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=== In eusocial animals ===
The suppression of reproduction by dominant individuals is the most common mechanism that maintains the hierarchy. In [[eusocial mammals]] this is mainly achieved by aggressive interactions between the potential reproductive females. In eusocial insects, aggressive interactions are common determinants of reproductive status, such as in the [[bumblebee]] ''[[Bombus bifarius]]'',<ref>{{cite journal |last1=Foster |first1=R. L. |last2=Ameilia |first2=B. |last3=Verdirame |first3=D. |last4=O'Donnell |first4=S. |year=2004 |title=Reproductive physiology, dominance interactions, and division of labour among bumble bee workers |journal=Physiological Entomology |volume=29 |issue=4 |pages=327–334 |doi=10.1111/j.0307-6962.2004.00388.x |s2cid=34826563 }}</ref> the [[paper wasp]] ''[[Polistes annularis]]''<ref>{{cite journal |last1=Hughes |first1=C. R. |last2=Beck |first2=M. O. |last3=Strassman |first3=J. E. |year=1987 |title=Queen succession in the social wasp Polistes annularis |journal=Ethology |volume=76 |issue=2 |pages=124–132 |doi=10.1111/j.1439-0310.1987.tb00678.x|bibcode=1987Ethol..76..124H }}</ref> and in the ants ''[[Dinoponera australis]]'' and ''[[Dinoponera quadriceps|D. quadriceps]]''.<ref>{{cite journal |last1=Monnin |first1=T. |last2=Ratnieks |first2=F. L. W. |last3=Brandao |first3=C. R. F. |s2cid=11142025 |year=2003 |title=Reproductive conflict in animal societies: hierarchy length increases with colony size in queenless ponerine ants |journal=Behavioral Ecology and Sociobiology |volume=54 |pages=71–79 |doi=10.1007/s00265-003-0600-9}}</ref> In general, aggressive interactions are ritualistic and involve antennation (drumming), abdomen curling and very rarely mandible bouts and stinging. The winner of the interaction may walk over the subordinated, that in turn assumes a prostrated posture. To be effective, these regulatory mechanisms must include traits that make an individual rank position readily recognizable by its nestmates. The composition of the [[lipid]] layer on the [[Insect cuticle|cuticle]] of social insects is the clue used by nestmates to recognize each other in the colony, and to discover each insect's reproductive status (and rank).<ref>{{cite journal |last=Monnin |first=T. |year=2006 |title=Chemical recognition of reproductive status in social insects |journal=Annales Zoologici Fennici |volume=43 |pages=515–530 }}</ref> Visual cues may also transmit the same information. Paper wasps ''[[Polistes dominulus]]'' have individual "facial badges" that permit them to recognize each other and to identify the status of each individual. Individuals whose badges were modified by painting were aggressively treated by their nestmates; this makes advertising a false ranking status costly, and may help to suppress such advertising.<ref name="Tibbetts 2004">{{cite journal |doi=10.1038/nature02949 |last1=Tibbetts |first1=E. A. |last2=Dale |first2=J. |s2cid=4428070 |year=2004 |title=A socially enforced signal of quality in paper wasp |journal=Nature |volume=432 |issue=7014 |pages=218–222 |pmid=15538369 |bibcode=2004Natur.432..218T }}</ref>
Other behaviors are involved in maintaining reproductive status in social insects. The removal of a thoracic [[sclerite]] in ''[[Diacamma]]'' ants inhibits ovary development; the only reproductive individual of this naturally queenless genus is the one that retains its sclerite intact. This individual is called a [[gamergate (ant)|gamergate]], and is responsible for mutilating all the newly emerged females, to maintain its social status. Gamergates of ''[[Harpegnathos saltator]]'' arise from aggressive interactions, forming a hierarchy of potential reproductives.<ref>{{cite journal |last1=Peeters |first1=C. |last2=Liebig |first2=J. |last3=Hölldobler |first3=B. |year=2000 |title=Sexual reproduction by both queens and workers in the ponerine ant Harpegnathos saltator |journal=Insectes Sociaux |volume=47 |issue=4 |pages=325–332 |doi=10.1007/pl00001724 |s2cid=8728206 }}</ref>
