author(s)
K Siddhartha, C Chinniah and M Shanthi

abstract
Morphological and biochemical features of host plants have an impact on survival, feeding, distribution, reproduction and behavior of many phytophagous insects. Chemical communication is most common between the insects and their host plants. The survival and the behaviour of many of the phytophagous insects depends on their host plants. Sex and aggregation pheromones play a major role in their intra-specific communication among the insect species. The behaviour and physiology of insects including pheromonal communication optimizes the mating and reproduction is by the host plant phytochemicals. Host plants aids insects by producing cues to find mating partners, and insects have also developed some tactics to optimize mating for better reproduction using these host plant chemicals. In general, the phytophagous insect pests are a major constraint in the production of agricultural, horticultural crops and plantation too. As many broad-spectrum chemicals are restricted as a result of indiscriminate application, a need to develop better alternative control method with long term sustainability is the need of hour in the management system. Development of pheromone-based lures can be of greater importance in control along with the use of host plant chemicals to enhance or synergize sex attraction of insects. Knowledge on insect behaviour in response to the combinations of their host plant chemicals and their pheromonal communications is important in research and for production of sexual and host plant attractants as a new approach to biologically manage the phytophagous insect pests.