A couple of months ago we heard a ticking noise in our living room and on further investigation we discovered it was coming from some hazel logs near the wood burning stove. Not a bomb, but beetle larvae. But which species?

We saved the logs from fiery destruction and put them out in Vanna’s studio. We didn’t have enough plastic boxes, so we left one of the logs in contact with a wooden table. When we lifted it up a couple of weeks later, we discovered that the occupant had taken some bites out of the table top, before burrowing back into its log.

Vanna kept checking the logs (now all safely within plastic boxes) and yesterday morning the adult beetles emerged: Tanbark Borer beetles (Phymatodes testaceus).

A couple started mating straightaway, so we left them in their containers overnight. This morning I released them, with their logs, onto a log “habitat pile” in a quiet corner of the garden. In total I counted 23 beetles. Previously, one or two have emerged at a time in the living room, but this was a record number, and a lovely surprise!

Tanbark Borers vary in colour from red to a deep blue black, as demonstrated in the photo below.

In southern European latitudes Tanbark Borers develop from egg to adult within a year but further north this can take three years. 

I cut the hazel logs myself in December 2018 and they would have been outdoors in our wood store until I brought them indoors at the start of this year, which suggests that our beetles developed from eggs laid last spring.