Flavonoid wing pigments increase attractiveness of female common blue (Polyommatus icarus) butterflies to mate-searching males

 Common blue butterflies (Polyommatus icarus) sequester flavonoids from their larval host plants and allocate these UV-absorbing pigments to the wings. In field experiments using dummies constructed from female butterflies, mate-searching males inspected flavonoid-rich dummies more intensively than those with little or no flavonoids. Flavonoid content as signalled by UV-wing pattern may indicate ontogenetically determined female quality or enhance detectability to males. Received: 21 March 2000 / Accepted in revised form: 17 May 2000     

Zur Freisetzung gentechnisch veränderter Mikroorganismen

Microorganisms have been being released into the environment for a long time, e.g., in agriculture or for biotechnological processes. Amongst these microorganisms were some that had been labeled genetically, or improved by selection. In recent years, efforts have been directed towards alteration or optimization of appropriate bacteria and viruses by methods of recombinant DNA technology. In some cases, first releases of such organisms have been undertaken in experimental plots. There is public concern about the environmental risks of such releases, and about possible adverse effects. The present status of research in this controversial field, the regulations available in Germany and the United States, as well as the prospects of such work for the future are presented.     

Thermisches Verhalten und hochauflösende Durchstrahlungselektronenmikroskopie von YBa2Cu3O7−x

Dr. Mertin haben wir für seine Hilfe bei der Interpretation der elektronenmikroskopischen Aufnahmen, der Deutschen Forschungsgemeinschaft und dem Fonds der Chemischen Industrie für ihre finanzielle Unterstützung zu danken.     

Direct measurement of negative pressure in artificial-biological systems

We are very grateful to A. Gessner for his great help in the construction of the apparatus and A. Meyer for performance of some pressure bomb experiments. This work was supported by grants of the Deutsche Forschungsgemeinschaft (Forschergruppe Ökophysiologie) to U.Z. and O.L.L.