A contact anti-aphrodisiac pheromone supplied by the spermatophore in the rove beetle Aleochara curtula: mode of transfer and evolutionary significance

By reducing the attractiveness of their mating partner via an anti-aphrodisiac pheromone, males can prevent a remating of the female and thus reduce the risk of sperm competition. For females, the main benefit from allowing the chemical manipulation of their attractiveness is probably the avoidance of sexual harassments from rival males. While mating plugs generally constitute a physical barrier which hinders male mating attempts, chemical manipulations must trustfully inform the responding male of the female's reluctance to mate; otherwise, it would be beneficial to ignore the repellent information. In our experiments, males of the polyandrous rove beetle Aleochara curtula chemically manipulated the attractiveness of their mating partner. Coincident with the deposition of a spermatophore into the female genital chamber, an anti-aphrodisiac pheromone was transferred and readily spread onto the female surface, where it was subsequently perceived by rival males via parameres, the claspers of the male genitalia. Males aborted contact with the mated female to avoid further time- and energy-consuming elements of the mating sequence. The chemical mode of action was demonstrated inter alia by spicing virgin females with spermatophore extracts. The action of the anti-aphrodisiac correlated with the persistence of the spermatophore in the female genital chamber and corresponded to the length of stay of the mated female at a carcass, where the density of rival males is highest. The ensuing benefits for all three parties involved in this communication system, which render this post-copulatory mate guarding strategy evolutionary stable, are discussed.     

A modified method for determination of dehydrogenases activity of activated sludge

Examination of the different methods employed to detect dehydrogenases activity of activated sludge by reduction of triphenyl tetrazolium chloride (TTC) indicated the non‐uniformity of the procedures. A modified method is, therefore, developed which consists of incubation of a dilute sonicated sample of mixed liquor suspended solids (MLSS) of activated sludge with TTC in the presence of sodium sulfite, phosphate buffer and cyanide. Triphenyl formazan (TF) formed is first dissolved in acetic acid and later extracted by toluene. Optical density (OD) of the color is measured at 485 nm. Dehydrogenases activity is calculated from the OD and expressed as specific activity per unit weight of protein. Modified method gave less relative dispersion compared to the values obtained on the same but unsonicated samples of MLSS.     

Performance evaluation of NOAA-EPA developmental aerosol forecasts

To aid air quality model development and assess air quality forecasts, the Meteorological Development Laboratory (MDL) provided categorical verification metrics for developmental aerosol predictions. The National Air Quality Forecasting Capability (NAQFC) generated 48 h (of) gridded hourly developmental predictions for the lower 48 states (CONUS) domain in 12 km horizontal spacing. The NAQFC uses the North American Mesoscale (NAM) model with EPA’s Community Multiscale Air Quality (CMAQ) model to produce predictions of ground level aerosol concentrations. We used bilinear interpolation to calculate predicted daily maximum values at the location of the observation sites. We compared these interpolated predicted values to the observed daily maximum to produce 2 × 2 contingency tables, with a threshold of 40 μg/m³ during the months of March–August, 2007. The model showed some degree of skill in predicting aerosol exceedances. These results are preliminary as the NAQFC model for aerosol prediction is in the developmental stage. A more comprehensive performance evaluation will be accomplished in 2008, when more data become available. Our verification metrics included categorical analyses for Fraction Correct (FC) or percent correct (FC × 100), Threat Score (TS) or Critical Success Index (CSI), Probability of Detection (POD), and the False Alarm Rate (FAR), Mean Absolute Error (MAE) and mean algebraic error or bias, where bias is forecast minus observation. Graphic products included weekly statistics for the CONUS displayed in the form of bar charts, scatterplots, and graphs. In addition, we split the CONUS into six geographic regions and provided regional statistics on a monthly basis. MDL produced spatial maps of daily 1-h maximum predicted aerosol values overlaid with the corresponding point observations. MDL also provided spatial maps of the daily maximum of the 24-h running average. We derived the 24-h running average from the 1-h average predicted aerosol values and observations.     

