4. Environmental Impacts 5. Urban Ecosystems and Human Health 165 leading the Red Imported Fire Ants in Mainland China, Hong Kong and Macau is well known for causing significant damage to natural and agricultural ecosystems (Stuble et al., 2010). In the USA, RIFA is known to have caused a severe decline in crop production through predation on different plant parts such as roots, stems, flowers and fruits, with estimated reductions of up to 15 to 33% in soybeans, 20 to 35% in potatoes and 50% in eggplant (Adams, 2019). Moreover, this species also indirectly damages its mutualistic association with sap-sucking insects, such as aphids and mealybugs, and also reduces the efficiency of biological control by preying on natural biological control agents (Parys & Johnson, 2012). As a result, RIFA’s for presence generates significant economic costs agricultural production, estimated at $200 million per year for its control in the USA alone, with an additional annual loss of $6 billion (Pimentel et al., 2005; Drees & Lard, 2006). through is butterflies to identify these odors as a potential threat remains unknown, suggesting the potential need for further studies to determine their response to these chemical cues (Wu et al., 2014). 4.1 Impact on Agricultural Systems invicta Solenopsis crop production In Hong Kong, a central trading hub for Asian and global markets, the agricultural industry is relatively small, covering around 698 hectares and generating about $44.7 million in crop production (Agricultural Fisheries and Conservation Department The Government of the Hong Kong Special Administrative Region, 2017). The presence of RIFA on local farms in Hong Kong has brought about various economic challenges, such as yield reduction and increased management costs. Although Hong Kong’s agricultural sector is smaller and more geographically scattered than those of the USA or mainland China, the potential significant, especially considering the role of urban farming in local food security and biodiversity (Chan & Guénard, 2020). Understanding how RIFA impacts agricultural practices in a dense urban environment like Hong Kong could provide valuable insights for developing tailored management strategies to mitigate these threats. for disruption RIFA is known for damaging crops at different stages, including seedlings and fruits, sometimes high-income fruit, or even high-value crops. Feeding on germinating seeds and seedlings reduces germination success and leads to stunted growth and development. Experiments on the selective feeding behavior of S. invicta on various crops (Huang et al., 2010) show that this ant prefers Sesamum indicum and sometimes removes 100% of the seeds, rendering them nonviable (Huang et al., 2010). Solenopsis invicta generally transports seeds a lesser distance, damages or destroys them, or discards them in locations unfavorable for germination or vulnerable to seed predators (Stuble et al., 2010). As a seed harvester, S. invicta prefers seeds containing higher levels of fat and protein, such as those from Raphanus sativus or of the Brassica genus (B. alboglabra, B. rapa, B. oleracea, B. juncea, or B. campestris) (Ma, 2011). This selective feeding preference significantly reduces these seeds’ germination rates, leading to lower crop yields. Mutualistic associations between ants and insects, mainly from the Hemiptera order, often involve ants protecting these insects from their natural enemies (Tena et al., 2013). This can also lead to a reduction in herbivory by herbivores as the ants prey on them, increasing plant fitness and reproduction (Chamberlain & Holland, 2009). However, S. invicta can protect pest species, such as Phenacoccus solenopsis (Huang et al., 2011, Cheng et al., 2013). By safeguarding these pests, S. invicta favors the spread of other invasive species, further disrupting natural and agricultural ecosystems. Future research should focus on understanding the long-term ecological impacts of these mutualistic relationships, particularly how they contribute to the spread and establishment of different pest species. Additionally, future research should explore effective management strategies that target mutualistic associations to mitigate the damage caused by S. invicta and its associated pest species. 5.1 Infestation of Urban Landscapes Solenopsis invicta has become a significant pest in Chinese urban landscapes, posing threats to public health, infrastructure and biodiversity. Notably, increased stings and consequent allergic reactions have been reported among individuals involved in outdoor activities, such as farmers, who frequently contact these ants during work, leading to physical and psychological stress (Chan & Guénard, 2020). Large colonies in public spaces also directly these areas become hazardous due to the risk of ant stings. Reports from various regions of China, including Guangzhou and Shenzhen, highlight individuals, particularly children and the elderly, have experienced to severe hospitalizations and significant medical costs (Zhang et al., 2007). For example, a couple gathering bananas in the Nansha District required two weeks of hospitalization, while a child in the same district suffered fever and shock after being stung. Similar cases and severe reactions have been documented in other regions (Zhang et al., 2007). reactions This ant’s aggressive behavior can damage infrastructure such as electrical equipment and various green spaces (gardens and parks), leading to costly maintenance (Bradshaw et al., 2016). For instance, the costs associated with fires and damage to electrical equipment are said to have totaled $146.5 million threaten residents, as incidents where invicta stings, to S.
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