Abstract:  The trophic relationship of herbivorous insects and host plants are complicated in agroecosystem. The common methods, such as direct field observation, morphological analysis of the gut content and stable isotope analysis, are difficult to fully analyze the trophic relationship. Recently, the rapid development of DNA-based technology, which uses a short DNA sequence to achieve the rapid identification of host plants fed by herbivorous insects, provides a new option for exploring this relationship. In this review, three DNA-based methods were comprehensively introduced, including diagnostic PCR, DNA sequencing and next generation sequencing (NGS). Diagnostic PCR, including single PCR and multiplex PCR, is applicable to analyze the trophic relationship between herbivorous insects and their known host plants. DNA sequencing can resolve the complete host data of target insects without a prior knowledge of host plant species. NGS can achieve the sequencing of mixed samples in a short time and improve the identification efficiency of host plants significantly owing to the massive expansion of the DNA database of insects and host plants. Diagnostic PCR and DNA sequencing have made significant research progress in studying the feeding behavior of soil-dwelling pests, the host breadth of herbivorous insects, the host selection and preference of herbivorous insects, etc. Taking the advantages and disadvantages together into consideration, the strategy of application of DNA-based technology in combination with stable isotope analysis or other methods is proposed to comprehensively analyze the trophic relationships between herbivorous insects and host plants in agroecosystem in future.

Key words: DNA-based technology, diagnostic PCR, DNA sequencing, next generation sequencing (NGS), herbivorous insects, host plants, trophic relationship