Weevil-plant associations revealed by multi-locus plant DNA barcoding

More than 50% species on earth are represented by plants and their associated insect herbivores. Understanding the dynamics of insect-plant interactions is a fundamental topic in ecology and evolution. However, it is particularly challenging to collect host plant data for a large group of phytophagous insects. Thanks to recent innovations in sequencing/analytical techniques, identification of host plants is now permitted by extracting and sequencing plant DNA from insect digestive tract. The current study sampled >50 weevil species (Coleoptera: Curculionidae) from Cuba, Panama, Nicaragua, Colombia and Venezuela. Three plant DNA barcode genes, rbcl, trnL and matK, were amplified and sequenced based on plant genomic extracts obtained from weevil gut. A large diversity of host plants was identified, amounting to ~20 families. At least 30% of the weevils sampled had fed on multiple plant species, sometimes across different families. A phylogentic codiversification analysis comparing the weevils and their associated plants was also performed and the results were discussed in light of the insect-plant coevolution theory.