Will Scots pine be the next victim of the Eurasian spruce bark beetle?

The Eurasian spruce bark beetle Ips typographus is a serious pest of Norway spruce.

Alarmingly, attacks also on Scots pine have recently become more frequent when beetle populations have been high and summers hot and dry, which reduces tree defenses.

We aim to understand why this beetle sometimes attacks pine and whether it is becoming a growing threat to these trees as a result of climate change.1) We will investigate the beetles’ host preferences for pine vs. spruce, which tree odors are involved, if a beetle odorant receptor for a ‘pine odor’ is important, and whether variation in beetle host preferences can be linked to genetic variation.2) Using pine as host may have fitness consequences for the beetles.

Thus, we will study reproductive success and several aspects of performance of both the beetles and their fungal symbionts (which contribute to beetle survival and development) on this host.

We will also test how well the nutritional profile of pine bark supports the survival and growth of beetles and fungi, and the beetles’ ability to produce pheromone from this host, which is needed to attract high numbers of beetles to kill the tree.The project will provide novel insight into the host specificity of I. typographus and an important ‘risk assessment’.

It may also contribute to improved management by identifying aversive odors that can be used to protect conifers from attack, and tree resistance markers which could be targeted in plant breeding programs.