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Undetermined larva in a stem gall


Small white grubs were found in each elongated stem gall, usually half way along. The larvae is possibly the cause of the gall formation or possibly a secondary infection of another bug, long eaten.


Roadside Eucalyptus sapling


This dissection is additional to these spottings Further information is needed

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MartinL 7 years ago

Thanks for your interest asergio.
Clearly gall parasites employ various mechanisms to control their hosts. I consider galls might have played a part in plant and animal evolution, causing cheap genetic information for the development of new structures such as flowers or spikes when the genetics become integrated (as might occur more easily with viruses).

Sergio Monteiro
Sergio Monteiro 7 years ago

Thank you for the info, Martin. Since I started to watch things more closely (literally...), I noticed the incredible variety of galls. The most amazing, for me, is that the shape, color and surface of galls many times have nothing to do with the original plants. I mean, if they were just scars, they would keep the original surface, right? But some galls even have "hairs", where the host plant doesn't. I don't expect to become an expert on galls, but that is a really interesting subject for me. Please, keep me informed about your discoveries.

MartinL 7 years ago

Asergio. I can trust you to want some serious science.
I think this gall is produced by a soft bug (parasite) and the wasp/fly (parasitoid) was laid at a later date to eat the bug and live in his house.
I think the gall is grown by the egg/larva excreting growth hormones or chemical irritants to stimulate the extra tissue growth. The parasite must control the complex growth pattern rather than letting the host DNA doing it all. My points are not referenced and I'm still learning this stuff and struggling to find good info.

Mark Ridgway
Mark Ridgway 7 years ago

No other detritus in there? Looks clean. Beetle or fly larvae?

Sergio Monteiro
Sergio Monteiro 7 years ago

What fantastic galls, Martin. Very nice, indeed. There is one thing I'd like to know: how the larvae act to form the galls. Could it be that the larvae affects the plants DNA, like a virus does? Or the gall is just some scar tissue, that grows as a reaction to the larva's attack? Or, a last possibility, the larvae secret hormones that direct the growth of the plants tissue?

Spotted by

3138, Victoria, Australia

Spotted on Sep 20, 2012
Submitted on Sep 20, 2012

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