Comparison of behavior between ant-dependent and independent aphids

在行为和形态上比较了蚂蚁与其独立同胞的行为，但没有发现显著的差异。这可能是因为与蚂蚁有关的互惠关系通常是有条件的或间接的。因此，从这一角度出发，本研究对一些与蚂蚁有关的互惠现象进行了研究。主要研究结果如下：1)在受蚂蚁侵扰的栎树上，依赖蚂蚁的蚜虫数量显著增加。然而，蚂蚁减少了对树叶和橡子有害的非蚂蚁依赖的蚜虫、象虫和蛾幼虫的数量。这表明，蚂蚁参与的蚜虫并不总是对寄主植物有害的，但也有一些通过蚜虫间接的蚂蚁-植物互惠作用。2)研究了蚂蚁对栎树不同生活型蛾幼虫的影响。无遮挡的幼虫被蚂蚁显著减少，而栖息在中空的茎和茎与鳞片之间的小间隙的幼虫的密度不受蚂蚁的显著影响。似乎得到很好庇护的橡子钻孔虫，却被蚂蚁大量减少。橡子害虫通常需要不止一颗橡子才能完全生长，在橡子间漂移期间，它们似乎是蚂蚁的猎物。3)延龄草属、紫罗兰属和日本白刺草属的种子去除频率不受蚂蚁的控制，但它们的种子去除频率受蚂蚁的控制较小，因为地面甲虫会吞噬弹体，最终干扰蚂蚁对种子的传播。因此，不同于特殊的互惠关系，互惠互利的伙伴可能共同适应以避免外界的干扰，这些蚂蚁和植物处于松散的互惠关系中，蚂蚁不是专门的弹性体食者，几乎没有被诱导驱逐外来者。

Behavioral and morphological comparison was made between ant-attended aphid and its independent sibling ; however, no significant difference was detected. This is probably because the ant-concerned mutualisms are often, if not always, conditional or indirect. From this view point, therefore, some ant-concerned mutualisms were studied in the present study. Main results were : 1) On the ant-visited oak trees, ant-dependent aphids considerably enhanced their population. However, the ants reduced the number of ant-independent aphids, weevils and moth larvae which were harmful to the leaves and acorns of the tress. This suggests that the ant-attended aphids are not always harmful to their host plants but there are some indirect ant-plant mutualisms via aphids. 2) Ant effects on the different life forms of moth larvae were investigated on the oak trees. While unsheltered larvae were significantly depopulated by ants, the density of larvae inhabiting hollow stalks or small spaces between stalks and scales was not remarkably affected by ants. Acorn-borers, which were seemingly well sheltered, were considerably depopulated by ants. The acorn-borers often needed more than one acorn for their full growth, and they appeared to be hunted by ants during the inter-acorn drift. 3) Trillium tschonoskii, Viola spp.and Erythronium japonicum are myrmechochorous, but their seed removal frequencies were controlled less by ants than by ground beetles which devoured the elaiosomes and eventually interfered the seed dispersal by ants. Thus, unlike specialized mutualisms where mutualistic partners might co-adapt to avoid interference by outsiders, these ants and plants are in loose mutualism where the ants are not specialized elaiosome feeders and are hardly induced to expel the outsiders.