What makes a little hole in acorns ?

[posie]

Thanks everyone for a fairly lengthy interesting thread,I think it could veer off course now to a more general theme . How about > CHANGES MADE TO FLORA OR FAUNA ETC BY THE ACTIONS OF INSECTS OR OTHER WILDLIFE , POSIE

[loripo]

Nice idea Start off a new thread - General Wildlife maybe?

[Blahah]

Originally Posted by rangersarah2

Thanks Jason. Would the first sign of the knopper gall wasp be the change in the acorn? How does the wasp that creates an oak apple make it's 'apple', and how does the one that creates a robin's pincushion make that one?

Originally Posted by thunder

It isn't the insect that lays the egg that 'makes' the galls, but the effect of the egg (possibly) and the developing larvae. I don't think anyone is sure quite how this happens, and why gall shapes are so varied, but presumably the larvae excrete a chemical that provides them with this protection.

henrya

There are several mechanisms by which galls are formed. Some are caused by the secretion of plant hormones at the time of egg laying, or in the salivary secretions of the developing larvae. Others are caused by mutualistic associations with bacteria or viruses. Some others are galls caused initially by a bacterial, viral or fungal infection and then later colonised by an insect laying its eggs within.

[posie]

What other examples are there of insects ( or other ) changing the appearance or damaging parts of plants , trees , etc ?

[Jason Green]

Originally Posted by Blahah

There are several mechanisms by which galls are formed. Some are caused by the secretion of plant hormones at the time of egg laying, or in the salivary secretions of the developing larvae. Others are caused by mutualistic associations with bacteria or viruses. Some others are galls caused initially by a bacterial, viral or fungal infection and then later colonised by an insect laying its eggs within.

Thanks Blah - and welcome to WAB

[posie]

Hi Blahah , likewise, Hello and Welcome

[Blahah]

Thanks for the welcome guys!

Originally Posted by posie

What other examples are there of insects ( or other ) changing the appearance or damaging parts of plants , trees , etc ?

There are several interesting galls which are caused by things other than insects. Nice examples which you might easily see in England include the Crown Gall - caused by Agrobacterium spp. These are the same genus of bacteria which have been harnessed in the invention of genetic engineering - they modify the host plant by transferring some of their DNA into the genome of the host plant, which then grows a perfect home in which the bacteria can thrive.

Another example is the gall left by mistetoe on oaks. Mistletoe is a parasitic plant - it gains most of its nutrition by penetrating the host tree with its roots and stealing nutrients. On oaks, a gall can develop around the site of penetration. Once the mistletoe plant dies, the gall can be left as a giant deformation on the tree - you can easily spot these on old oak trees. If you see a really old oak with a big round lump several feet across, this is a relic of a previous invasion by mistletoe.

A nice guide to some cool galls can be found here...
Plant Galls

Another way in which insects have modified plants is in the numerous examples of myrmecophily ("ant loving"). This is when a plant species and an ant species have evolved a symbiotic relationship in which each partner benefits (termed a 'mutualistic' association).

There are some really cool examples. I particularly like the swollen-thorn acacia species (Swollen Thorn Acacias) which develops giant hollow spikes. The ants live inside the spikes, using them as a fortress. If an animal tries to eat the tree, the ants attack it viciously. In return, the acacia grows tiny, nutritious, nectar covered buds which the ants collect as food.

Many carnivorous pitcher plants, a Nepenthes spp., have an association with ants which drink nectar from the pool in the bottom of its digestive chamber. In some associations, the ants help the plant by killing off mosquito larvae which like to grow in the fluid, but which prevent the plant from obtaining the nutrients it needs. In others, the ants attack predators which might disturb the plant. Sometimes they actually live within the chamber of the plant, and in other cases they visit periodically.

Read more here Co-operation Between Ants and Plants

-Blahah

[posie]

Wow ! We've got a tree with one part growing complelely differently to the rest of the tree. I can't do photos yet but will get help and post it and you may have an idea why it is like it. In the meantime I am learning a lot ! thanks everyone.

[rangersarah2]

This has become a great thread - thanks all. Keep it coming though. I've spent a few hours at work today researching gall wasps (if my boss is reading this - it was for work!), and understand a lot more about them because of you all.

[loripo]

Posie, what sort of tree is it? I believe some trees that have been grafted like fruit trees can do this.
Sarah, I spent about an hour looking up the way the wasps/moths use enzymes to commandeer(I'm sure that's not the technical word) the tissues of the plant host - mind you I wasn't at work

[solus]

Also, variegated trees can produce non-variegated branches which can make the whole tree look like it has two different sets of leaves: one green, one gold/variegated or whatever. There's a type of sycamore this happens with I believe, and it also occurs with some ornamental shrubs. A grafted tree (such as a fruit tree with one variety grafted on to a different rootstock) can sometimes produce shoots from the rootstock below the graft and these may be far more vigorous than the "new" tree. It happens, too, with my Corkscrew Hazel, where strong, straight shoots grow from below the graft and have to be regularly removed to prevent them taking over.

Whoops, we seem to have moved even further away from holey acorns and insects....

[posie]

Solus , I have this ridiculous vision of all our acorns having dear little glowing HALOS ,it was reading the last post , 'holey acorns' ..... we intentionally moved away from acorns anyway, onto ' changes caused' .

[BloomingMarvellous]

leftfield... Leftfield...LeftField...

[solus]

Originally Posted by posie

Solus , I have this ridiculous vision of all our acorns having dear little glowing HALOS ,it was reading the last post , 'holey acorns' ..... we intentionally moved away from acorns anyway, onto ' changes caused' .

No!!! Not "holy" but "holey" - as in having holes, not haloes!

[posie]

Oh Right OK. Sorry.

[posie]

Hello BloomingMarvellous, Would you please translate your last post on this thread ,and would you please also state to which post it refers, as I do not know what it means, and I would like to know, Thankyou, I'm learning all the time ! ! POSIE ..

[posie]

LORIPO ....I don't know what tree it is . I'll find out, I'll also have a good look at it in the morning so I can describe it's unusual-ness.

[BloomingMarvellous]

I'm sorry Posie, not sure how that happened. Wrong thread, should have put it on the Music thread.

[posie]

Originally Posted by solus

Also, variegated trees can produce non-variegated branches which can make the whole tree look like it has two different sets of leaves: one green, one gold/variegated or whatever. There's a type of sycamore this happens with I believe, and it also occurs with some ornamental shrubs. A grafted tree (such as a fruit tree with one variety grafted on to a different rootstock) can sometimes produce shoots from the rootstock below the graft and these may be far more vigorous than the "new" tree. It happens, too, with my Corkscrew Hazel, where strong, straight shoots grow from below the graft and have to be regularly removed to prevent them taking over.

Whoops, we seem to have moved even further away from holey acorns and insects....

well, thankyou for replying BM.

[BloomingMarvellous]

Your Welcome Posie.

[posie]

The fallen acorns that have not been attacked by the weevils are sprouting, is this normal at this time of year, I was wondering if the frost will kill the shoots. I've brought a few in out of the (future) frosts and put them in compost,leafmould earth mixture in a cool light barn,but sheltered from frost. If they survive I will pot them up til the Spring then set them outdoors. I love little baby trees, I've got some little hornbeams and hawthorns that started last spring.