Department of Entomology, Cornell University, Ithaca, NY, USA.
Instituto Colombiano de Medicina Tropical, Universidad CES, Sabaneta, 055450, Antioquia, Colombia.
Parasit Vectors. 2019 Sep 18;12(1):455. doi: 10.1186/s13071-019-3710-6.
Aedes aegypti and Aedes albopictus are two globally invasive vectors with similar ecological niches. Encounters between them can result in either competitive exclusion or stable co-existence, but it is unclear what drives these variable outcomes. Larval competition in favor of Ae. albopictus is a main hypothesis for the competitive exclusion of Ae. aegypti observed in some regions. However, the role of oviposition preference in determining the degree of competitive larval interactions in the field is not well understood. In this study, we used a combination of mark-release-recapture methods with ovitraps in the open-field and a semi-field cage to test whether gravid Ae. albopictus seek oviposition sites in response to the presence, species, and density of either conspecific or heterospecific Ae. aegypti larvae in the aquatic habitat. We conducted our study in Medellín, Colombia, where Ae. aegypti is a long-term resident and Ae. albopictus is a recent invader.
In the open-field and semi-field cage experiments, gravid Ae. albopictus showed strong preference for ovitraps with larvae over those without. They consistently preferred ovitraps with higher density of conspecific (Ae. albopictus) larvae and low density of heterospecific (Ae. aegypti) larvae over traps with no larvae or high density of heterospecific (Ae. aegypti) larvae. In the semi-field cage experiment, traps with low density of Ae. albopictus were not preferred more or less than any other trap, but in the open-field experiment they were preferred over traps without larvae.
We demonstrate, through open-field and semi-field cage experiments, that Ae. albopictus are more attracted to oviposition sites with larvae and that the combination of species and density of larvae influence attraction. This demonstrated preference could increase interspecific larval competition as Ae. albopictus actively seek containers with conspecific and heterospecific larvae. Any resulting competition with Ae. aegypti may favor one species over the other and alter the distribution or abundance of both. Because these species vary in vectorial capacity and insecticide resistance, effects of interspecific competition could ultimately impact arbovirus transmission rates and the success of vector control efforts .
埃及伊蚊和白纹伊蚊是两种具有相似生态位的全球入侵媒介。它们之间的相遇可能导致竞争排斥或稳定共存，但不清楚是什么驱动了这些不同的结果。在一些地区观察到的埃及伊蚊竞争排斥，其主要假说为白纹伊蚊幼虫竞争有利。然而，在野外，产卵偏好在决定竞争幼虫相互作用的程度方面的作用尚不清楚。在这项研究中，我们使用标记-释放-捕获方法与野外和半野外笼中的诱卵器相结合，以测试在水生栖息地中，是否有孕埃及伊蚊会根据同种或异种埃及伊蚊幼虫的存在、种类和密度来寻找产卵地点。我们在哥伦比亚麦德林进行了这项研究，在那里，埃及伊蚊是长期居民，而白纹伊蚊是最近的入侵物种。
在野外和半野外笼实验中，孕埃及伊蚊对白纹伊蚊幼虫存在的诱卵器表现出强烈的偏好，而对没有幼虫的诱卵器则不感兴趣。它们始终更喜欢有更高密度同种（白纹伊蚊）幼虫和低密度异种（埃及伊蚊）幼虫的诱卵器，而不是没有幼虫或高密度异种（埃及伊蚊）幼虫的诱卵器。在半野外笼实验中，密度较低的白纹伊蚊诱卵器并不比其他任何诱卵器更受青睐，但在野外实验中，它们比没有幼虫的诱卵器更受青睐。
通过野外和半野外笼实验，我们证明了埃及伊蚊更倾向于在有幼虫的地方产卵，并且幼虫的种类和密度组合会影响吸引力。这种被证明的偏好可能会增加种间幼虫竞争，因为白纹伊蚊会主动寻找有同种和异种幼虫的容器。与埃及伊蚊的任何竞争都可能使一种物种比另一种物种更具优势，并改变两种物种的分布或丰度。由于这些物种在媒介能力和抗药性方面存在差异，种间竞争的影响最终可能会影响虫媒病毒的传播率和病媒控制工作的成功。
