Semiochemicals mediating host-finding behaviour in the phoretic association between Macrocheles saceri (Acari: Mesostigmata) and Scarabaeus species (Coleoptera: Scarabaeidae)

Summary. Phoresy is an interspecific association where mobile organisms ensure small and/or wingless organisms to colonize patchy distributed environment. Macrocheles saceri (Acari: Mesostigmata) is a phoretic mite which specialized on Scarabaeus dung beetles (Coleoptera: Scarabaeidae). Variation for phoretic load and sites for mite fixation on beetle body has been tested according to Scarabaeus species. The number of setae on beetle body cannot explain the observed patterns in mite fixation. Evidence was provided that the semiochemicals of the host cuticle play a kairomonal role in the host finding behaviour of phoretic mites. In addition semiochemicals ensure host discrimination.     

Conservative maternal care in an iteroparous mammal: a resource allocation experiment

When resources are limited, life history theory predicts a trade-off between growth, reproduction and survival. In summer, lactating females of temperate large herbivores such as the white-tailed deer (Odocoileus virginianus) normally have access to abundant forage but also face the high energetic needs of lactation and recovery from winter mass loss. At high population density, however, females may face a trade-off between allocating resources for maintenance and for reproduction. To simulate the effects of increased intra-specific competition at high density, we measured for 2 years how an experimental food restriction of approximately 20% affected current reproduction and body mass changes of adult females and their fawns during the fawning and lactation periods. Fawn survival decreased 35%, and fawn growth decreased 26% in the food-restricted treatment. There was no effect of food restriction on female mass. Irrespective of treatment, however, lactating females gained 30 g/day less than non-lactating females, and females that had weaned a fawn the previous year gained 20 g/day less than females that had not. We conclude that when resources were scarce, females adopted a conservative strategy favouring their own survival, mass recovery and future reproductive potential over their current reproduction, probably to maximise their lifetime reproductive success.     

Pheromones inBlattella germanica andBlaberus craniifer (Blaberoidea): Glandular source,morphology and analyses of pheromonally released behaviours

Females ofBlattella germanica andBlaberus craniifer produce a volatile sex pheromone attractive at a distance for conspecific males. During the emission of the pheromone, females ofB. craniifer adopt a typical calling posture; we never observe such a stance inB. germanica females. For both species, the glandular structures responsible for pheromonal production are located on the female pygidium. InB. germanica, the thickness of the glandular epithelium is clearly correlated with the attractiveness of females, being maximum for 13 day old females. The functions of the pygidial glands are discussed in both species.     

Land district,ecophysiographic units and areas: The landscape mapping of the Ministère des Ressources naturelles du Québec

In 1985, the Ministère des Ressources naturelles established a Forest Ecological Survey Program for Southern Québec. One component of the program was the mapping of land districts, which provide a physiographically-based territorial reference system. The land districts have an average surface area of between 100 and 300 sq km. Since its inception, the department has further refined the methodologies and standardized the results. The current methodologies are based on inventory and analysis of the geographical distribution of permanent environmental components (e.g., relief, surficial deposits, geology, hydrography). The products include 1:50 000 maps of surficial deposits, 1:250 000 maps of the land districts and physiographic systems, and a computerized data bank.To date, 500 000 km square have been covered, and the estimated completion date for the work is 1999. To facilitate use of the products and to encourage the development of new applications, a guide for forest managers and other users has been recently published. The guide assists with forest management planning strategies based upon the physical environment, in particular the production and use of interpretation grids and maps. The products of the mapping process are, for many regions of Southern Québec, the only source of information on permanent environmental components.Currently, the Ministère des Ressources naturelles is planning to develop landscape maps of Southern Québec which identify ecophysiographic units (1:1 250 000) and ecophysiographic areas (1:2 500 000). These maps are based upon the integration of critical physiographic features and the synthesis of land regions.     

Ocean acidification and temperature rise: effects on calcification during early development of the cuttlefish Sepia officinalis

This study investigated the effects of seawater pH (i.e., 8.10, 7.85 and 7.60) and temperature (16 and 19 °C) on (a) the abiotic conditions in the fluid surrounding the embryo (viz. the perivitelline fluid), (b) growth, development and (c) cuttlebone calcification of embryonic and juvenile stages of the cephalopod Sepia officinalis. Egg swelling increased in response to acidification or warming, leading to an increase in egg surface while the interactive effects suggested a limited plasticity of the swelling modulation. Embryos experienced elevated pCO₂ conditions in the perivitelline fluid (>3-fold higher pCO₂ than that of ambient seawater), rendering the medium under-saturated even under ambient conditions. The growth of both embryos and juveniles was unaffected by pH, whereas ⁴⁵Ca incorporation in cuttlebone increased significantly with decreasing pH at both temperatures. This phenomenon of hypercalcification is limited to only a number of animals but does not guarantee functional performance and calls for better mechanistic understanding of calcification processes.     

