Colonisation potential of the bark beetle (Taphrorychus bicolor) on beech logs and logging residues: ecological...

The bark beetle Taphrorychus bicolor has been traditionally classified as a secondary pest of European beech. However, climate-induced stress and increased host availability may enhance its importance in forest ecosystems. Despite the high abundance of this pest, data on its reproductive biology and colonisation preferences remain limited. Therefore, we conducted three experiments, each addressing a different aspect of T. bicolor ecology (colonisation density, population-substrate relationships, and reproductive success), to assess its colonisation behaviour on beech logs and logging residues at selected Central European sites.

In the first experiment, both trap catches and entry hole densities declined between years, but no significant relationship between trap catches and colonisation density was detected after accounting for year effects. In the second experiment, reproductive success was quantified by comparing the numbers of entry and exit holes and emerged adults from colonised logging residues. Exit holes were moderately correlated with beetle emergence, whereas entry holes showed weaker predictive power. This pattern may reflect mortality or re-entry behaviour. In the third experiment, T. bicolor was the dominant coloniser across five study sites, whereas ambrosia beetles were sporadic, suggesting limited interspecific competition under the conditions studied. Colonisation density was significantly reduced under full sun exposure but unaffected by pheromone- and kairomone-based lures or log dimensions.

T. bicolor showed consistent reproductive success on small-diameter beech logging residues with limited interspecific competition. Exit holes provide a reliable proxy for emergence, supporting logging residue management. © 2026 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.