Effects of Ants on the Guild Structure of Herbivorous Beetles

1. 在日本金泽的一个丘陵地区，研究了以蓟叶为食的五种丰富的甲虫之间的共生现象。研究种为：草食性瓢虫nipepilachna （Epilachninae）和4种黄花瓢虫Dactylispa masoni （Hispinae）、Cassida rubiginosa （Cassidinae）、Altica cirsicola （Alticinae）和Lema cirsicola （Criocerinae）。分别对蓟枝和叶片进行了标记，记录了(1)蓟的生长和受草食动物的危害情况；(2)5种蓟的成虫、卵、幼虫和蛹的位置和数量。定量分析了成虫的季节发生、空间分布、寿命和分布、幼期死亡率，比较了不同种间的资源利用模式。这些甲虫没有显示出产卵地点的分离：在一片蓟叶上经常发现不止一个不同种类的卵团在一起。这些蓟受到两种蚜虫的严重侵害。蓟上的蚂蚁密度很低，蚂蚁对蚜虫不感兴趣。在实验室条件下，进行了成活率、生育力时间表和食物选择试验。

1. Co-occurrence among five abundant species of beetles that feed the leaves of thistle Cirsium matsumurae was examined in a hilly region of Kanazawa, Japan. The studied species were : a herbivorous ladybird Epilachna niponica (Epilachninae) and four chrysomerid species Dactylispa masoni (Hispinae), Cassida rubiginosa (Cassidinae), Altica cirsicola (Alticinae) and Lema cirsicola (Criocerinae).2. Thistle shoots and their leaves were individually tagged to record (1) the growth and damage by the herbivores of the thistle, and (2) the position and number of adults, eggs, larvae and pupae of the five species. Seasonal occurrence, spatial distribution, longevity and dispersal of adults, and mortality rates in immature stages are quantified to compare the resource utilization patterns among the species.3. These beetles did not show the segregation of oviposition sites : more than one egg mass of different species was frequently found together on one thistle leaf.4. The thistles were seriously infested with two species of aphids. Ant density on the thistles was very low and ant did not attend the aphids.5. Under laboratory conditions, experiments for survivorship and fertility schedules and food selection were carried out.