What type of wood eating insect is ...

[Deimos]

What type of wood eating insect is “blue and silver” (?),

makes large holes in wood (>5mm diam) makes a buzzing sound and is only

flying around spring summer.  Tends to

only attack softwood.  I’m told its not

a great threat to me (as most of my roof timbers are oak)

Any thoughts ?

Ian

[chris pp]

Sounds like the Blue Carpenter Bee, Xylocopa violacea, Abeille Charpentiére, it is one of the solitary bees found in southern and central Europe. It is 2 to 3 cm long, glossy black all over with sparse black hairs, opaque wings which are dark brown with a lilac-coloured sheen.

Reproduction takes place in May / June with adults that have over wintered from the previous year. They will often be seen going in and out of holes looking for suitable wood in which to make their egg chambers.  If this is in the gaps in the walls of your stone house you should not be concerned as it does not like dry, hard wood. Degraded old logs, soft wood, dead trees and branches etc. being the preferred location. It will in fact look in any hole, even those in concrete posts, I think it must just see a "hole" and investigate.  There is only one entrance hole which then opens into a number of chambers where eggs are laid one at a time, each one has a pollen peelet placed between it and the next as starter food!!

Photo.   http://www.planetepassion.com/carpenterbee.jpg 

Chris

 

[Deimos]

I'll measure the holes tomorrow but I thought they were a

bit small for Carpenter Bees.  I have some trees in the fields where bark

damage has exposed the tree “core” and have Carpenter bee holes in those and

they are certainly quite a bit larger than the ones in the rafters.

The holes are actually in the rafters.  Roofer guy (who did a "must

be seen to be believed" impression of the insect) said they were not a

serious threat to me as most of the roof is Oak and they will only get into the

sapwood (rather than the heartwood bit) and thus not get in enough to cause

structural problems.  I’ve printed out

your picture and will ask him again when he returns with the devis.

It all started when I was closing up all the loft/barn doors

for Christmas away and saw loads of the “worm shaving” on an attic floor.  Looked up and saw the ridge beam broken and

looking in a bad state to got the roofer round.  He then reckoned that the ridge was fine and set about searching

for the source of the “savings”.  Ay (or

may not) have been the cause but he spotted the larger holes and decided that

in the absence of other things it may be these.  In practice it may be a bit of worm in the main beams – but as

they are Oak and around 1 foot sq in section, the bulk of them is heartwood and

they are totally solid with maybe a bit is worm in a couple of placed limited

to the surface.  Might give it all a

couple of sprays just in case.

Ian

[chris pp]

I would suspect that your larger holes have been there since the early years after installation, oak and chestnut are rarely touched once well seasoned as long as they remain dry, even woodworm like an easy life. I can't think of anything else that matches the "colour and sound" of your bug that tunnels in dry timber.

Try to get your roofer to write the name down, even if he only gets it spelt badly it should be possible to figure out what it is.

Chris

[Owens88]

capricorn?

[Deimos]

I asked about "capricorn" without knowing if the French name for the beetle was the same and he said no - I guess either because the name is different and thus he did not know what I meant or maybe it was a different "bug".

Ian

[chris pp]

It could be Capricorn but it doesn't really fit the description on colour. In French it is called Capricorne des maisons (Hylotrupes bajulus). So, no big difference in the name.

Chris

 

[Deimos]

Measured the holes and I reckon they are big enough for

carpenter bees (approx 1cm across). 

However, I could only find 2 (sure the roofer found more) and I’m sure

they do not explain the shavings on the floor. 

However, I guess I not worried as there is a little surface worm on some

of the beans (where there is some sapwood left on the oak.  Roofer guy went round jabbing his knife

around the place and said there was no problem so I may treat, particularly as

I do have another attic to treat as well.

I will double check when (if) he comes back about the

carpenter bees.  Its definitely in Oak rafters

, though probably sap wood.  I assume

they would not use an old knot as I would think there would be some

particularly hard wood surrounding the knot ?

 

Ian