Fordyce James A
Section of Evolution and Ecology, Center for Population Biology, University of California, Davis, CA 95616, USA.
Oecologia. 2003 Apr;135(2):250-7. doi: 10.1007/s00442-003-1177-8. Epub 2003 Jan 25.
Many hypotheses have been proposed to explain the adaptive significance of aggregative feeding in the Lepidoptera. One hypothesis that has received little attention is how induced plant responses may be influenced by aggregative feeding, as compared to feeding by solitary larvae. This study investigated the role of aggregative feeding of the pipevine swallowtail, Battus philenor, in California with special emphasis on the induced responses to herbivory of its hostplant. Here, I show that first-instar larvae develop faster when feeding in a large aggregation compared to solitary or small groups of larvae. Furthermore, I show that this effect is mediated by a larval-density-dependent response in the plant and is independent of prior larval experience and direct interaction among larvae. These results indicate that large groups of larvae can effectively enhance hostplant suitability. A separate experiment showed that larvae feeding on previously damaged leaves had a reduced growth rate. Thus, following initial damage a plant first goes through a period of increased suitability, followed by induced resistance against subsequent herbivory. Aggregative feeding in this system may be an adaptive strategy for larvae to manipulate hostplant suitability, adding a new dimension to the role of aggregative feeding for the Lepidoptera.
人们已经提出了许多假说，以解释鳞翅目昆虫群体取食的适应性意义。一个很少受到关注的假说是，与单独取食的幼虫相比，群体取食如何影响植物的诱导反应。本研究调查了加利福尼亚州西番莲燕尾蝶（Battus philenor）群体取食的作用，特别强调了其寄主植物对食草作用的诱导反应。在这里，我表明，与单独或小群体取食的幼虫相比，一龄幼虫在大群体中取食时发育得更快。此外，我表明，这种效应是由植物中幼虫密度依赖性反应介导的，并且与幼虫先前的经历以及幼虫之间的直接相互作用无关。这些结果表明，大量幼虫可以有效地提高寄主植物的适宜性。另一个实验表明，取食先前受损叶片的幼虫生长速度降低。因此，在最初受到损害后，植物首先会经历一段适宜性增加的时期，随后会对随后的食草作用产生诱导抗性。在这个系统中，群体取食可能是幼虫操纵寄主植物适宜性的一种适应性策略，为鳞翅目昆虫群体取食的作用增添了一个新的维度。
