INRAE, UMR 1349 IGEPP, Le Rheu, France.
Ecole d'Ingénieurs de Purpan, Toulouse, France.
Environ Entomol. 2022 Feb 16;51(1):204-209. doi: 10.1093/ee/nvab122.
Pristine sub-Antarctic islands terrestrial ecosystems, including many endemic species, are highly threatened by human-induced cosmopolitan plant invasion. We propose that native plant suppression could be further facilitated by the subsequent invasion by generalist pest species that could exacerbate their competitive exclusion through the process of apparent competition. By comparing the biological parameters of an invasive aphid species, Myzus ascalonicus, on one native (Acaena magellanica) and one invasive (Senecio vulgaris) plant species, we showed that survival and fecundity were higher and development time lower on the native plant species than on the invasive one. Moreover, comparing the effect of a temperature increase on the population dynamics of M. ascalonicus on the two plants, we showed that the relative profitability of the native species is further amplified by warming. Hence, while pest population doubling time is 28% higher on the invasive plant under current temperature, it would become 40% higher with an increase in temperature of 3°C. Consequently, our findings demonstrate that global warming could exacerbate competitive exclusion of native plants by invasive plants in sub-Antarctic islands by its indirect effect on the apparent competition mediated by generalist phytophagous pests.
原始的南极岛屿陆地生态系统，包括许多特有物种，受到人类诱导的世界性植物入侵的高度威胁。我们提出，通过随后入侵的一般性害虫物种，本地植物的抑制作用可能会进一步得到促进，这些物种可以通过明显竞争的过程加剧它们的竞争排斥。通过比较一种入侵蚜虫物种——麦二叉蚜（Myzus ascalonicus）在一种本地（南极菫菜）和一种入侵（普通千里光）植物物种上的生物学参数，我们表明，与入侵植物相比，该蚜虫在本地植物上的存活率、繁殖力更高，发育时间更短。此外，通过比较温度升高对这两种植物上麦二叉蚜种群动态的影响，我们表明，温度升高会进一步放大本地物种的相对盈利性。因此，虽然在当前温度下，这种蚜虫在入侵植物上的种群倍增时间比在本地植物上高 28%，但如果温度升高 3°C，其种群倍增时间将增加 40%。因此，我们的研究结果表明，全球变暖可能会通过一般性植食性害虫介导的明显竞争的间接影响，加剧南极岛屿上入侵植物对本地植物的竞争排斥。
