Tomatine feeding deterrency

Leptlnotarsa decemllneata, -Tomatine also acts as a feeding deterrent for U deceml lneata (25) and the tomatine content of the wild tomato species that are resistant to L, deceml lneata Is generally higher than that of commercial tomato cultlvars (8). Nonetheless, the evidence that -tomatine Is responsible for the resistance of any tomato genotypes to 1 decemllneata Is Inconclusive, but suggestive. 

It should also be remembered that the defensive role of alkaloids in host protection is probably not as simple as the presence or absence of a single functional group on an alkaloid or even whether the alkaloid is in the host plant at all. In many cases, there may be additive effects of feeding deterrent compounds based on the entire chemical composition of the host plant. For example, when the alkaloids nicotine and tomatine, each of which have been shown to exhibit feeding deterrences of 25%, were fed in artificial diets to Locusta migratoria the overall feeding deterrence was approximately 50% (19). In this case the alkaloids acted in an additive fashion to produce a more effective chemical defensive mechanism. Adams and Bernays (19) went on to show that this additive characteristic of feeding deterrence was not restricted to alkaloids but was equally effective with alkaloids and various combinations of phenolics, terpenoids, and other miscellaneous secondary plant compounds. 

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