Insect-plant interrelationships

Abstract

The green plants and insects represent the two dominant groups of living organisms on Earth. The green plants occupy the most capacious segment among all biological organisms, whereas the insects are the most specious group. These two 'empires' are interconnected as well as interdependent. Green plants are the primary producers of food, and all animals being heterotrophs depend directly or indirectly on plant-produced food. In turn, nearly three fourths of all angiosperms require the services of insect pollinators. The entomophilic flowering plants and their insect pollinators thus represent the most evident and widely applicable example of mutualism among living organisms. But a wide variety of phytophagous insects also flourishes, diversifies and sustains on these plants. Consequently, the plants have evolved a dizzying array of morphological and biochemical (constitutive as well as induced) barriers for protection against insects and other herbivores. Evolutionary interactions between plants and insects may have contributed to the increased biodiversity and success of both these groups. The study of these interrelationships, as outlined in this chapter, is of great practical significance for the future agricultural production. The development of pest-resistant cultivars of crop plants and progress in integrated pest management both require an intricate understanding of insect-plant relationships State-of-the-art techniques such as mutant analysis, metabolomics, RNAi and proteomics developed during the last three decades have been instrumental in providing improved insight into these interrelationships.