3.4 Ecosystem Disruptor 135 in White-footed ant biology and management is the most important household pest together with L. humile in South Africa (Prins et al., 1990). Household intrusion by T. albipes or T. difficilis is also a problem in Hawaii and North America (Hedges, 1997; Klotz et al., 2008; Warner & Scheffrahn, 2004, 2005; Warner et al., 2019). Reports on Technomyrmex damage to electronic devices include breakdown of air conditioners caused by T. difficilis in the U.S. (Hedges, 1997) and malfunction of relays caused by T. albipes in New Zealand (Little, 1984). develops symbiotic relationships with hemipteran insects such as aphids and mealybugs, and protects them from natural enemies, leading to outbreaks of these sap-sucking pests and damage to crops. On Okinawa Island, T. brunneus increases damage the pineapple mealybug Dysmicoccus brevipes (Takara & Azuma, 1967). Similar problems could be caused in other agricultural environments (e.g., horticultural crop fields and orchards) as well as urban environments (e.g., house gardens and urban greenery). Technomyrmex brunneus appears to rely heavily on honeydew secreted by the hemipteran insects. Actually, T. brunneus was the most frequent visitor of honeydew-secreting hemipteran insects on Chichi-jima Island of the Ogasawaras (Ohnishi et al., 2018). of Kagoshima Prefecture, Kyushu (e.g., Fukumoto et al., 2023). 3.3 Agricultural Pest Technomyrmex Technomurmex albipes brunneus to pineapples by protecting Technomyrmex albipes and T. difficilis have caused agricultural damage in various parts of the world, including South Africa, Hawaii, mainland U.S. and New Zealand (Samways et al., 1982; Charles, 1993; Warner & Scheffrahn, 2004, 2005; Klotz et al., 2008; Wetterer, 2013; Warner et al., 2019). In Sri Lanka, T. difficilis causes agricultural damage by tending D. brevipes, similar to the relationship between T. brunneus and D. brevipes on Okinawa Island (Sulaiman, 1997). A previous study in a 11.4 ha park of Hioki City, Kagoshima Prefecture, suggests that T. brunneus has a strong impact on native ant fauna (Harada, 2020). In this park, T. brunneus was absent in the surveys from 2001 to 2006 but detected in 2009, and had become the most dominant ant species by 2020. In a comparison of ants collected from trees between 2001 and 2020 (224 and 167 individual trees, respectively), four out of 15 ant species disappeared, and the frequency of six other species decreased by more than 80%. In the Yanbaru region of northern Okinawa Island, T. brunneus is established along forest edges, where it develops relationship with hemipteran insects (Tanaka et al., 2011). This might affect relationships among native organisms. strong mutualistic a Technomyrmex albipes and T. difficilis are regarded as disruptors of native ecosystems (Hansen & Müller, 2008). In orchards on Borneo Island, T. albipes disrupts the spatial distribution of native arboreal ant communities and reduces ant species richness (Rahim & Ohkawara, 2019). In New Zealand, T. albipes develops a strong mutualistic relationship with hemipteran insects and affects not only fruit trees but also other plants, including native ones (Charles, 1993; Lester et al., 2003). 4.1 Reproductive System – Extreme Polygyny Technomyrmex brunneus has complex reproductive system, where winged queens found new colonies at distant sites after their nuptial flight but at the same time worker-like wingless queens expand the colony by founding new nests near their natal nests (Yamauchi et al., 1991; Yamane & Fukumoto, 2017). Like many other ant species, winged queens and males undertake nuptial flight. After copulation outside their natal nests, the queens abandon their wings and found new colonies. Nuptial flight occurs from June to July on Okinawa and the Ogasawara Islands, July on Hachijo Island, and August in Kagoshima Prefecture (Yamauchi et al., 1991; Tsuji & Yamauchi, 1994; Shimana, 2010; Terayama et al., 2021a; Hisasue & Tsuji, 2024). While the founding queen reproduces workers, she also reproduces numerous worker-like queens called intercastes. The founding queen dies at a relatively early time and the intercastes take over the reproduction of workers and reproductive castes (Tsuji & Yamauchi, 1994). The intercastes have intermediate morphological characteristics between winged queens and workers with some variations (Fig. 2). However, the intercastes lack wings and thus are not capable of nuptial flight. Tsuji et al. (1991) classified the intercastes into three types: major intercastes with three ocelli, medium intercastes with one ocellus, and minor intercastes without ocelli. The average number of ovarioles is 11, nine and seven for the major, medium and minor intercastes, respectively, while it is 20 for the winged queens. Tsuji et al. (1991) found that more than 95 percent of the dissected intercastes had mated their their natal nests and had sperm within spermathecae. Together with the intercaste queens, wingless males are also reproduced (Fig. 2). These intercaste females and wingless males are reproduced through all seasons except winter. Intercaste females and wingless males have significantly smaller copulatory organs than winged females and males, and thus wingless males can mate only with intercaste females (Ogata et al., 1996; Yamane et al., 2018). The female-to-male ratio is 1:1 among the winged queens and males, while it is 5:1 or even more biased toward females among the intercastes in typical colonies (Tsuji & Yamauchi, 1994). This female-biased 4. Ecology of T. brunneus
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