[thedoc (OP)]

Luke Bizeray  asked the Naked Scientists:
   
With regards GM crops that resist insect pests:
 
I understand that insects and insect-like creatures are the bottom of the food chain and therefore very important.  Is there a danger that insect life will be threatened if we engineer fauna to resist them? How would the ecosystem cope if these "pests" were eradicated?
 
Luke
 
What do you think?

[CliffordK]

There is the eradication of certain species that potentially have had significant impact on the food chain.  For example, the Locust was eradicated in the USA in about 1877.  It was potentially a major food source for birds and other species.  Shortly after the extinction of the Locust, the Passenger Pigeon also went extinct (likely due to over hunting, but...  one wonders of the events are related).

As far as crop pests...  the impact of GM pest resistant plants may be less for a couple of reasons.  Many of the crops are non-native species.  Thus, the food chain wouldn't be dependent on them (although perhaps dependent on whatever they are displacing).  The mono-crop culture also tends to create pest explosions that may not be as common in nature.

Also, pest resistant crops may result in a decrease in the usage of pesticides, and thus fewer pesticides in the environment, and less killing of species that are not a significant problem for the plants.

[Don_1]

As Clifford wrote:

...... Many of the crops are non-native species.  .........The mono-crop culture also tends to create pest explosions that may not be as common in nature.......

The way I see it, we have created one problem which we are trying to fix with what may well turn out to be a bigger problem. GM could be a good thing, but it could be a Pandora's box. I think its effects on nature may only become apparent many years hence, by which time, it may be too late to put it in reverse. Small scale, short term testing in sealed environments will not reveal the whole picture.