Eradicating Little Fire Ants (Wasmannia Auropunctata) from the Island of Kaua`I, Hawai`I: Process, Challenges, and Results to Date

First detected on the Island of Kauai in 1999, the little fire ant (Wasmannia auropunctata) has persisted despite early attempts at eradication by state agencies. A multi-agency collaboration was formed in 2011 to develop and implement a two-phase eradication plan. The infestation was delimited to 4.02 ha of rural residences and steep coastline habitat. Treatments regimens were divided between easily accessible infested areas (Phase I) and steep areas requiring rope safety systems (Phase II). The eradication plan included ground and arboreal treatment technologies and long-term post-treatment monitoring. Treatments consisted of broadcasting baits containing s-methoprene (0.25% a.i.), indocaxarb (0.18% a.i), or hydramethylnon (0.73% a.i.) eight times over the course of 12 months. Treatments effectively reduced the population to below detectable levels throughout much of the treatment area, however isolated remnant colonies were detected as recently as September 2019. Remnant colonies were associated with specific site features known to be difficult to treat, such as tall palm trees and large mulch piles. On one occasion, in 2017, two little fire ant detections were confirmed outside of the original treatment area, where no little fire ants had been detected before; highlighting the ability for little fire ants to remain undetected for many years. Current results stress the importance of long-term commitment to post-treatment monitoring and expanded surveys. We recommend development and incorporation of novel detection methods which could increase accuracy and improve efficiency of monitoring and detection surveys.

ETAPAS DO MÉTODO CIENTÍFICO COM ALUNOS DO ENSINO FUNDAMENTAL

O objetivo deste trabalho foi estimular o saber científico nos educandos desde a Educação Básica de Ensino através do desenvolvimento das etapas dos métodos científicos. Buscou-se descrever, neste trabalho, o relato sobre um conjunto de ações investigativa, seguindo os passos do Método científico. O método utilizado foi a observação de uma publicação em site sobre o comportamento de uma espécie de formiga (Camponotus terebrans), foi levantado o problema (Será que a formiga pixixica (Wasmannia auropunctata) também prefere xixi do que água açucarada?), elaboração de hipóteses, início de experimentação, análise dos resultados, aceitação ou rejeição da hipótese. O comportamento das formigas (W. auropunctata) observadas nas quatro experiências, levou os alunos a aceitarem a hipótese "a formiga prefere água açucarada do que xixi" diferente do comportamento da formiga C. terebrans relatada no site https://www.valedoitaunas.com.br/artigo/formigas-preferem-ingerir-xixi-a-acucar-e-isso-faz-bem-ao-planeta. Firmando-se nos relatórios, percebe-se que os educandos compreenderam, através da prática, o assunto que estava exposto no livro didático, bem como demonstraram um caráter científico.

Economic costs of invasive alien ants worldwide

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.

Effects of the Invasive Little Fire Ant (Wasmannia auropunctata) on Ant Community Composition on UF Campus

Invasive species are a serious threat to Florida’s native ecosystems and can have significant economic impacts. The invasive little fire ant (Wasmannia auropunctata) was first observed on the University of Florida’s campus in the Field and Fork Gardens in Summer 2018 and a targeted eradication of this population began in Fall 2018. This project aimed to compare ant community composition in invaded and uninvaded areas to better understand how ant invasions affect native ant communities. For comparison with Field and Fork Gardens invaded sites, four additional sites on UF’s campus were surveyed for ants through leaf litter sampling. Samples were sorted and all ants identified to the genus level; samples from invaded sites were identified to species. In samples from invaded sites, the community had lower species richness and a lower relative abundance of ant species compared to uninvaded communities. Determining how the invasion of the little fire ant affects ant communities is important as invasive ants do not fill the same ecosystem roles as native ants, such as seed dispersal and mutualist interactions. Data on community composition in uninvaded areas could be useful in efforts to restore a site after eradication has been achieved.