Economic costs of invasive alien ants worldwide

Abstract

Abstract Invasive ants are amongst the most destructive and widespread invaders across the globe; they can strongly alter invaded ecosystems and are responsible for the displacement of numerous native ant species. Several studies have reported that invasive ants can lead to substantial economic costs. In this study, we search, describe and analyze 1,621 reported costs of invasive ants using the InvaCost database. Economic costs, reported since 1930 for 12 ant species in 27 countries, totaled US$ 56.92 billion. The largest costs were associated with two species, Solenopsis invicta and Wasmannia auropunctata (US$ 36.91 and 19.91 billion respectively); and two countries, USA and Australia (US$ 28.62 and 27.94 billion respectively). Potential costs (i.e., expected or predicted costs) constituted the vast majority of the reported costs (80.4%). Overall, damage costs amounted to 96.3% of the total cost, impacting mostly the agriculture, public and social welfare sectors, whereas management costs primarily resulted from post-invasion management (US$ 1.78 billion), with much lower amounts dedicated to prevention (US$ 235.62 million). Beside the taxonomic bias, cost information lacked for ~ 77% of the invaded countries per species, and the geographic coverage of costs was only ~ 18% within invaded countries with costs reported. Our synthesis suggests that the global costs of invasive ants are massive but largely underreported, and thus most likely grossly underestimated. We advocate for more and improved cost reporting of invasive ants through better collaborations between managers, practitioners and researchers, a crucial basis for adequately informing future budgets and improving proactive management actions of invasive ants.