:Contest competition

In ecology, contest competition refers to a situation where available resources, such as food and mates, are utilized only by one or a few individuals, thus preventing development or reproduction of other individuals. It refers to a hypothetical situation in which several individuals stage a contest for which one eventually emerges victorious. Contest competition is the opposite of scramble competition, a situation in which available resources are shared equally among individuals.

As contest competition allows the monopolization of resources, offspring will typically always be produced and survive until adulthood independent of the population size, resulting in stable population dynamics. This is in stark contrast to scramble competition which can result in periodic or chaotic population dynamics. The Beverton–Holt model is often used to represent population dynamics arising from contest competition. This model, and a few other well-known population models, can be explicitly derived from individual-level processes assuming contest competition and a random distribution of individuals among resources.{{cite journal | vauthors = Brännström Å, Sumpter DJ | title = The role of competition and clustering in population dynamics. | journal = Proceedings of the Royal Society B: Biological Sciences | date = October 2005 | volume = 272 | issue = 1576 | pages = 2065–72 | doi = 10.1098/rspb.2005.3185 | pmid = 16191618 | url = http://www.math.uu.se/~david/web/BrannstromSumpter05a.pdf | pmc = 1559893 }}

Contest competition has been observed in a variety of species. In white-faced monkeys, Cebus capucinus, regardless of aggression, avoidance, or sex, higher ranking monkeys had higher energy intake within their group.{{Cite journal| vauthors = Vogel ER |date=August 2005|title=Rank differences in energy intake rates in white-faced capuchin monkeys, Cebus capucinus: the effects of contest competition |journal=Behavioral Ecology and Sociobiology|language=en|volume=58|issue=4|pages=333–344|doi=10.1007/s00265-005-0960-4|bibcode=2005BEcoS..58..333V |s2cid=29039152|issn=0340-5443}} For female Microcebus murinus groups, if the resource (fruit) could be monopolized, they would compete within their group for it.{{cite journal | vauthors = Dammhahn M, Kappeler PM | title = Scramble or contest competition over food in solitarily foraging mouse lemurs (Microcebus spp.): New insights from stable isotopes | journal = American Journal of Physical Anthropology | volume = 141 | issue = 2 | pages = 181–9 | date = February 2010 | pmid = 19591211 | doi = 10.1002/ajpa.21129 }} In a controlled lab experiment with three parasitic wasp species (Dinarmus basalis, Anisopteromalus calandrae, and Heterospilus prosopidis) they found that between the first larvae in the host and the second, the larvae that would win depended on the time between them.{{Cite journal| vauthors = Wai KM, Fujii K |date=June 1990|title=Intraspecific larval competition among wasps parasitic of bean weevil larvae |journal=Researches on Population Ecology|language=en|volume=32|issue=1|pages=85–98|doi=10.1007/BF02512591|bibcode=1990PopEc..32...85W |s2cid=41202920|issn=0034-5466}} There was also a Nicholson–Bailey model made to partially explain the relationship between Heterospilus prosopidis and its host Callosobruchus maculatus.{{Cite journal| vauthors = Tuda M, Iwasa Y |date=October 1998|title=Evolution of contest competition and its effect on host–parasitoid dynamics |journal=Evolutionary Ecology|language=en|volume=12|issue=7|pages=855–870|doi=10.1023/A:1006550817371|bibcode=1998EvEco..12..855T |s2cid=20737569|issn=0269-7653}}

Fitness gains for the winner of the contest is not always known. For example, in mountain gorillas, Gorilla beringei, higher ranking females had higher average food-site resident times and higher aggression and avoidance while eating than lower ranking females.{{Cite journal| vauthors = Grueter CC, Robbins AM, Abavandimwe D, Vecellio V, Ndagijimana F, Ortmann S, Stoinski TS, Robbins MM | display-authors = 6 |date=2016|title=Causes, mechanisms, and consequences of contest competition among female mountain gorillas in Rwanda |journal=Behavioral Ecology|language=en|volume=27|issue=3|pages=766–776|doi=10.1093/beheco/arv212|issn=1045-2249|doi-access=free}} Higher ranking females have higher reproductive success, but both energy intake and the energy needed for travel to the food site do not differ among ranks.

Other research in contest competition focus on what aspects are relevant for contest resolution. In a study looking at aerial wars of attrition in territorial insects, they found that the energy Cuterebra austeni got from their resources before adulthood played a role in who won.{{cite journal | vauthors = Kemp DJ, Alcock J | title = Lifetime resource utilization, flight physiology, and the evolution of contest competition in territorial insects | journal = The American Naturalist | volume = 162 | issue = 3 | pages = 290–301 | date = September 2003 | pmid = 12970838 | doi = 10.1086/376890 | bibcode = 2003ANat..162..290K | s2cid = 25146159 }} Some species have obvious gains when they win, but no morphological and/or physiological tell to determine who would win. This is the case with several species of butterflies where males hold a contest over territory.{{Cite journal| vauthors = Kemp DJ, Wiklund C |date=2001-05-07|title=Fighting without weaponry: a review of male-male contest competition in butterflies |journal=Behavioral Ecology and Sociobiology|volume=49|issue=6|pages=429–442|doi=10.1007/s002650100318|bibcode=2001BEcoS..49..429K |s2cid=25209886|issn=0340-5443}} However, a study in 2010 that staged contests between male Pararge aegeria found motivation to be a factor.{{cite journal | vauthors = Bergman M, Olofsson M, Wiklund C | title = Contest outcome in a territorial butterfly: the role of motivation | journal = Proceedings. Biological Sciences | volume = 277 | issue = 1696 | pages = 3027–33 | date = October 2010 | pmid = 20462910 | pmc = 2982028 | doi = 10.1098/rspb.2010.0646 }} The more time a male spent with a female, the more persistent they were, which increased the likelihood of the male to win the contest over the previous male holding dominance over the territory.