In Central Europe, Melasoma 20-punctata is obligatory univoltine. Adults enter diapause beginning in July. In the region investigated, this leaf beetle feeds and oviposits on 4 different ...Salix-species: S. fragilis, S. alba, S. viminalis and S. caprea. All these willows enable development to the adult stage. Larval development was the same on all host plants at the same time of the season, however, weight gain during the larval and during the pre-diapause feeding periods of the adults was influenced by the N-concentration of the host plants. Furthermore, mortality rates during larval development and to an even greater extent more pronounced during the prediapause feeding period and following aestivo-hibernation were different on the various host plants. Feeding on foliage of S. fragilis resulted in the highest survival rates. Adults became adapted to declining food quality and compensated sublethal plant defence by more per capita damage on plants. Further experimental evidence shows S. fragilis to be the primary host plant. The efficiency of conversion of ingested food to body substance was always highest when feeding on foliage of S. viminalis. Survival rate during hibernation, however, never reached the level achieved when S. fragilis foliage was consumed. S. viminalis seems to be suitable for maintaining M. 20-punctata populations. By feeding on foliage of S. alba and S. caprea, mortality of adults during hibernation was extremely high. Populations feeding on these willows cannot persist for successive years. Nevertheless, in the field most individuals were found on S. alba trees. Discrepancies between observed distribution pattern and developmental success according to host plants are discussed
Energy cropping on derelict and waste land Dennington, V.N; Chadwick, M.J; Chase, D.S. (Derelict Land Reclam. Res. Unit, Univ. York, YO1 5DD (UK))
Journal of Environmental Management (UK),
(1983), Letnik:
16, Številka:
3
Publication
