Galls

[goosey]

I have only just become familiar with Galls and what they actually are. I thought I would try and explain these photographs instead of just saying “these are Galls” I think this is right, I am sure someone will correct me if it isn’t!

The large growths on the undersides of these oak leaves are Cherry Galls. They are made by the Cynips quercusfolii wasps (Cynipidae family) and each gall contains a grub, a parthenogenetic female (they produce offspring without mating). They will emerge in midwinter as a gall wasps. Then will lay their own eggs on or close to an Oak tree trunk in the Spring, which become tiny purple “sexual generation” (male + female) galls which mate to produce these large cherry galls again – full circle!

In the second photo , there are some small growths on the same leaf as the cherry gall, these are Spangle Galls, made by Neuroterus quercusbaccarum, another Gall wasp. In spring wasps barely 3mm long will hatch from these, they will all be parthenogenetic females. They will then lay their own eggs in oak male catkins (flowers), when they hatch the plant tissue will swell around larvae, this is what the larvae feed on, as the larvae grow so does the gall around it. Male and female wasps emerge from these, they will mate, lay eggs on the leave and the whole process starts again.


There all lots of types of oak gall as well as galls on other plants like roses, willow and brambles, which I am yet to see myself – or probably have seen but not realised what they were. I think it would be good to see more images here of different types – so if anyone has any……………. I’d love to know what to look out for in future.

[Suzanne B]

Hi Goosey
That's really interesting info.
I've seen pictures of Galls before but never realised what they were, so your explanation is really helpful.
I will look out for them in future and see if I can get some photos to add to your collection.

[goosey]

Thanks Suzanne, I have seen pictures of galls on roses and they are so attractive fluffy, nicely coloured and look like flowers in their own right. I haven't seen any in the wild though. Some of the others I saw when I was looking for info on the images I posted, were quite ugly. I hope you do find some different ones to post. The were hundreds of the little spangle gall type around but and only a few of the Cherry ones and I didn't spot anything different.

[paul m]

Fascinating things. This has, in my part of the world, been a particularly good year for the nest-like ones such as the robin's pin-cushion seen on roses and caused by Diplolepsis rosae Galls Page 1
This one was as big as my head but seemed to be on a willow:



But there's some rose hips in there. I couldn't look more closely because it was overhanging the canal!

[goosey]

That is certainly a size! I never imagined Galls could ever get to that sort of size.
Thanks for that great link, it will come in handy when I find some more .

[paul m]

Originally Posted by goosey

That is certainly a size! I never imagined Galls could ever get to that sort of size.
Thanks for that great link, it will come in handy when I find some more .

There's a British Plant Gall Society which has set up a website and hopes to have a comprehensive gallery but it's far from that at present.

There's a technique for showing the animals within some galls - take (e.g. a lime leaf with those protruding galls, put it into caustic potash (or caustic soda) and the leaf becomes transparent ... fascinating well, I thought so ....

[goosey]

It does sound fascinating a bit like an x-ray. Does the caustic potash only effect the lime leaf so it does't harm the larvae? It's amazing how people come up with these ideas in the first place.
I had alook at the British Plant Gall Society web pages - it looks as if it will be a useful resource in the future. A huge amount of work, time and money has to go into these things even when they have all the info' already. It will be well worth it in the end I am sure.

[H Dogg]

Yes Gall's and Cynipidae are very interesting, although not only caused by hymenoptera also mites, aphids, psyllids, gall midges and fungi cause gall's.

Chalcids such as Torymus sp are interesting too as their parasitic larva feed on the Cynipidae larva within the gall and then finish off the gall.

[goosey]

Originally Posted by H Dogg

Yes Gall's and Cynipidae are very interesting, although not only caused by hymenoptera also mites, aphids, psyllids, gall midges and fungi cause gall's.

Chalcids such as Torymus sp are interesting too as their parasitic larva feed on the Cynipidae larva within the gall and then finish off the gall.

Do you have any photos you can add to the thread to show us please?

[H Dogg]

Originally Posted by goosey

Do you have any photos you can add to the thread to show us please?

I need to buy a macro lense for the Chalcids. As for the gall's afraid ive only really got into the photographic side fairly recently. More of a biology first photo second man. I will have a scout round see what i can find. the only photo's i do have are from Diplolepis rosae and a very blurry Biorhiza pallida oak apple gall (very common).