Size-dependent behavioral and antennal responses to doses of (+)-isopinocamphone and 1,8-cineole mixed with pheromone: a potential host selection strategy in female Ips typographus L

Key message 

This study revealed differing behavioral and antennal responses between large and small female Ips typographus to two bioactive oxygenated monoterpenoids, ( +)-isopinocamphone and 1,8-cineole, which serve contrasting ecological roles as aggregation pheromone synergist and inhibitor. Larger females were more attracted to ( +)-isopinocamphone and had larger antennal clubs leading to enhanced antennal sensitivity, potentially improving their ability to select suitable host trees. In contrast, smaller females were less repelled by 1,8-cineole but had higher antennal sensitivity despite smaller antennae. This discrepancy can be explained by behavioral decisions made after downstream olfactory signal processing in the central nervous system (CNS) and by the co-localization of 1,8-cineole with pheromone-sensitive neurons. Ecologically, small females may avoid competition with larger females by selecting less suitable trees. In conclusion, females’ body size influences olfactory-driven responseto potential host selection decisive volatiles, which can impact reproductive success and bark beetle population dynamics.

Keywords
Bark beetle; Olfaction; Pheromone; Oxygenated spruce monoterpenoids; Phenotypic variation; Host choice

Publication 
Moliterno, A.A.C., Shewale, M.K., Basile, S. et al. Size-dependent behavioral and antennal responses to doses of (+)-isopinocamphone and 1,8-cineole mixed with pheromone: a potential host selection strategy in female Ips typographus L. Annals of Forest Science 82, 34 (2025). https://doi.org/10.1186/s13595-025-01297-4

Data availability
The data is available in the Dryad Digital Repository: https://doi.org/10.5061/dryad.rxwdbrvn1.

Handling editor
Aurelien Sallé