What makes a little hole in acorns ?

[Jason Green]

Originally Posted by rangersarah2

This may sound like a really stupid question, but I assure you that it is genuine. Why have you all thought weevil instead of gall wasp? What would the first sign of a gall wasp be?

A good question - one I thought of after posting. Well, wasps that use fruits as the developing area for the young use very fine egg tubes called ovipositors to 'inject' the larvae, whereas the weevil in question bores into it using the rostrum which I take to be bigger in diameter. As the hole and loss of contents is significant enough to make a notable difference to the weight of the nut, I thought something larger than a tiny wasp had to be involved. I also saw Lori's response which got me thinking.

As I said, it's a good question

[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?

[rangersarah2]

Also (you asked for this), why and how does the acorn get deformed?

[thunder]

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?

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

[Vincent86]

Agree with the people above me, it's the doing of an Acorn Weevil.

[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