Eradication and Control Strategies for Red Imported Fire Ants (Solenopsis invicta) in Taiwan

The implementation of robotic dogs in automatic detection and surveillance of red imported fire ant nests

BACKGROUND

The Red Imported Fire Ant (RIFA), scientifically known as Solenopsis invicta, is a destructive invasive species causing considerable harm to ecosystems and generating substantial economic costs globally. Traditional methods for RIFA nests detection are labor-intensive and may not be scalable to larger field areas. This study aimed to develop an innovative surveillance system that leverages artificial intelligence (AI) and robotic dogs to automate the detection and geolocation of RIFA nests, thereby improving monitoring and control strategies.

RESULTS

The designed surveillance system, through integrating the CyberDog robotic platform with a YOLOX AI model, demonstrated RIFA nest detection precision rates of >90%. The YOLOX model was trained on a dataset containing 1118 images and achieved a final precision rate of 0.95, with an inference time of 20.16 ms per image, indicating real-time operational suitability. Field tests revealed that the CyberDog system identified three times more nests than trained human inspectors, with significantly lower rates of missed detections and false positives.

CONCLUSION

The findings underscore the potential of AI-driven robotic systems in advancing pest management. The CyberDog/YOLOX system not only matched human inspectors in speed, but also exceeded them in accuracy and efficiency. This study's results are significant as they highlight how technology can be harnessed to address biological invasions, offering a more effective, ecologically friendly, and scalable solution for RIFA detection. The successful implementation of this system could pave the way for broader applications in environmental monitoring and pest control, ultimately contributing to the preservation of biodiversity and economic stability. © 2024 Society of Chemical Industry.

Pest categorisation of Solenopsis invicta

The EFSA Panel on Plant Health performed a pest categorisation of Solenopsis invicta Butler (Hymenoptera: Formicidae) the red imported fire ant, for the EU territory. S. invicta is native to central South America and has spread to North and Central America, East Asia and Australia where it is recognised as a major invasive species causing serious environmental impacts to biodiversity and harming horticultural crops such as cabbage, eggplant and potatoes. It can girdle and kill young citrus trees. S. invicta is not listed as a Union quarantine pest in Annex II of Commission Implementing Regulation (EU) 2019/2072. However, the European Scientific Forum on Invasive Alien Species lists S. invicta as a species of Union concern (Commission Implementing Regulation (EU) 2022/1203). Like other ant species, S. invicta is a social insect commonly creating colonies in the soil. Long-distance spread in the Americas has been attributed to nests being carried in soil accompanying plants for planting, or simply in soil alone. S. invicta could enter the EU via conveyances carrying a wide range of goods if the conveyance is contaminated with soil or has been in close contact with soil, and with plants for planting in soil or growing media. Climatic conditions in large parts of the southern EU are suitable for establishment and spread would occur when mated females disperse to form new colonies. If S. invicta established in the EU, losses to horticultural crops would be expected in addition to losses to biodiversity. The impacts of S. invicta go beyond plant health with the ant attacking new-born, hatching, weak or sick animals. Stings can cause allergic reactions in humans and are a public health issue. However, such factors are outside the scope of a pest categorisation. S. invicta satisfies the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest.

Impact of invasive ant species on native fauna across similar habitats under global environmental changes

Biotic invasions can predominantly alter the dynamics, composition, functions, and structure of natural ecosystems. Social insects, particularly ants, are among the most damaging invasive alien species. Invasive ant species are among the supreme threats to ecosystems. There are about 23 species of invasive ants recorded worldwide, according to the ant invasive databases. The ecological impacts of invasive ants comprise predation, hybridization, and competition with native species that changes the ecosystem processes with the biodiversity loss and upsurge of pests. The effects of invasion on native fauna in the same habitats might be catastrophic for the native community through various ecological mechanisms, e.g., habitat disturbance, resource competition, limiting the foraging activity of native species, and various other indirect mechanisms of invasive species. Invasive species may have harmful impacts on habitats and devastating effects on natural flora and fauna, and stopping these new species from being introduced is the most effective way to deter future invasions and maintain biodiversity. This paper reviews the literature to evaluate the effects of invasive ant species on the native species, including vertebrates, invertebrates, and plants sharing the same habitats as the non-native species under global environmental changes. We also highlighted the various management strategies that could be adopted in minimizing the adverse effects of these invasive ant species on the natural ecosystem. To this end, strategies that could regulate the mode and rate of invasion by these alien ant species are the most effective ways to deter future invasions and maintain biodiversity.

Establishment and Social Impacts of the Red Imported Fire Ant, Solenopsis invicta, (Hymenoptera: Formicidae) in Taiwan

The first report of the red imported fire ant (RIFA), Solenopsis invicta Buren, in Taiwan was in the city of Taoyuan in 2003. The government has made great efforts to bring RIFA-infested areas under control. RIFA has gradually spread outward since its discovery, but it is still confined in northern Taiwan, in part due to the control efforts. RIFA is well established in densely populated environments (i.e., urban areas), causing damage to public utilities and significantly affects the inhabitants of Taiwan. Out of 10,127 human encounters with RIFA reported by the Plant Pest Information Management System in the Bureau of Animal and Plant Health Inspection and Quarantine, Council of Agriculture, Executive Yuan, 3819 (37.71%) persons were stung, with 834 (21.8%) persons exhibiting wheal-and-flare reaction (swelling and redness of the skin). Among the victims, 288 (7.5%) sought medical care, and about 21 (0.6%) developed severe cellulitis and urticaria. Unexpectedly, 2.8% (106) of the victims exhibited anaphylactic shock, which was higher than previously reported cases (1%). The high anaphylactic shock percentage was probably because most victims were elderly farmers or because Asian people have higher sensitivity to the RIFA sting. RIFA is well adapted to the environmental conditions in Taiwan, which makes it extremely difficult (if not impossible) to eradicate. The management of RIFA in the future should focus on lowering the speed of spread to mitigate possible dangers to the inhabitants. Six major challenges of RIFA management in Taiwan are also discussed.