昆虫幼虫对凤尾蕨属植物孢子囊群的拟态

Soral crypsis of insect larvea on bracken ferns

蕨类植物和昆虫共同进化了三亿多年,但是两者的协同进化一直很少得到关注。对湖南省桑植县的凤尾蕨属植物上的昆虫幼虫进行调查,结果表明42棵4种凤尾蕨属植株上有夜蛾科幼虫89条,叶蜂科幼虫21条。叶蜂科幼虫通过形态和体色拟态凤尾蕨属植物的孢子囊群盖,取食凤尾蕨属植物的叶片;而夜蛾科幼虫隐藏在凤尾蕨属植物成熟的囊群盖中取食孢子,幼时乳白色,成熟时转变为淡黄色,有些会出现褐色斑点,同样与凤尾蕨属的孢子囊群盖具有拟态现象。进一步的调查还在凤尾蕨植物上发现猎食性的跳蛛,同时在其体表发现携带的孢子。首次在凤尾蕨属植物上发现拟态昆虫幼虫、特别是寄生性昆虫及其天敌跳蛛的发现,对研究蕨类植物、昆虫幼虫及其天敌之间存在的食物链关系和协同进化现象具有重要意义。

Ferns and insects live on the earth together more than 300 million years, but the interaction is rare known. A field surveys was hold in Sangzhi County of Hunan province about the insect larvae on Pteris spp. We found 89 Noctuidae larvae and 21 Tenthredinidae larvae on 42 bracken ferns belong to four species. The larvea of Tenthredinidae mimiced the indusium through appearance and color, and feeded on immature leaves. By contrast, the larvea of Noctuidae feeded on spores hiding under the indusium, whose color turns white to buff, with brown spot sometime, as another kind of soral crypsis. Meanwhile, a jump spider of prey was observed, which may be attracted by the larvea. The spider acts on the mature sporophyl, carrying several spores. These discoveries give us a good insight into the interaction and co-evolution among ferns, insect larvea and spider.