Akimoto S
Entomological Institute, Faculty of Agriculture, Hokkaido University, 060, Sapporo, Japan.
Oecologia. 1988 Feb;75(1):44-53. doi: 10.1007/BF00378812.
Galls of more than one species of Eriosoma (Aphidoidea) are found sympatrically even on single trees. Incipient galls are frequently invaded by conspecific and/or allospecific fundatrices. Eriosoma yangi, a component of Eriosoma communities, does not form its own galls but obligatorily usurps those of other species. There were interspecific differences in the timing of gall formation and the spatial distribution of galls. Nevertheless E. yangi fundatrices randomly invaded galls of any Eriosoma species and occupied 33%-41% of galls of each species. When more than one E. yangi fundatrix invaded one gall, mortal fights sometimes occurred. Fundatrices of gall-forming species also seemed to take part in such fights. Fundatrices of gall-forming species had a significant tendency to invade galls of a particular species. However, taking account of niche differences among species, invaders apparently entered available galls at random. Apparently E. yangi fundatrices search an extensive range within a branch for galls, while invaders of gall-forming species search a restricted speciesspecific range. The niche relation of gall-forming species in a northern community containing E. yangi were compared with those in a southern community lacking E. yangi. No obvious difference was found between them, suggesting that parasitism by E. yangi has not influenced niche divergence within the Eriosoma community.
即使在单棵树上也能同时发现多种绵蚜属（蚜总科）形成的虫瘿。初期虫瘿经常会被同种和/或异种的干母侵入。杨氏绵蚜是绵蚜群落的一个组成部分，它并不形成自己的虫瘿，而是强制性地占据其他物种的虫瘿。不同物种之间在虫瘿形成时间和虫瘿的空间分布上存在差异。然而，杨氏绵蚜干母会随机侵入任何绵蚜物种的虫瘿，并占据每个物种虫瘿的33%-41%。当不止一只杨氏绵蚜干母侵入一个虫瘿时，有时会发生致命争斗。形成虫瘿物种的干母似乎也会参与此类争斗。形成虫瘿物种的干母有显著倾向侵入特定物种的虫瘿。然而，考虑到物种间的生态位差异，入侵者显然是随机进入可用虫瘿的。显然，杨氏绵蚜干母会在一个树枝内广泛搜索虫瘿，而形成虫瘿物种的入侵者则在一个受限的特定物种范围内搜索。将含有杨氏绵蚜的北方群落中形成虫瘿物种的生态位关系与缺乏杨氏绵蚜的南方群落中的进行了比较。两者之间未发现明显差异，这表明杨氏绵蚜的寄生并未影响绵蚜群落内的生态位分化。
