutory objectives in SS reduction

Caractérisation du fonctionnement d'un ouvrage de stockage-décantation en ligne des eaux pluviales Cas de la galerie Tolbiac-Masséna

National audienceFew data are available on the efficiency of on-line stormwater settling tanks. A study was conducted in 2008 on the Tolbiac-Massena storage system in Paris in order to evaluate the contamination level and the settlability of the collected stormwater, and to analyse the efficiency of the on-line treatment system. Moreover, in situ turbidity data was used to analyse the dynamics of sediment transport over the different sequences of a storage/discharge event. Observed settling efficiencies ranged from 40% to 60% for SS. The SS settling velocities measured in this study were lower than the settling velocity used for the conception of the tank. This result could explained the limited efficiencies observed. Moreover, the perturbations induced by permanent inflow and by the resuspensions during the discharge of the treated water could contribute to a large extent to the weak efficiency

Utilisation de Gammarus sp. en écotoxioclogie. Etude de cas avec l'insecticide régulateur de croissance fénoxycarbe

International audienceGammarus sp. (Amphipoda) are widely distributed across European freshwater systems. In the present study, we evaluated the effect of a fenoxycarb exposure on Gammarus sp.. More specifically, i) we assessed the sensitivity of the embryo stage, ii) we identified embryogenesis' sensitive period, iii) we evaluated the sensitivity of the reproductive period and iv) we compared the response to fenoxycarb exposure among three European gammarid species. Fenoxycarb is a growth regulator insecticide, analog of the insect juvenile hormone, used for pest management and for veterinary purpose. This study demonstrated that 5 and 50 µg

When male heterosexual leaders politicize gender and sexual issues: The logic of representation in the 2014 Bordeaux municipal election campaign

Gender and sexual politics were major issues during the 2014 French municipal elections campaign. A few weeks before the election, France experienced large-scale campaigns against gay marriage and gender equality policies. The aim of this article is to question the relationship between descriptive and substantive representation in the context of the municipal election campaign in Bordeaux. In the context of the 'demo for all', the return of a religious-based opposition between 'moral order and permissive-ness' calls for further investigation. This article thus offers an original point of view based on fieldwork at the municipal level and polling data.Les territoires de l'élection, genre, religion et politiques locales. Un approche comparée (France XXe-XXIe siècle