Be they protists, worms, or vertebrates, parasites depend on their ability to deceive. The nest parasites, like the cowbird and cuckoo, mimic the offspring of their host birds. Their eggs often look like the eggs of a host bird (at least within the visual world of the host), and when they hatch they imitate the hunger calls of the baby host birds. Some can imitate the calls of a nest full of hungry chicks. Although their eggs and offspring are usually larger than their host, the adoptive parents don’t care. In fact, birds favor large offspring because it signals health. The parasite takes advantage of the inability of the host to overcome their preference for large healthy babies. When an animal gives the same response to a stimulus and can’t vary it, we call the stimulus-response behavior “fixed,” and we call it a Fixed Action Pattern.
The Wisdom of Loki, by Ptera Hunter, explores patterns of deceit in the natural world, including predator-prey, parasitic, and molecular deceits.