ABSTRACT
Diverse external and internal stimuli mediate insect behaviour with chemically mediated behaviour, playing an important role in insect-plant interactions. This particularly occurs in phytophagous insects, which prefer specific host plants for feeding and oviposition and necessarily involve a physiological basis of induction thereby invariably involving changes in the thresholds of chemoreception to chemicals. The diversity of behaviour modifying chemicals relates to the types of behaviour, which may involve locomotor stimulants or arrestants causing a kinetic reaction in an insect or may attract or repel an insect thus causing an insect to orient itself towards the source or away from the source, respectively. Thus such phytochemicals could be feeding, mating or ovipositional stimulants or feeding, mating or ovipositional deterrents.
