Odour signals relevant to beetles in deadwood habitats : odorants olfaction and behaviour The overall objective of this work was to evaluate and determine volatile chemical cues (infochemicals) that determine insect wood interactions. The deadwood habitat comprises species that reproduce and spend obligatory most of their lifespan in any kind of wood and in any kind of decay stage including fungi that depend on wood. A gas chromatograph with mass spectrometric electroantennographic detection (GC MS EAD) has been introduced to define sources of volatiles and identify infochemicals in particular host produced kairomones but also allomones and pheromones relevant to selected beetle species of an either xylophagous mycophagous or xylomycetophagous feeding type respectively. Complex chemical profiles of wood deadwood and fungal samples have been analysed. Half of thirty compounds identified in the headspace of dry pine timber the most artificial kind of deadwood elicited responses in antennae of the Old House Borer Hylotrupes bajulus a major pest of structural softwood. Aliphatic aldehydes which are however not specific to the host tree species are proposed as potential infochemicals and complement the number of terpenoid host kairomones previously known for this xylophagous species. Experiments with felled beech trunks demonstrated that volatile chemistry changes over time and that decay over the length of trunks is quite variable. Potential host kairomones such as branched alcohols aldehydes and phenolics have been determined for the fungus farming ambrosia beetle Trypodendron domesticum. They provide a good basis for applications in integrated pest management and risk assessment of this secondary scolytine bark beetle. It attacks occasionally apparently healthy trees and is indicative for a recent emergence of pathogenicity in insect fungus symbioses ...