Citizen Science and Environmental DNA Reveals Site of an Invasive Paropsisterna beata (Newman) (Coleoptera: Chrysomelidae) Population in New Zealand

Abstract

More than a decade after being declared eradicated, a population of the Australian blessed leaf beetle Paropsisterna beata (Coleoptera: Chrysomelidae) was located in New Zealand in 2026. The pest has been found and photographed three times by citizen scientists approximately 25 km north of the original Wellington infestation and reported on iNaturalist. An environmental DNA (eDNA) match from a water sample then directed searching to Eucalyptus trees visible on Google Earth upstream. This sequence of events leading to finding an established population highlights the potential for citizen science observations and eDNA monitoring to both uncover and pinpoint a cryptic pest's location as part of biosecurity surveillance.