Molecular Diet Analysis of Leaf-Grazing Katydids Based on DNA Barcoding

The diversity of herbivorous insects is associated with host plant diversity. The determination of dietary profile is a central topic in insect ecology. DNA barcoding, that is, taxon identification using a standardized DNA region, have been important to the recent advances in food web understandings. In this study, three commonly plant barcoding loci (i.e., rbcL, matK, and trnH-psbA) were chosen for screening of ingested plant DNA in 207 specimens of 18 leaf-grazing katydid species representing 4 subfamilies in China. The obtained sequences were queried against the Barcode of Life Database (BOLD) and GenBank for taxa identification. The results of identification were as follow: 3 Conocephalinae species consumed 10 plant families, with preference for Poaceae; 1 Mecopodinae species consumed 18 plant families, with preference for Fabaceae and Vitaceae; 11 Phaneropterinae species consumed 43 plant families, with preference for Juglandaceae; 3 species Pseudophyllinae species consumed 9 plant families, with preference for Balsaminaceae. Among these, only 81 out of 207 samples were identified at the species level when compares with NCBI and BOLD database. Our study added a significant amount of dietary information for leaf-grazing katydids in China. It is crucial to fully understand coevolution of katydids and plant, katydids diet resource requirements, and best practices for habitat conservation.