Raising galls privately?

[Jason Green]

Hi all,

I came across an Oak Leaf with a fair few Oak Spangle galls on the leaf's underside. What's more, it seems the cynipid wasp Neuroterus quercusbaccarum is well-known enough online. If I was to take a leaf with some of these attached, could I monitor it at home? If so, how should it be kept, when will the adults emerge, etc.?

Thanks for reading!

Take care,

Jason

[Deer Stalker]

Hi Jason,

hedgerow had blog where he/she was rearing wasps from galls. Hasn't been online since January though....

Wild About Britain - hedgerow

[Jason Green]

Ah, thanks Simon. I'll look into it

[Acutipuerilis]

Here's his website:
Parasitica - parasitic wasps
It's potentially a vast piece of work, and already he's got a lot of interesting stuff on it.

The thing to consider is whether the gall-dwellers depend on the tree being alive... personally, I really don't know, but given they're feeding on the gall interior as it grows, it's quite possible.

[charlieb]

Try plucking a leaf and keeping it sealed in a bug pot - they'll stay green for months if your lucky (and maybe add a few drops of water to keep it moist)

[Jason Green]

Originally Posted by Acutipuerilis

The thing to consider is whether the gall-dwellers depend on the tree being alive... personally, I really don't know, but given they're feeding on the gall interior as it grows, it's quite possible.

Ah, a very good point. I suppose you could keep the leaf alive by inserting the stem into new, moist compost or even collecting the gall and leaf when the gall is more mature, or even taking the leaf over the winter period when the tree is growing less?

Bare in mind I don't know if they over-winter exactly, but since his WAB blog speaks of some emerging in January.

Thanks Charlie, a good point too - will do!

[Torymus]

Coming in rather late on this but - rearing the galls is easy. Remove the galls from the leaf and keep them in a small clear container with non air tight seal eg cloth or fine mesh (ladies tights!). You could try to keep the galls moist - in sand and spray with water occasionally and this would improve the chances of emergence but just about anything can work - except inside the house with the central heating on! Keep the container in an outside shed over winter and the insects will emerge in March. Continue to keep the galls in the same way and parasitoids of the gall causer may emerge later in May and June. To give yourself the very best chance of rearing the insects collect more galls as late as possible this year. I usually collect N. quercusbaccarum late October just before leaf fall - some galls will remain attached to the leaf even after leaf fall and you can try these too. Good luck.