Insect growth and development depend on nutritive value and secondary metabolite content of their host plants. This influence may be exerted through changing the activity of digestive enzymes which further affects efficiency of conversion of ingested food. This paper represents the results of investigation of feeding effects on the leaves of three oak species (Quercus cerris, Q. robur and Q. petraea) on growth, development and digestive enzyme activities of the 4th instar gypsy moth larvae (Lymantria dispar L.). Compared to larvae fed on Q. cerris and Q. robur leaves, larvae fed on Q. petrea exhibited the lowest body mass, midgut protein content and specific protease activity. Specific amylase activity was significantly reduced in the midguts of larvae fed on Q. robur while host plant did not affect larval duration upon molting into the 4th instar. Concomitant chemical analyses of leaves given to the 2nd and 4th instar larvae was carried out in order to explain the obtained results.
Analysis of defensive secretion of a milkweed bug Lygaeus equestris by 1D GC-MS and GC×GC-MS: sex differences and host-plant effect