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The social insects mentioned above, excluding termites, are [[haplodiploid]]. Queen and workers are diploid, but males develop from haploid genotypes. In some species, suppression of [[ovary]] development is not totally achieved in the worker caste, which opens the possibility of reproduction by workers. Since [[nuptial flights]] are seasonal and workers are wingless, workers are almost always non-breeders, and (as [[gamergate (ant)|gamergate]] ants or [[laying worker bee]]s) can only lay unfertilised eggs. These eggs are in general viable, developing into males. A worker that performs reproduction is considered a "cheater" within the colony, because it leaves disproportionately more descendants than do its sisters and mother. The advantage of remaining functionally sterile is only accomplished if every worker assume this "compromise". When one or more workers start reproducing, the "social contract" is destroyed and the colony cohesion is dissolved. Aggressive behavior derived from this conflict may result in the formation of hierarchies, and attempts of reproduction by workers are actively suppressed. In some wasps, such as ''[[Polistes fuscatus]]'', instead of not laying eggs, the female workers begin being able to reproduce, but once being under the presence of dominant females, the subordinate female workers can no longer reproduce.<ref name="Social Biology">{{cite journal |last1=West-Eberhard |first1=M. J. |year=1969 |title=The social biology of polistine wasps |journal=Mis. Publ. Zool. Univ. Michigan |volume=140 |pages=1–101}}</ref>
In some wasp species such as [[Liostenogaster flavolineata]] there are many possible queens that inhabit a nest, but only one can be queen at a time. When a queen dies the next queen is selected by an age-based dominance hierarchy. This is also true in the species ''[[Polistes instabilis]]'', where the next queen is selected based on age rather than size. ''[[Polistes exclamans]]'' also exhibits this type of hierarchy.<ref name="Gerontocracy">{{Cite journal |author=Strassmann & Meyer |s2cid=54398769 |year=1983 |title=Gerontocracy in the social wasp, ''Polistes exclamans'' |journal=[[Animal Behaviour (journal)|Animal Behaviour]] |volume=31 |issue=1 |pages=431–438 |doi=10.1016/S0003-3472(83)80063-3}}</ref> Within the dominance hierarchies of the ''[[Polistes versicolor]]'', however, the dominant-subordinate context in the yellow paper wasps is directly related to the exchange of food. Future foundresses within the nest compete over the shared resources of nourishment, such as protein. Unequal nourishment is often what leads to the size differences that result in dominant-subordinate position rankings. Therefore, if during the winter aggregate, the female is able to obtain greater access to food, the female could thus reach a dominant position.<ref>{{cite journal |last1=González |first1=J. A. |last2=Nascimento |first2=F. S. |last3=Gayubo |first3=S. F. |year=2002 |title=Observations on the Winter Aggregates of Two Polistine Paper Wasps (Hymenoptera Vespidae Polistinae) |journal=Tropical Zoology |volume=15 |issue=1 |pages=1–4 |doi=10.1080/03946975.2002.10531162 |doi-access=free|bibcode=2002TrZoo..15....1G }}</ref>
In some species, especially in ants, more than one queen can be found in the same colony, a condition called [[Polygyny in animals|polygyny]]. In this case, another advantage of maintaining a hierarchy is to prolong the colony lifespan. The top ranked individuals may die or lose fertility and "extra queens" may benefit from starting a colony in the same site or nest. This advantage is critical in some ecological contexts, such as in situations where nesting sites are limited or dispersal of individuals is risky due to high rates of predation. This polygynous behavior has also been observed in some eusocial bees such as ''[[Schwarziana quadripunctata]]''. In this species, multiple queens of varying sizes are present. The larger, [[physogastric]], queens typically control the nest, though a "dwarf" queen will take its place in the case of a premature death.<ref name="nogueira09">{{cite journal |last1=Nogueira-Ferreira |first1=F. H. |last2=Silva-Matos |first2=E. V. |last3=Zucchi |first3=R. |year=2009 |title=Interaction and Behavior of Virgin and Physogastric Queens in Three Meliponini Species (Hymenoptera, Apidae) |url=https://www.researchgate.net/publication/26319081 |journal=Genetics and Molecular Research |volume=8 |issue=2 |pages=703–708 |doi=10.4238/vol8-2kerr008 |pmid=19554769 |doi-access=free}}</ref>
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