Biomonitoring of traffic-related nitrogen oxides in the Maurienne valley (Savoie, France), using purple moor grass growth parameters and leaf N/N ratio

Effects of traffic-related nitrogenous emissions on purple moor grass (Molinia caerulea (L.) Moench) transplants, used here as a new biomonitoring species, were assessed along 500 m long transects orthogonal to roads located in two open areas in the Maurienne valley (French Alps). Leaves were sampled during summer 2004 and 2005 for total N-content and ¹⁵N-abundance determination while nitrogen oxides (NO and NO₂) concentrations were determined using passive diffusion samplers. A significant and negative correlation was observed between plant total N-content, and ¹⁵N-abundance and the logarithm of the distance to the road axis. The strongest decreases in plant N parameters were observed between 15 and 100 m from road axis. They were equivalent to background levels at a distance of about 800 m from the roads. In addition, motor vehicle pollution significantly affected vegetation at road edge, as was established from the relationship between leaf ¹⁵N-abundance, total N-content and road traffic densities.     

高盐工业废水人工湿地处理中植物的筛选

通过人工湿地中试实验,考察了芦苇、睡莲、水葱、狭叶香蒲和宽叶香蒲水生植物单元对经生化处理的石油和精细化工工业区的工业废水中盐含量较高、氮磷营养盐含量较低和化学需氧量(COD)含量较高的废水中污染物的去除情况,研究了在植物不同生长阶段系统中COD的去除同盐度之间的关系,探讨了盐度差异对植物生长状况的影响,为确定人工湿地适合的进水盐度,达到有效去除高含盐量工业废水中有机污染物提供依据。结果表明,芦苇、睡莲和狭叶香蒲3种植物单元内高含盐量工业废水中污染物的净化效果较水葱和宽叶香蒲单元的净化效果好:前3种植物单元内COD、生化需氧量(BOD)和总磷(TP)的去除率大约在38%、55%和62%左右,而水葱和宽叶香蒲2种植物单元内COD、BOD和TP的去除率大约在30%、36%和52%左右;系统中各个单元内总氮(TN)去除率都在85%以上。在植物的不同生长阶段,人工湿地系统中氯离子浓度与COD浓度之间的相关性存在差异:植物生长初期,系统中氯离子浓度与系统中COD浓度之间无显著相关性,而在植物生长旺期和末期,两者则成正相关关系。因此,需根据植物的生长阶段调整人工湿地的进水盐度。     

A Two-Sector Model of Economic Growth with Endogenous Technical Change and Pollution Abatement

Environmental Modeling & Assessment - We provide insights into the relationships between technological development, economic growth, and pollution accumulation using a two-sector model of...     

Ozone production from Grenoble city during the August 2003 heat wave

The heat wave from 1 to 16 August 2003 is considered in the city of Grenoble (French Alps). The modelling system (PREVALP) is based on several models operating on nested domains: MM5 for dynamics, CHIMERE for chemistry (18 km and 6 km grid size) and METPHOMOD for both dynamics and chemistry (2 km grid size). The analysis of the results shows that during the heat wave, the mixing layer is thicker, up to 3500 m agl, hence inducing transport of ozone to high altitude. Two regimes were diagnosed: (1) a freely developing convective layer, (2) a layer trapped under south wind which makes ozone precursors accumulate in the city. Local ozone production is estimated to be 40% of the plume maximum in case (2) and only 30% in case (1). Sensitivity analysis by step increase for temperature at the boundary of the inner domain shows the non-linearity of the response; in this case most of the effect comes from chemistry. By changing biogenic emission significant changes are observed in restricted areas.     

Exposure assessment of French women and their newborn to brominated flame retardants: determination of tri- to deca- polybromodiphenylethers (PBDE) in maternal adipose tissue, serum, breast milk and cord serum

In the frame of a French monitoring program, tri- to deca- polybromodiphenylethers (PBDE) have been measured in maternal and cord serum, adipose tissue, and breast milk samples, collected from 93 volunteer women during caesarean deliveries. The seven major tri- to heptaBDE (BDE-28, 47, 99, 100, 153, 154, and 183) were detected in adipose tissue and breast milk with cumulated median values of 2.59 and 2.51 ng g⁻¹ l w. Nine highly brominated octa- to decaBDE (BDE-196, 197, 201, 202, 203, 206, 207, 208 and 209) was performed in the same samples, with cumulated median values of 2.73 and 3.39 ng g⁻¹ l w in adipose tissue and breast milk, respectively. At this opposite, median levels of octa- to decaBDE in maternal and cord serum appeared significantly higher than the levels of tri- to heptaBDE in the same matrices, i.e. 8.85 and 12.34 versus 0.98 and 0.69 ng g⁻¹ l w, respectively.