Juliano Steven A, Lounibos L Philip, O'Meara George F
Department of Biological Sciences, Behavior, Ecology, Evolution, and Systematics section, Illinois State University, Normal, IL 61790-4120, USA.
Oecologia. 2004 May;139(4):583-93. doi: 10.1007/s00442-004-1532-4. Epub 2004 Mar 16.
We tested whether interspecific competition from Aedes albopictus had measurable effects on A. aegypti at the typical numbers of larval mosquitoes found in cemetery vases in south Florida. We also tested whether the effect of interspecific competition from A. albopictus on A. aegypti differed between sites where A. aegypti either persists or went extinct following invasion by A. albopictus. Similar experiments manipulating numbers of A. albopictus in cemetery vases were conducted at three sites of A. aegypti persistence and three sites where A. aegypti was apparently extinct. The experiments were done using numbers of larvae that were determined by observed numbers of larvae for each site, and with resources (leaf detritus) that accumulated in experimental vases placed into each field site. In both the early rainy season (when number of mosquito larvae was low) and the late rainy season (when number of mosquito larvae was high), there was a significant effect of treatment on developmental progress of experimental A. aegypti. In the late rainy season, when numbers of larvae were high, there was also a significant effect of treatment on survivorship of A. aegypti. However, the competition treatment x site type (A. aegyptipersists vs extinct) interaction was never significant, indicating that the competitive effect of A. albopictus on A. aegypti did not differ systematically between persistence versus extinction sites. Thus, although competition from A. albopictus is strong under field conditions at all sites, we find no evidence that variation in the impact of interspecific competition is associated with coexistence or exclusion. Interspecific competition among larvae is thus a viable explanation for exclusion or reduction of A. aegypti in south Florida, but variation in the persistence of A. aegypti following invasion does not seem to be primarily a product of variation in the conditions in the aquatic environments of cemetery vases.
我们测试了在佛罗里达州南部墓地花瓶中发现的典型蚊幼虫数量下，白纹伊蚊的种间竞争对埃及伊蚊是否有可测量的影响。我们还测试了白纹伊蚊对埃及伊蚊的种间竞争影响在埃及伊蚊持续存在或在白纹伊蚊入侵后灭绝的地点之间是否存在差异。在埃及伊蚊持续存在的三个地点和埃及伊蚊明显灭绝的三个地点，进行了类似的操纵墓地花瓶中白纹伊蚊数量的实验。实验使用的幼虫数量是根据每个地点观察到的幼虫数量确定的，并使用放置在每个野外地点的实验花瓶中积累的资源（树叶碎屑）。在雨季早期（蚊幼虫数量较低时）和雨季后期（蚊幼虫数量较高时），处理对实验埃及伊蚊的发育进程都有显著影响。在雨季后期，当幼虫数量较高时，处理对埃及伊蚊的存活率也有显著影响。然而，竞争处理×地点类型（埃及伊蚊持续存在与灭绝）的相互作用从未显著，这表明白纹伊蚊对埃及伊蚊的竞争影响在持续存在地点与灭绝地点之间没有系统差异。因此，尽管在所有地点的野外条件下，白纹伊蚊的竞争都很强，但我们没有发现证据表明种间竞争影响的差异与共存或排斥有关。幼虫之间的种间竞争因此是佛罗里达州南部埃及伊蚊被排斥或数量减少的一个可行解释，但埃及伊蚊在入侵后持续存在的差异似乎主要不是墓地花瓶水生环境条件差异的产物。
