Winter mortality of the bark beetle <i>Ips typographus</i> in standing trees and in the ground

Abstract Ips typographus is the most important tree‐killing bark beetle in Europe. In the north, it overwinters either in the bark of its host tree or in the ground, while in central Europe, overwintering in trees is most common. Few studies have estimated winter mortality of I. typographus in northern Europe. Mortality of I. typographus adults overwintering in killed trees was estimated by comparing densities per m 2 bark of live (one winter) and dead adults (five winters), and proportion of dead adults (one winter), in bark samples collected before and after winter in Sweden. Densities of live and dead larvae of predatory Medetera spp. (Dolichopodidae) were recorded in the bark samples (one winter), as was the amount of bark removed by woodpeckers from I. typographus ‐killed trees during winter foraging (five winters). Mortality of I. typographus adults overwintering in the ground was estimated by spring sampling of soil (three winters). The density of I. typographus live adults in trees was 3% lower after winter, while densities of dead adults was 6% higher and 5% lower respectively during two different outbreaks (differences after vs. before winters were non‐significant). The proportion of dead adults was 4% higher after winter (significant). Winter mortality of adults overwintering in the ground was on average 58%. The density of Medetera was 6% and 8% lower after winter for live and dead larvae, respectively (non‐significant). The amount of remaining bark on standing killed trees was on average 8% lower after than before winter (significant).