Does the odour of oak bewitch beetles?

How do oak bark-boring beetles (Agrilus biguttatus) decide where to feed and lay their eggs? Are they attracted by the smell of rotting trees? To try and answer this question researchers on the BAC-STOP project have been using odours given off by oak foliage and the bacteria that cause stem tissue rot in Acute Oak Decline (AOD).

The researchers are using a device called a ‘four arm olfactometer’ (pictured). Each arm presents different odours including a blank control. As this video below shows, the beetle is placed in the middle of the olfactometer and decides which arm to visit. The number of choices per arm the beetle makes are recorded and compared to find out whether a particular odour is preferred.

Insects like beetles often attracted to odours which help them find feeding and egg laying opportunities. Agrilus biguttatus, also known as oak jewel beetle or oak splendour beetle, is implicated in spreading the bacteria which cause Acute Oak Decline. A better understanding of beettle behaviour could help devise ways to reduce disease spread.