1. Araneid spiders of genus Araniella are attacked by three polysphinctine parsitoid wasps Polysphincta boopsTschek, P. tuberose (Gravenhorst), and Sinarachna pallipes (Holmgren). In the present study, the trophic niche of sympatrically occurring parasitoids and the host manipulation they induced were studied. The aim was to identify whether the variation in host response to manipulation is as a result of differences among parasitoids or among host species.2. It was found that final instar larva forced the spider host to build a threedimensional (3D) 'cocoon web' to protect the parasitoid during pupation. The behaviour of parasitoid larva and the induced modification of the web architecture differed between wasps of genus Polysphincta and Sinarachna but not among three spider species. The larvae of genus Polysphincta forced the spider host to build the 'cocoon web' with a high thread density within which the pupa was positioned horizontally. The larvae of Sinarachna forced the spider host to build web with sparse threads and the pupa was positioned vertically in the middle of the 'cocoon web'.3. There seems to be an investment trade-off in parasitoid wasps: some species manipulate the host to build a dense protective web, while pupating in a sparse cocoon, whereas others make the spider produce a sparse web but build a dense pupa wall.

Physiological parameters are sensitive and provide information on the toxicity of herbicides in plants. The impact of herbicide application on plant transpiration was evaluated by the sap flow method during 2009–2011. The aim of this work was to verify the sap flow method for determining the effect of herbicides on the basis of continuous measurements of the transpiration flow. Helianthus annuus was used as a model plant species. The two different herbicides tested in this study differed by the effect of active ingredients bromoxynil and clopyralid. The water flow was measured using sap flow meter T4.2. The impact of herbicides was assessed by comparing measured transpiration rate (Q) after herbicide application with an extrapolation of transpiration rate of plants before herbicide treatment (Q_calc). After treatment with bromoxynil the Q values decreased significantly compared to Q_calc. For plants treated by clopyralid, the decline of actual transpiration (Q) compared with the modelled one (Q_calc) was less substantial and the plants continued to transpire after the treatment. The effect of herbicides was also verified using infrared gas analyser and chlorophyll fluorescence meter.