A new study of the parasite(寄生)-host relationship of Alcon blue caterpillars and the ants that feed them describes how the Alcon blue's larval (幼虫の)odors mimic those of the ants' own young. When the caterpillars are able, they leave the plants on which they began their development and wait on the ground for the ants to discover them. The ants bring the caterpillars back to their nests and feed them, often in preference to the ants' own brood(幼虫). There, the caterpillar becomes a highly virulent(悪性の、有毒な、悪意に満ちた)parasite, eating both the food brought by worker ants and some of the ant brood itself. Caterpillars that more accurately mimic the brood's odors are picked up and brought to the ant nest sooner.