A DNA metabarcoding study of a polyphagous beetle dietary diversity: the utility of barcodes and sequencing...

Recently developed techniques of DNA barcoding and next-generation sequencing (NGS) overcome previous limitations of evaluation of animal diet composition and together are promising method in molecular ecology. The objective was to compare standard ABI Sanger sequencing with new high throughput sequencing (Illumina MiSeq) technique and the two selected plant barcodes (rbcL gene and trnL intron) in terms of the identification of host plant composition for the selected beetle species--the Centricnemus leucogrammus weevil. A comparison of two sequencing techniques showed that NGS (in this case Illumina) gave more exhaustive results than the Sanger method. Moreover, it was proven that a two-locus barcoding systems (rbcL and trnL) is sufficient for host plant identification from DNA isolated from insect bodies, at least at the genus level. A comparison of host plant composition among distant populations revealed that the studied species did not feed uniformly across its range. This probably reveals an ecological adaptation of geographically and genetically isolated populations. These findings, beside broadening basic knowledge on the use of barcoding and sequencing techniques for host plant identifications in insect populations, can have implications for conservation studies and strategies for rare and endangered species.