Public reporting is essential for controlling the invasive yellow-legged hornet: a novel model simulating the spread of Vespa velutina nigrithorax and timescales for control in Great Britain

The invasive yellow-legged hornet ( Vespa velutina nigrithorax ) was introduced into France in 2004 from China and has now spread across western Europe and into Great Britain. Between 2016 and 2022, 13 V. velutina nigrithorax nests were sporadically found and destroyed in England. In 2023, 72 nests were found and destroyed by the Animal and Plant Health Agency’s National Bee Unit (NBU) inspectors across southern and northern England. In 2024, 24 nests were found and destroyed. To better understand the potential establishment of V. velutina nigrithorax in Great Britain, a model was developed to simulate its dispersal and the associated control efforts. We simulated public reporting based on the realistic distribution of observers in the landscape, the genetic load due to the presence of diploid males, and continued incursions into a freely breeding population. We estimated the number of years before officials tasked with locating and destroying nests became overwhelmed by the number of nests in the landscape. In the absence of reporting, an undetected population would be large enough to overwhelm control efforts after three to seven years (i.e. the person-days required to locate and destroy nests would exceed those available). When nests were reported by members of the public and beekeepers, control efforts could continue for at least 10 years before becoming overwhelmed – depending on the national reporting probability, the abundance of observers in the landscape, and the annual incursion rate.