The effects of native species community on spread of invasive species by comparisons of original and remote populations.

利用入侵的瓢虫种类进行了一系列的田间和实验室研究，以了解这些入侵物种建立和传播的机制，特别是它们与天敌和原始和偏远地区本地瓢虫物种的相互作用，例如：(1)七星瓢虫和异色瓢虫对北美本地物种的影响；(2)二点瓢虫与日本本地物种的相互作用；(3)黑斑瓢虫与日本本地物种的相互作用；(4)食草性瓢虫在原始种群(危地马拉)和偏远种群(日本)中的死亡因素。还预测了入侵物种可能的命运。在(1)中，异色瓢虫与北美本地物种相比具有较强的攻击性和通用性，这表明与异色瓢虫共享栖息地的原住民的丰度下降是由于异色瓢虫在行会内的捕食。此外，异色瓢虫有可能在北美和欧洲进一步传播。在(2)中，二点姬蜂与日本本土物种异色斑潜蝇共享栖息地，并经常遭受异色斑潜蝇的行内捕食，这表明二斑潜蝇在日本进一步传播的可能性不大。在(3)中，日本本土种六斑鱼对猎物和栖息地资源的竞争可能是入侵黑线姬鼠的竞争对手。然而，六斑拟线虫的丰度相当低，这表明黑线亚种的传播取决于它们的猎物--立方异尖线虫的分布，后者也是入侵物种，在日本迅速传播。也就是说，黑热病很可能在日本琉球群岛进一步蔓延。在(4)中，在日本，变色拟小蜂经常被当地的寄生蜂寄生，这有效地调节了变色拟小蜂的丰度和传播，这表明它不太可能在日本迅速传播。

A series of field and laboratory studies using invasive species of ladybird was conducted for understanding of mechanisms that enable those to establish and spread, especially their interactions with natural enemies and native ladybird species in original and remote area, such as (1) The effects of Coccinella septempunctata and Harmonia axyridis on native species in North America, (2) Interaction Adalia bipunctata with native species in Japan, (3) Interactions Olla v-nigrum with native species in Japan, and (4) Mortality factors of herbivore ladybird, Epilachna varivestis, in original (Guatemala) and remote populations (Japan). Possible fate of invasive species is also predicted. In (1), H.axyridis is relatively aggressive and generalist compared with native species in North America, suggesting that decrease in abundance of those natives, which share habitat with H.axyridis, due to intraguild predation by H.axyridis. In addition, further spread of H.axyridis in North America and Europe is likely. In (2), A.bipunctata share the habitat with H.axyridis, native species in Japan, and often suffer from intraguild predation by H.axyridis, suggesting that further spread of A.bipunctatat in Japan is unlikely. In (3), Menochilus sexmaculatus, a native species of Japan, can be a possible competitor of invasive O.v-nigrum for prey and habitat resources. However, considerably low abundance of M.sexmaculatus suggests that spread of O.v-nigrum depends on distribution of their prey, Heteropsylla cubana, also invasive species and rapidly spreading in Japan. That is, further spread of O.v-nigrum in Ryukyu Islands, Japan, is likely. In (4), in Japan, E.varivestis is often parasitized by a native parasitoid wasp, which efficiently regulates abundance and spread of E.varivesti, suggesting that its rapid spread in Japan, is unlikely.