Twenty-Six Years of Green Turtle Nesting at Tortuguero, Costa Rica: An Encouraging Trend

The green turtle ( Chelonia mydas ) population that nests at Tortuguero, Costa Rica, is the largest in the Atlantic by at least an order of magnitude. Surveys to monitor the nesting activity on the northern 18 km of the 36-km beach were initiated in 1971 and extended to the entire beach in 1986. From the survey data, we estimated the total number of nesting emergences on the northern 18 km for each year from 1971 through 1996. Evaluation of the trend in nesting emergences indicated a relatively consistent increase from 1971 to the mid-1980s, constant or perhaps decreasing nesting during the late 1980s, and then resumption of an upward trend in the 1990s. Evaluation of trends in sea turtle nesting populations requires many years of data because of the large degree of annual variation in nesting numbers. The trends reported in this study must be evaluated with caution for several reasons. First, if the mean number of nests deposited by each female each year (clutch frequency) varies significantly among years, changes in the number of nesting emergences among years could reflect changes in the number of nesting females, clutch frequency, or both. Second, we only assessed the trend in one segment of the population (mature females), which may or may not represent the trend of the entire green turtle population and which, because of late maturity, may not reflect changes in juvenile mortality for many years. Third, survey frequency, and thus confidence in annual estimates, varied among years. The upward population trend must be assessed from the perspective of the catastrophic decline that the Caribbean green turtle populations have experienced since the arrival of Europeans. If careful management is continued in Costa Rica and adopted throughout the region, the collapse of the Caribbean green turtle populations—which seemed imminent in the 1950s—can be avoided.     

Carbon dioxide capture strategies from flue gas using microalgae: a review

Global warming and pollution are the twin crises experienced globally. Biological offset of these crises are gaining importance because of its zero waste production and the ability of the organisms to thrive under extreme or polluted condition. In this context, this review highlights the recent developments in carbon dioxide (CO₂) capture from flue gas using microalgae and finding the best microalgal remediation strategy through contrast and comparison of different strategies. Different flue gas microalgal remediation strategies discussed are as follows: (i) Flue gas to CO₂ gas segregation using adsorbents for microalgal mitigation, (ii) CO₂ separation from flue gas using absorbents and later regeneration for microalgal mitigation, (iii) Flue gas to liquid conversion for direct microalgal mitigation, and (iv) direct flue gas mitigation using microalgae. This work also studies the economic feasibility of microalgal production. The study discloses that the direct convening of flue gas with high carbon dioxide content, into microalgal system is cost-effective.     

Institutional Responses to Climate Change: the Case of the Alaska Transportation System

Institutions managing the Alaska road,rail, airport, and marine highwaytransportation system and the pipelinecorridor are evaluated for reactions toevidence of climate change. Long-termclimate warming is not a formal criterionin the decisional process of the stateDepartment of Transportation and PublicFacilities for road and airport projects,which have a short (15–25 year) life span,but is taken into account for bridgeconstruction (50–75 year life). Short- tomid-term climate effects are considered inareas with discontinuous permafrost andaffect routing, roadbed construction, andmaintenance decisions. National standardsare amended with Alaska-specific practicesfor unique cold-weather conditions.The Federal/State Joint Pipeline Office(JPO), responsible for monitoring ofpipeline safety under the federal lease andstate grant, in 2001 developed additionalstipulations to mitigate permafrost thawingand slope instability, including a `watchlist' of 200 wobbling VSMs on theTrans-Alaska Pipeline. This action appearsmore responsive to climate change effectsthan that of any other arctic institutionstudied. It can be attributed to thespecific authority of the JPO to monitorgeotechnical conditions at present and inthe future.In general, agencies tended to adoptincremental responses to evidence ofclimate change.     

The effects of mating on infanticide and pup discrimination in white-footed mice

Summary A laboratory study was conducted with white-footed mice (Peromyscus leucopus) to determine (1) if cohabitation and/or successful mating inhibits infanticide, and if so for how long, and (2) if males and females can discriminate between their own (familiar) and strange (unfamiliar) pups. Infanticidal males and females that were paired for 15 days and did not reproduce were not inhibited from killing pups, whereas infanticidal males and females that were paired until they reproduced were inhibited from committing infanticide at 4 days postpartum. Neither males nor females discriminated between familiar and unfamiliar pups with regard to engaging in infanticide. Approximately 50% of wild-caught males and females killed pups in the laboratory. Infanticidal pairs bred significantly sooner than did noninfanticidal pairs. The results are consistent with the promiscuous nature of P. leucopus males and territoriality of P. leucopus females. Offprint requests to: Donna M. Cicirello, Kellogg Biological Station, 3700 E. Gull Lake Drive, Hickory Corners, MI 49060, USA