Diversity of species and the occurrence and development of a specialized pest population - a review article.
The trophic interactions between plants and herbivorous insects are considered to be one of the primary relationships in the occurrence and development of specialized pest populations. Starting from the role of multicropping and the types of mixtures through the ecological benefits of intercropped plants, we explain the ecological conditions that contribute to the occurrence of pest populations. The dynamics of pest populations in crop occur in stages with the survival and development of pest in source of origin, invasion and distribution in crops, development and survival of the population, emigration to the another crop and (or) change of habitat. Possible effects of each stages are described based on the camouflage of visual effects, olfactory effects and reversal of feeding preferences. Fundamental theories of natural enemies and concentration of food resources have been explained to refer to the empirical data.