Effects of Ants on the Guild Structure of Herbivorous Beetles

1.在日本金泽县的一个丘陵地区，研究了五种丰富的甲虫共生现象，这些甲虫是以蓟叶为食的。所研究的种类为：一种食草性瓢虫Epilachna niponica(Epiachninae)和4种金蝶科昆虫Dactylispa Masoni(Hispinae)、Cassida rubiginosa(Cassidinae)、Altica Cirsicola(Alticinae)和Lema Cirsicola(Criocerinae)。分别对蓟枝条及其叶片进行标记，以记录(1)蓟类食草动物的生长和危害情况，(2)成虫、卵、幼虫和蛹的位置和数量。对成虫的季节发生、空间分布、成虫寿命和扩散、幼龄期死亡率等进行量化，比较物种间的资源利用格局。这些甲虫没有表现出产卵地点的分离：在一片蓟叶上经常发现不同种类的一个以上的卵块。蓟上寄生着两种严重的蚜虫。蓟上的蚂蚁密度很低，蚂蚁不参加麦长管蚜。在实验室条件下，进行了存活、生育时间表和食物选择的实验。

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.