Response of walking spruce bark beetles Ips typographus to host odours

Abstract

A two-choice walking bioassay olfactometer was used to asses the response of walking Ips typographus (L.) towards the odours from logs of Norway spruce (Picea abies [L.] Karst.) subjected to various treatments. The odour coming from fresh log from standing, unstressed trunk was unattractive or slightly repellent to males over clean air in bioassay. The same odour was neutral or slightly attractive to females. Storing of a log for one month led to increased attractiveness to both sexes. The odour from log after bark beetle breeding was slightly more attractive to both sexes over clean air, excepting very low level of source contact in males. Results on overall attraction are more unclear for females. The level of source contact was the main difference between the males and females. The females manifested higher levels of source contact than males.