cheater

In biology, a "cheater" refers to an organism that exploits an existing mutualistic relationship without reciprocating benefits. This can involve stealing resources or mimicking a beneficial species to gain an advantage. For example, some bees pierce flowers to steal nectar, bypassing the specialized pollinators. Similarly, some fish mimic cleaner fish but instead bite their hosts.1

This concept is distinct from "kin selection," a theory where altruistic behavior is favored if it increases the survival and reproduction of related individuals who share genes. While cheating exploits others for individual gain, kin selection explains how self-sacrificing actions can benefit an organism's genes by helping relatives.23