Cheating, also known as exploitation, between organisms is a form of parasitism or specialized predation in which an organism engages in what appears to be a mutualistic relationship with another organism, but does not in fact provide any benefit to the other organism. The relationship between the organisms may be symbiotic, in which case cheating is a form of parasitism, or non-symbiotic, in which case cheating is a form of predation or herbivory.
Cheating is often found in situations where there are generalized non-specific mutualisms between broad classes of organisms, such as the relationship between flowering plants and animal pollinators or between mycorrhizal fungi and plants.
Some insects and birds engage in a behavior called nectar robbing in which they harvest nectar without pollinating the plant; nectar robbers are often close relatives or mimics of pollinating species. Another example would be myco-heterotrophic plants that take carbon from fungi in a shared mycorrhizal network without contributing anything to the fungal symbiont. These parasitic plants act as "mycorrhizal cheaters" in such systems.