On Fri, 8 Aug 2003 06:18:46 +0100, Oz
posted:

Moosh:} writes
They fed resistant larvae of the diamondback moth - an increasingly
troublesome pest in the southern US and in the tropics - on normal
cabbage leaves and ones that had been treated with a Bt toxin. The larvae
eating the treated leaves grew much faster and bigger - with a 56 per
cent higher growth rate.

Can you quote any of this study? It costs to read it, I believe.

They found that the larvae "are able to digest and utilise" the toxin and
may be using it as a "supplementary food", adding that the presence of the
poison "could have modified the nutritional balance in plants" for them.

Along with all the other thousands of proteins the plant supplies

The devil is in the detail, I suspect.

I would be astonished if the amount of BT was enough to constitute a
supplementary feed. However I can see an easy mechanism to produce this
result, although whether this is true of this trial or not I cannot say.

Plants attacked by pests will elevate their toxin levels as a response.
If the untreated plants were under attack (or their neighbours were)
then they would increase their toxin level.

If the Bt plants perceived themselves in a pest-free environment then
toxin levels would be low, if the untreated perceived themselves is a
pest zone then they would elevate their toxin levels.

The toxin levels in plants are known to have strong effects on growth
rates of animals eating them.

Interesting thoughts, thanks.
I'm not rich enough to afford $19US for the dubious value of reading
the full article. If someone else has it, then please post here.

It amazed me that such a tiny amount of one protein could produce such
growth differences. Your explanation of growth inhibition from a
predated crop certainly fits.