School of Biological Sciences, Behavior, Ecology, Evolution, and Systematics Section, Illinois State University, Normal, IL 61761-4120, USA.
Oecologia. 2010 Sep;164(1):221-30. doi: 10.1007/s00442-010-1624-2. Epub 2010 Apr 10.
Geographic variation in species interactions can have major effects on species distributions and can be important for the resistance of resident communities to invasive species. We tested the hypothesis that coexistence or replacement of a resident North American mosquito Aedes aegypti with the invasive Aedes albopictus is affected by interpopulation variation in the inherent competitive ability of A. aegypti and variation in the fecundity-size relationship. We postulated that such variation creates differential population-level outcomes of competition with A. albopictus. We compared competitive abilities of eight North American populations of A. aegypti, four populations sympatric to A. albopictus, and four populations allopatric to A. albopictus. Competition among larvae from each A. aegypti population and a single A. albopictus population was tested in laboratory microcosms in a response-surface design. We found origin of A. aegypti influences its competitive response to competition from A. albopictus and competitive effect on A. albopictus. A. aegypti from allopatric sites preformed better in competition with A. albopictus than did A. aegypti from sympatric sites because they had a stronger average effect on A. albopictus. This average was strongly influenced by the allopatric population from Miami. Competitive effect and response were uncorrelated among populations, indicating inconsistent ranking of A. aegypti in competitive effect and response. Although A. albopictus is generally a superior competitor to A. aegypti, a stronger competitive effect of particular A. aegypti populations on invading A. albopictus may contribute to competition-mediated biotic resistance to the invader. These results suggest that interpopulation variation in competitive ability of A. aegypti may contribute to failure of A. albopictus to invade parts of the southeastern United States and offer evidence of a contribution to biotic resistance by an inferior competitor. Geographic variation in competitive ability may be common and one general cause of variation in invasion success and impact.
物种相互作用的地理变异可能对物种分布产生重大影响，并且可能对驻留社区抵御入侵物种的能力很重要。我们检验了以下假设：即与北美本地蚊子埃及伊蚊共存或取代的现象是否会受到埃及伊蚊种群间固有竞争能力的变化和繁殖-体型关系变化的影响。我们推测，这种变化会导致与白纹伊蚊竞争的种群水平结果存在差异。我们比较了 8 个北美埃及伊蚊种群、4 个与白纹伊蚊共存的种群和 4 个与白纹伊蚊隔离的种群的竞争能力。在实验室微生境中，采用响应面设计，测试了每个埃及伊蚊种群和一个白纹伊蚊种群的幼虫之间的竞争情况。我们发现埃及伊蚊的起源影响其对白纹伊蚊的竞争反应和对白纹伊蚊的竞争效应。来自隔离地点的埃及伊蚊在与白纹伊蚊竞争时表现更好，因为它们对白纹伊蚊的平均影响更强。这种平均值受到迈阿密隔离种群的强烈影响。种群之间的竞争效应和反应没有相关性，表明埃及伊蚊在竞争效应和反应中的排名不一致。尽管白纹伊蚊通常是埃及伊蚊的优势竞争者，但特定埃及伊蚊种群对白纹伊蚊的竞争效应较强，可能有助于对入侵物种的生物抗性。这些结果表明，埃及伊蚊竞争能力的种群间变异可能导致白纹伊蚊无法入侵美国东南部的部分地区，并为弱势竞争者对生物抗性的贡献提供了证据。竞争能力的地理变异可能很常见，是入侵成功和影响变化的一个普遍原因。
