Population density of phytophagous insects in relation to vitality and area of hostplants (Lepidoptera: Momphidae, Diptera: Cecidomyiidae)
1988
Meyer, H. (Kiel Univ. (Germany, F.R.). Inst. fuer Zoologie) | Wrage, H.-A. | Irmler, U. | Heydemann, B.
Both, the dispersal of phytophagous insects and the anthropogenic impacts by mowing on plants and phytophagous insects had been examined within 25 square meter sized modell-ecosystems derived from biotopes of riverbank and hay meadow in Schleswig-Holstein. The weed Rorippa sylvestris (L.) Bess. and its phytophagous gall midge parasite Dasyneura sisymbrii (Schr.) showed no significant influence by mowing. A significant negative influence of mowing is demonstrated by investigations of Epilobium hirsutum L. and its phytophagous parasite Mompha epilobiella (Den. and Schiff.). Already a single mowing per year caused significant decreases of the number of plant stems, flowers (Mompha-microhabitats) plant size and of the number of apical shoot cocoons formed by Mompha epilobiella respectively. Investigations of different Agrostis stolonifera-stands showed a distinct correlation between the number of specimens of the phytophagous gall midge Mayetiola agrostivora Meyer and the cover of Agrostis stolonifera L. per square meter
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