Second, synthetising a continually high level of defensive chemicals renders a cost to the plant.

This results suggest that there is a biosynthetic cost to constantly producing a high level of defensive chemicals.

Over the years there has been considerable research into these natural defensive chemicals with scientists seeking to add them to timbers from susceptible trees.

Studies have shown that younger trees produce defensive chemicals which deter infestation.

Some animals have adaptation to the defensive chemicals of jack-beans.

As undamaged leaves receive the signal, they begin producing defensive chemicals that make them difficult to digest.

Imidacloprid has been shown to turn off some genes that some rice varieties use to produce defensive chemicals.

The female needs the defensive chemicals to spread on her eggs as protection against predators.

They regurgitate on them, then drink the fluids to acquire these defensive chemicals.

The initial tests are intended to determine whether the vaccine is safe and capable of stimulating the body to produce defensive chemicals.