Behaviourally activity of Ips typographus (L), (Coleoptera; Scolytinae) semiochemicals, selection of new candidates as a green alternative of bark beetle management

Antonioni Moliterno, MSc

Disertační práce

Abstract:

The European spruce bark beetle, Ips typographus, is one of the most destructive forest pests of Norway spruce, Picea abies, in Europe. Its increasing impact under climate change highlights the need for improved methods for early infestation detection and environmentally sustainable management. This dissertation investigated the chemical ecology of the P. abies - I. typographus interaction by examining three connected processes: the spatial distribution of host volatiles around recently infested trees, the effects of selected host-associated compounds on pheromone-mediated attraction, and the influence of female phenotype on behavioural and antennal responses. The first study evaluated the three-dimensional distribution of α-pinene emitted by recently infested Norway spruce. Volatile organic compounds were collected under laboratory and field conditions using solid-phase microextraction fibers and HayeSep-Q® sorbent cartridges. Field sampling was conducted at different distances, heights, and cardinal directions around infested trees. α-pinene was detectable around recently attacked trees, but its abundance varied spatially and between field trials. Abundance was generally recorded close to the stem, although the distribution was strongly influenced by sampling position and environmental conditions. These findings demonstrate the potential of host volatiles for early infestation detection while emphasizing the dynamic nature of volatile plumes in forest environments. The second study examined the effects of eight synthetic host-associated compounds combined with the aggregation pheromone of I. typographus. Field trapping experiments showed that 1,8-cineole reduced beetle attraction at all tested release rates, while estragole produced an antiattractant effect at the highest release rate. In contrast, (+)-isopinocamphone enhanced pheromone-mediated attraction. The remaining tested compounds did not significantly alter trap catches under the experimental conditions. Natural enemies, including pteromalid parasitoids and staphylinid beetles, were also captured, although their responses varied between locations and treatments. The third study investigated whether female body size and antennal morphology were associated with differences in behavioural and electrophysiological responses. Field traps containing high release rates of (+)-isopinocamphone captured larger females, whereas 1,8-cineole was associated with smaller females under some conditions. Large females had larger antennal clubs and showed stronger electroantennographic responses to high doses of (+)-isopinocamphone. In contrast, small females responded more strongly to several doses of 1,8-cineole. Responses to the aggregation pheromone did not differ significantly between female size classes. Overall, this dissertation demonstrates that host selection by I. typographus is shaped by interactions among volatile production and dispersal, compound identity and concentration, pheromone communication, environmental conditions, and beetle phenotype. The findings support the use of αpinene and related volatiles in early-detection systems, 1,8-cineole and estragole as potential anti-attractants, and (+)-isopinocamphone a possible pheromone synergist. These results provide a foundation for more selective, semiochemical-based approaches to bark beetle monitoring and management and may help reduce reliance on conventional insecticides in European spruce forests.

Keywords

infestation, protection, synergistic, host selection, antagonist, α-pinene, bark beetle, electroantennography, field test, forest

Jazyk práce: angličtina

Datum vytvoření / odevzdání či podání práce: 17. 8. 2026

Obhajoba závěrečné práce

• Vedoucí: doc. Ing. Anna Jirošová, Ph.D.

Česká zemědělská univerzita v Praze

Fakulta lesnická a dřevařská

Doktorský studijní program:
Global Change Forestry