... Science Frontiers ONLINE No. 85: Jan-Feb 1993 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects Singing Caterpillars Actually, the singing caterpillars are not particularly tuneful. They really generate a vibration that is transmitted through the material they are resting on. You and I cannot hear caterpillar songs, but some ants can, and they are attracted to these insect sirens. The singing caterpillars belong to the Lycaenidae, which include such butterflies as the hairstreaks and blues. It is not only the singing or vibrating of this group of caterpillars that makes them remarkable, it is the complexity of their symbiotic relationships with several species of ants and a plant. Since both the ants and the caterpillars favor the Croton plant, they could well meet by chance ... seduce them with nectar that is much more nutritious and attractive than that produced by the Croton plant. Finally, they chemically force the ants into defensive postures against predatory wasps by spraying them with a mesmerizing substance from special "tentacle organs" near their heads. Why is all this subversive on the part of the caterpillars? It appears that the caterpillars have invaded and undermined the normal ant-plant symbiosis -- a very common, mutually beneficial arrangement. The ants have been seduced into letting the caterpillars feast on the Croton plant, although the ant-plant compact originally required that the ants repel all herbivorous insects. What makes this tale of subterfuge so remarkable is that the caterpillars had to evolve three separate organs in order to accomplish it: (1 ) their vibratory papillae; (2 ...