Abstract：
Co-invasion, characterized by the simultaneous introduction of hosts and parasites with the latter establishing themselves in native hosts, is a phenomenon of ecological concern. Rattus rattus, a notorious invasive species, has driven the extinction and displacement of numerous avian and mammalian species and serves as a key vector for diseases affecting both humans and wildlife. Among the parasites hosted by R. rattus are fleas, which exhibit obligate parasitic behaviour, a generalist nature and high prevalence, increasing the likelihood of flea invasion. Simultaneously, invasive species can serve as hosts for native parasites, leading to potential amplification or dilution of parasite populations in the environment. In Chile, R. rattus has been present since the 17th century because of the arrival of the Spanish colonizers through the ports and has spread throughout urban, rural and wild Chilean territories. This study aims to evaluate whether co-invasion of native fleas of invasive rats occurs on native rodents in Chile and to determine whether black rats have acquired flea native to Chile during their invasion. For this, we captured 1132 rodents from 26 localities (20° S-53° S). Rattus rattus was found coexisting with 11 native rodent species and two species of introduced rodents. Among the native rodents, Abrothrix olivacea and Oligoryzomys longicaudatus exhibited more extensive sympatry with R. rattus. We identified 14 flea species associated with R. rattus, of which only three were native to rats: Xenopsylla cheopis, Leptopsylla segnis and Nosopsyllus fasciatus. These three species presented a higher parasite load in black rats compared to native fleas. Leptopsylla segnis and N. fasciatus were also found associated with native rodent species that cohabit with R. rattus. The remaining species associated with R. rattus were fleas of native rodents, although they were less abundant compared to those associated with native rodents, except for Neotyphloceras pardinasi and Sphinctopsylla ares. Although there has been evidence of flea transmission from rats to native species, the prevalence and abundance were relatively low. Therefore, it cannot be definitively concluded that these fleas have established themselves in native rodent populations, and hence, they cannot be classified as invasive fleas. This study underscores R. rattus\' adaptability to diverse environmental and geographical conditions in Chile, including its capacity to acquire fleas from native rodents. This aspect has critical implications for public health, potentially facilitating the spread of pathogens across various habitats where these rats are found.
摘要：
共同入侵,其特征是同时引入宿主和寄生虫，后者在本地宿主中建立自己，是一种生态问题。Rattusrattus,一个臭名昭著的入侵物种,导致了许多鸟类和哺乳动物物种的灭绝和流离失所，并成为影响人类和野生动物的疾病的关键媒介。在R.rattus寄养的寄生虫中有跳蚤，表现出专性寄生行为，通才性质和高流行率，增加跳蚤入侵的可能性。同时,入侵物种可以作为本地寄生虫的宿主，导致环境中寄生虫种群的潜在放大或稀释。在智利,由于西班牙殖民者通过港口的到来，R.rattus自17世纪以来一直存在，并遍及整个城市，智利的乡村和野生领土。这项研究旨在评估智利的本地啮齿动物是否发生了入侵大鼠的本地跳蚤的共同入侵，并确定黑鼠在入侵期间是否获得了智利本地跳蚤。为此，我们从26个地区（20°S-53°S）捕获了1132只啮齿动物。发现Rattusrattus与11种本地啮齿动物和2种引入的啮齿动物共存。在本地啮齿动物中，龙舌兰和Ligoryzomyslongicaudatus与R.rattus表现出更广泛的共生关系。我们确定了14种与R.rattus相关的跳蚤，其中只有三种是大鼠的原生产品：Xenopsilacheopis，Leptopsylnasegnis和Nosopsylusfasciatus。与本地跳蚤相比，这三个物种在黑鼠中的寄生虫负荷更高。还发现了Leptopsylnasegnis和N.fasciatus与R.rattus同居的本地啮齿动物。与R.rattus相关的其余物种是本地啮齿动物的跳蚤，尽管与本地啮齿动物相比，它们的数量较少，除了Neotyphloceraspardinasi和Sphinctoptyplares。尽管有证据表明跳蚤从老鼠传播到本地物种，患病率和丰度相对较低。因此,无法明确地得出结论，这些跳蚤已经在本地啮齿动物种群中确立了自己的地位，因此，它们不能被归类为侵入性跳蚤。这项研究强调了R.rattus对智利不同环境和地理条件的适应性，包括从本地啮齿动物获得跳蚤的能力。这一方面对公众健康有重要影响，可能促进病原体在发现这些老鼠的各个栖息地的传播。
