Cheating (biology)
Encyclopedia
Cheating is a metaphor commonly used in behavioral ecology to describe organisms that receive a benefit at the cost of others. Cheating is common in many mutualistic and altruistic
Altruism in animals
Altruism is a well-documented animal behaviour, which appears most obviously in kin relationships but may also be evident amongst wider social groups, in which an animal sacrifices its own well-being for the benefit of another animal.- Overview :...

 relationships. Natural selection favors cheating, but there are mechanisms to regulate cheating.

Theoretical Models

The producer
Autotroph
An autotroph, or producer, is an organism that produces complex organic compounds from simple inorganic molecules using energy from light or inorganic chemical reactions . They are the producers in a food chain, such as plants on land or algae in water...

/scrounger game contains cheaters. Producers search for their own food while scroungers take the food others have found. Producers benefit when scroungers are common. Scroungers benefit when scroungers are rare. If there are many scroungers and few producers, the producers are easily able to find food since there is much less competition. If there are few scroungers and many producers, the scroungers can easily cheat. The scroungers are no longer competing against each other to take the producer’s food. A bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...

 can be a scrounger. Instead of foraging
Foraging
- Definitions and significance of foraging behavior :Foraging is the act of searching for and exploiting food resources. It affects an animal's fitness because it plays an important role in an animal's ability to survive and reproduce...

 for its own food, the scrounger will wait until another bird comes back with food. The next day, the scrounger will follow the successful bird to the patch. The cheating bird reaps the benefits without putting in the effort that the producer put in to find the food.

Animal Examples

Some examples of animals that are known to cheat include: cleaner fish
Cleaner fish
Cleaner fish are fish that provide a service to other fish species by removing dead skin and ectoparasites. This is an example of mutualism, an ecological interaction that benefits both parties involved. A wide variety of fishes have been observed to display cleaning behaviors including wrasses,...

, social insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...

s, ungulate
Ungulate
Ungulates are several groups of mammals, most of which use the tips of their toes, usually hoofed, to sustain their whole body weight while moving. They make up several orders of mammals, of which six to eight survive...

s, and bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...

s. Cleaner fish have a mutualistic relationship with their clients. The cleaners eat ectoparasites off their clients. The clients benefit from being cleaned, and the cleaners benefit from acquiring food. However, some cleaners cheat by eating tissue, scales, and mucus off their clients instead of only ectoparasites. This could be detrimental to the clients and possibly turn the mutualistic relationship into commensalism
Commensalism
In ecology, commensalism is a class of relationship between two organisms where one organism benefits but the other is neutral...

 or parasitism
Parasitism
Parasitism is a type of symbiotic relationship between organisms of different species where one organism, the parasite, benefits at the expense of the other, the host. Traditionally parasite referred to organisms with lifestages that needed more than one host . These are now called macroparasites...

.


As for social insects, such as bee
Bee
Bees are flying insects closely related to wasps and ants, and are known for their role in pollination and for producing honey and beeswax. Bees are a monophyletic lineage within the superfamily Apoidea, presently classified by the unranked taxon name Anthophila...

s, ant
Ant
Ants are social insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from wasp-like ancestors in the mid-Cretaceous period between 110 and 130 million years ago and diversified after the rise of flowering plants. More than...

s, and wasp
Wasp
The term wasp is typically defined as any insect of the order Hymenoptera and suborder Apocrita that is neither a bee nor an ant. Almost every pest insect species has at least one wasp species that preys upon it or parasitizes it, making wasps critically important in natural control of their...

s, the queen
Eusociality
Eusociality is a term used for the highest level of social organization in a hierarchical classification....

 is the only individual that is supposed to reproduce. In some cases, cheating workers reproduce also. This disrupts the altruistic relationship between the queen and the workers.


Vigilance
Alertness
Alertness is the state of paying close and continuous attention, being watchful and prompt to meet danger or emergency, or being quick to perceive and act. It is related to psychology as well as to physiology...

 is essential for many colonial
Colony
In politics and history, a colony is a territory under the immediate political control of a state. For colonies in antiquity, city-states would often found their own colonies. Some colonies were historically countries, while others were territories without definite statehood from their inception....

 animals. The animals on the outside of the group will be vigilant, while those on the inside forage
Forage
Forage is plant material eaten by grazing livestock.Historically the term forage has meant only plants eaten by the animals directly as pasture, crop residue, or immature cereal crops, but it is also used more loosely to include similar plants cut for fodder and carried to the animals, especially...

. The animals within the group also monitor each other’s vigilance. A cheater may emerge in groups with vigilant animals. The cheater might try to forage the entire time, while the rest of the group switches between foraging and being vigilant.

Non-animal Examples

The relationships between flowering plants and their animal pollinator
Pollinator
A pollinator is the biotic agent that moves pollen from the male anthers of a flower to the female stigma of a flower to accomplish fertilization or syngamy of the female gamete in the ovule of the flower by the male gamete from the pollen grain...

s and plants and fungi are generally mutualistic, but there are cheaters. Two species of yucca moths eat yucca
Yucca
Yucca is a genus of perennial shrubs and trees in the family Asparagaceae, subfamily Agavoideae. Its 40-50 species are notable for their rosettes of evergreen, tough, sword-shaped leaves and large terminal panicles of white or whitish flowers. They are native to the hot and dry parts of North...

 seeds, but do not pollinate the yucca because they lack the necessary mouthparts. The animal pollinators are not the only cheaters though. Some flowers do not produce nectar. Many pollinators are not able to distinguish between which flowers produce nectar and which do not; therefore, some flowers cheat by not making nectar for the pollinator. Examples of nectarless plants include some species of orchids. Orchids are not just cheaters towards pollinators. Some orchids cheat by not providing fixed carbon
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...

 to mutualistic fungi.

Solutions

There are ways to avoid cheaters, including: wikt:policing, changing partners, and pushing the cheater on the outside of a vigilant group. In order to avoid cheating in polyandrous honeybees, worker policing is enforced, which entails the removal of egg
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...

s laid by selfish workers. To prevent cheating cleaner fish, the clients chase them or switch partners. Furthermore, in order to prevent a cheater emerging in a vigilant group, the group members will force the cheater on the outside, where he/she has to be vigilant. The group members may also physically beat the cheater. If the cheater does not conform, he/she will be kicked out.
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