Insects inhabiting the trap-nests for Hymenoptera and effects of anthropogenic factors on them

The cavity-nesting solitary bees, wasps, and their natural enemies compose the community of insects inhabiting the trap-nests for Hymenoptera. This community, used in agriculture and biological control, is certified as a suitable bioindicator for measuring the condition and changes of ecosystems, landscapes, and habitats. The aim of this research is to establish the structure of the insect community inhabiting the trap-nests for Hymenoptera in Lithuania and to assess the effects of anthropogenic impact on it. Based on 377 collected samples from 117 sites of woodland habitats, 94 species of bees, wasps, and their natural enemies were determined along with 126 trophic links between them. After assessment of molecular, morphological and trophic differences of 1465 specimens of cleptoparasitic Chrysis ignita complex, independence of 15 sibling species was confirmed. Molecular markers, most suitable for differentiation of these cuckoo wasp species, are mtDNA ATP8, ATP6, CO3, and ND3 genes. Applying logistic binomial regression, general linear models and principal component analysis, the effect of all explored anthropogenic factors on the nesting probability and the brood abundance of trap-nesting Hymenoptera has been determined. One of these species, spider wasp Dipogon subintermedius, is the most suitable for bioindication of ecosystem naturalness by its relative abundance in trap-nests. The largest proportion of females and the heaviest prepupae of trap-nesting species have been detected in old forest stands, likely due to larger abundance of resources there or in neighbouring habitats