| Abstract: | Trophic niche partitioning among five most common herbivore species was described in respect to the stiffness of the leaves consumed on two trees of pubescent oak. Using discelectrophoresis procedure, genotypes at nonspecific protein loci were detected in two herbivore species, Tortrix viridana (Lepidoptera, Tortricidae) (Pt-2 locus) and Neuroterus quercusbaccarum (Hymenoptera; Cynipidae) (Pt-1 locus). Each locus was represented in studied samples by two alleles, F and S. Significant intra-species partitioning occurred among corresponding genotype classes in these two species. The mean niche overlap measured by Czechanowski index was the lowest (0.324 +/- 0.046) between genotype classes from different species. The intermediate values of this index (0.420 +/- 0.029) characterize niche overlap between genotype classes of given species and other species The highest values correspond to niche overlap between different species (0.578 +/- 0.049) or between genotype classes in the same species (0.585 +/- 0.078). The distribution of gypsy moth (Lymantria dispar) specimens along the leaf stiffness gradient significantly differed from that of T. viridana (FS-genotype class) and coincided with distribution of two other genotypes of the same species. The distribution of T. viridana (SS-genotype class) along the leaf stiffness gradient significantly differed from analogous distribution of heterozygote FS-genotype class of N. quercusbaccarum but was similar with distribution of homozygote FF and SS of the same species. These results means that different genotype classes in the same species interact differently with other species and even with different genotype classes of other species in the micro-community. Different genotypes of one species show different response to leaf stiffness and therefore unequally interact with each other as well as with different species. |
