Tag Archives: Nut weevils

My over-the-road-oak June

IMG_2847As you can see, my oak hasn’t really changed since May, when it achieved its full canopy.

However, what’s new this month is that for the first time I saw a green woodpecker in the oak (you’ll have to trust me on this, it wasn’t captured on camera) and that, together with a comment from Bob Flowerdew on Gardeners’ Question Time regarding the number of species the oak supports, got me thinking about the oak as a habitat.

According to the Woodland Trust oaks support more life forms than any other native tree and host over 280 species of insect, who in turn supply many British birds with an important food source.

Last month I talked about the Oak Apple, caused by the Gall Wasps’ larvae.  Today I thought I’d look at a couple of other insects residing in the oak.

Firstly, the oak bark beetle (Scolytus intricatus), which depends on the oak tree for its survival. The female oak-bark beetle gnaws a vertical tunnel into the bark of the tree, forming a chamber where she deposits her eggs. The larvae develop in or under the bark and when they emerge, they gnaw tunnels of their own away from the original chamber, creating a vast network of tunnel homes. whose larvae create a distinctive pattern of galleries in the tree’s wood.

See photo from http://moremoth.blogspot.co.uk/2012/01/bark-beetle-galleries.html below showing the larger horizontal ‘mummy’ tunnel and all the larvae tunnels radiating from it. Note how their tunnels widen as they travel away from the centre.  Oh they grow up so fast!

Nut weevils, on the other hand, don’t use the tree itself, but instead use the acorns.  They have long, thin snouts (called a rostrum) and the female uses it to drill a hole into an acorn where she lays her eggs. When the larvae hatch they grow inside the nut until they are ready to pupate after the acorns have fallen to the ground.

See photo below from http://jenlynch.files.wordpress.com/2011/11/acorn-weevil-larvae.jpg.  Is it just me or does it look like a smile?

With thanks again to Lucy at Loose and Leafy for hosting this ‘Follow a tree’ meme.

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