McIntire K M, Juliano S A
School of Biological Sciences, Illinois State University, Normal IL 61760.
Biol Invasions. 2021 May;23(5):1637-1648. doi: 10.1007/s10530-021-02464-0. Epub 2021 Feb 5.
Biological invaders often are accompanied by co-invasive parasites that can alter ecosystem function and established native host-parasite relationships. When these co-invasive parasites establish in a community, they can affect native host fitness and native parasite infection intensity, prevalence, and success within the native host. The mosquito, , is North American host to protozoan parasite, . In geographic regions invaded by the mosquito , may also be infected by co-invasive parasite, . We tested the hypotheses that: 1) The presence of a co-invasive parasite will negatively affect native parasite fitness, yielding decreased infection intensity, prevalence, and infection success, which could be caused by immune induction of the host or inter-parasite competition, and 2) Coinfection with the native and co-invasive parasites will negatively affect host fitness, yielding increased larval development time and decreased survival and reproductive fitness, caused by increased costs of infection. In our coinfection experiments we find that any exposure to the co-invasive parasite resulted in decreased survivorship and increased development time of the host , with or without coinfection by the native parasite. Exposure to both co-invasive and native parasites yielded reduced native parasite infection intensity in the host larva and reduced native parasite propagule production in the resulting male adults. Together, these results indicate not only the potential for the co-invasive parasite to alter the native host-parasite relationship, but to impact native host population dynamics.
生物入侵者通常伴随着共入侵寄生虫，这些寄生虫会改变生态系统功能并破坏已有的本地宿主 - 寄生虫关系。当这些共入侵寄生虫在一个群落中定殖时，它们会影响本地宿主的健康状况以及本地寄生虫在本地宿主内的感染强度、流行率和感染成功率。蚊子是原生动物寄生虫的北美宿主。在蚊子入侵的地理区域，也可能受到共入侵寄生虫的感染。我们检验了以下假设：1）共入侵寄生虫的存在会对本地寄生虫的适应性产生负面影响，导致感染强度、流行率和感染成功率降低，这可能是由宿主的免疫诱导或寄生虫间的竞争引起的；2）本地寄生虫和共入侵寄生虫的双重感染会对宿主的适应性产生负面影响，导致幼虫发育时间延长，生存和繁殖适应性降低，这是由感染成本增加所致。在我们的双重感染实验中，我们发现，无论是否同时感染本地寄生虫，任何对共入侵寄生虫的接触都会导致宿主的存活率降低和发育时间延长。同时接触共入侵寄生虫和本地寄生虫会使宿主幼虫体内的本地寄生虫感染强度降低，并且使所产生的雄性成虫体内的本地寄生虫繁殖体产量减少。总之，这些结果不仅表明了共入侵寄生虫改变本地宿主 - 寄生虫关系的可能性，还表明了其对本地宿主种群动态的影响。
