Effects of aphid parasitism on host plant fitness in an aphid-host relationship.

Aphids are serious agricultural insect pests which exploit the phloem sap of host plants and thus transmit pathogens to their hosts. However, the degree to which aphid parsitism affects the fitness of the host plants is not well understood. The aphid, Macrosiphoniella yomogicola, parasitizes the mugwort Artemisia montana in Japan. During summer most mugworts carry aphids, but most aphid colonies die out after the budding of A. montana inflorescences in late summer. A few aphid colonies survive to late autumn, at which point sexuparae appear to later lay overwintering eggs after copulation. The death of the aphid colonies seems to cause by biochemical changes in the phloem sap in the host plant coincident with the budding of inflorescences. The surviving aphid colonies may suppress the budding of inflorescences to allow persistence of their genetic line into the following year. Our investigations demonstrate that aphid parasitism did not affect host plant growth, but that it did signific...

蚜虫是一类严重危害农业的昆虫害虫，它们通过取食寄主植物的韧皮部汁液（phloem sap），并将病原体传播至寄主植物体内。然而，蚜虫寄生对寄主植物适合度的影响程度目前仍未得到充分阐明。在日本，菊小长管蚜（Macrosiphoniella yomogicola）会寄生魁蒿（Artemisia montana）。夏季多数魁蒿植株都会被该蚜虫侵染，但在夏末魁蒿花序萌发后，绝大多数蚜虫种群会消亡。仅有少量蚜虫种群能够存活至深秋，此时会产生有性蚜（sexuparae），经交配后产下越冬卵。蚜虫种群的消亡似乎是由寄主植物韧皮部汁液的生化变化所引发，该变化与花序萌发同步发生。存活的蚜虫种群或可抑制花序萌发，使其遗传谱系得以延续至次年。本研究结果表明，蚜虫寄生并未对寄主植物的生长造成显著影响，但却能显著……