Sentinel site strategy for the early detection of pest and invasive ants

Early detection of invasive ant infestations can greatly reduce resource requirements and costs associated with management. The National Electric Ant Eradication Program (NEAEP) has used a targeted surveillance strategy since its inception to focus surveillance efforts at ‘sentinel sites’ where high risk carriers of electric ant (Wasmannia auropunctata) aggregate, and/or could support pathways for extensive spread. In addition to early detection, sentinel sites can prioritise and focus future surveillance efforts when a target species is detected within a catchment. In this paper, the NEAEP sentinel site strategy is outlined, and field effort and diagnostic data reviewed. Since the financial year 2011/ 2012 the Program has surveyed a total of 290 sentinel sites. As funding to the program increased, the number of visits to sentinel sites also increased. In the last 5 years, we have detected W. auropunctata at sentinel sites 32 times and of these detections, waste transfer stations accounted for 34.21%; illegal dumping 21.05%, and plant nurseries 15.79%. After a detection at a sentinel site, proactive surveillance, focused on the sentinel site catchments, located a further 44 infested areas, with one catchment suspected to contain a population of W. auropunctata that is yet to be detected. It is believed that this sentinel site strategy can be used to detect other ant species, as evidenced by the detections of established invasive species at multiple NEAEP sentinel sites; African big-headed ant (Pheidole megacephala), and Singapore ant (Trichomyrmex destructor).