Combining the power of DNA and morphology to stop biological invasion in wood-packaging material

Damage from invasive insect has cost the U.S. economy billions of dollars. Pests including non-native longhorned beetles (Cerambycidae) and jewel beetles (Buprestidae) frequently arrive at ports of entry as larvae in wood packing material (WPM) used for international shipments. Highly conserved larval morphology makes these invasive insect difficult to identify below family level. Valuable regulatory and risk assessment information is lost when larvae remain unidentified. To overcome the challenge, we applied DNA barcoding in conjunction with rearing larvae to adults to identify wood-boring insect associated with WPM. From 2012 to 2015, a total of 338 cerambycids and 38 buprestids were intercepted at six U.S. ports, among which 265 specimens were identified to species or genus based on their DNA barcodes. Ninety-three larvae were successfully reared to adult beetles for morphological identification. Morphological identification confirmed 14 new DNA barcodes for 10 species that have not been included in public databases. Together, the two methods identified 274 cerambycids (belonging to 23 genera) and 16 buprestids (belonging to 4 genera), of which more than half are categorized as reportable quarantine pests. We showed that highly destructive forest pests such as Asian longhorned beetles and velvet longhorned beetles frequently enter the U.S. in WPM, highlighting the need for improvements in phytosanitary treatment efficacy. Linking pest species and cargo destination suggests repeated introduction through the same pathway. With some caveats, DNA barcoding proves to be an effective tool in rapid identification of larval insect for regulatory science.