The effect of mating on female sexual behavior of Teleogryllus commodus Walker

Summary Virgin Teleogryllus commodus females show rhythmic locomotor activity in light-dark (LD) and constant light (LL) conditions. A taped 3-h calling song stimulates them into further walking, and they lay few eggs. Successful mating suppresses or reduces circadian-controlled walking, but in LL-conditions the free-run still persists. Mated females no longer respond to the 3-h calling song. The number of eggs laid within 24–72 h after insemination increases, and the three effects of mating occur independently of one another. The possible physiological basis of these changes and their ecological and behavioral significance under field conditions are discussed.     

Long-term sampling method for polychlorinated dibenzofurans (PCDFs) and dibenzo(p)dioxins (PCDDs) in flue gas of combustion facilities

A long-term sampling method for PCDF/D in emissions from combustion facilities is presented. The sampling of PCDF/D was performed over a four week period. The results are compared to results of four one-week measurements.     

Biotoxizitätstests mit PAK

There is great need for toxicity tests with higher plants for the investigation and monitoring of chemicals in the environment — especially for tests which are quick, easy, and inexpensive. Such tests should add to and improve current guidelines, e.g., OECD- and BBA-Guidelines. This article describes the nodulation of leguminous plants withRhizobium bacteria used in a bioassay with polycyclic aromatic hydrocarbons (PAH). Plants growing on a solid medium were exposed simultaneously to bacteria and PAH. This axenic culture system allows to observe the impact of PAH on plant growth and the interaction between plant and bacteria (nodulation). Dose-response-experiments indicated that nodulation measured as number of nodules per plant, was more sensitive to the inhibition by PAH than other plant growth parameters.     

Economists' opinions on environmental policy instruments: Analysis of a survey

Incentive instruments (effluent charges) are theoretically expected to be preferred to direct regulations (individual emission ceilings) by university-employed, theoretically inclined politically right-wing, professional economists living in a market-oriented country, ceteris paribus. Public sector employed, politically left-wing, professional economists living in a country with a long tradition of government involvement prefer the regulatory approach, ceteris paribus. These theoretical hypotheses tend to be supported by a bivariate probit analysis based on a survey of more than 1400 economists in five countries.