Editing Behavioral ecology (section)

==Competing for resources==
The value of a social behavior depends in part on the social behavior of an animal's neighbors. For example, the more likely a rival male is to back down from a threat, the more value a male gets out of making the threat. The more likely, however, that a rival will attack if threatened, the less useful it is to threaten other males. When a population exhibits a number of interacting social behaviors such as this, it can evolve a stable pattern of behaviors known as an [[evolutionarily stable strategy]] (or ESS). This term, derived from economic [[game theory]], became prominent after [[John Maynard Smith]] (1982)<ref>[[John Maynard Smith|Maynard Smith, J.]] 1982. Evolution and the Theory of Games.</ref> recognized the possible application of the concept of a [[Nash equilibrium]] to model the evolution of behavioral strategies.

===Evolutionarily stable strategy===
In short, [[evolutionary game theory]] asserts that only [[Strategy (game theory)|strategies]] that, when common in the population, cannot be "invaded" by any alternative (mutant) strategy is an ESS, and thus maintained in the population. In other words, at equilibrium every player should play the best strategic response to each other. When the game is two player and symmetric, each player should play the strategy that provides the response best for it.

Therefore, the ESS is considered the evolutionary end point subsequent to the interactions. As the fitness conveyed by a strategy is influenced by what other individuals are doing (the relative frequency of each strategy in the population), behavior can be governed not only by optimality but the frequencies of strategies adopted by others and are therefore frequency dependent ([[Frequency dependent selection|frequency dependence]]).

Behavioral evolution is therefore influenced by both the physical environment and interactions between other individuals.

An example of how changes in geography can make a strategy susceptible to alternative strategies is the parasitization of the African honey bee, [[African bee|''A. m. scutellata'']].

===Resource defense===
The term economic defendability was first introduced by Jerram Brown in 1964. Economic defendability states that defense of a resource have costs, such as energy expenditure or risk of injury, as well as benefits of priority access to the resource. [[Territorial behavior]] arises when benefits are greater than the costs.<ref>{{cite journal|last=Brown|first=Jerram|title=The evolution of diversity in avian territorial systems|journal=[[The Wilson Bulletin]]|date=June 1964|volume=76|issue=2|pages=160–169|jstor=4159278}}</ref>

Studies of the [[golden-winged sunbird]] have validated the concept of economic defendability. Comparing the energetic costs a sunbird expends in a day to the extra nectar gained by defending a territory, researchers showed that birds only became territorial when they were making a net energetic profit.<ref>{{cite journal|last=Gill|first=Frank|author2=Larry Wolf|title=Economics of feeding territoriality in the golden-winged sunbird|journal=Ecology|year=1975|volume=56|issue=2|pages=333–345|jstor=1934964|doi=10.2307/1934964}}</ref> When resources are at low density, the gains from excluding others may not be sufficient to pay for the cost of territorial defense. In contrast, when resource availability is high, there may be so many intruders that the defender would have no time to make use of the resources made available by defense.

Sometimes the economics of resource competition favors shared defense. An example is the feeding territories of the [[white wagtail]]. The white wagtails feed on insects washed up by the river onto the bank, which acts as a renewing food supply. If any intruders harvested their territory then the prey would quickly become depleted, but sometimes territory owners tolerate a second bird, known as a satellite. The two sharers would then move out of phase with one another, resulting in decreased feeding rate but also increased defense, illustrating advantages of group living.<ref>{{cite journal|last=Davies|first=N. B.|author2=A. I. Houston|title=Owners and satellites: the economics of territory defence in the pied wagtail, ''Motacilla alba'' |journal=Journal of Animal Ecology|date=Feb 1981 |volume=50|issue=1|pages=157–180|doi=10.2307/4038|jstor=4038}}<!--|access-date=4 December 2012--></ref>

===Ideal free distribution===
{{Main|Ideal free distribution}}

One of the major models used to predict the distribution of competing individuals amongst resource patches is the ideal free distribution model. Within this model, resource patches can be of variable quality, and there is no limit to the number of individuals that can occupy and extract resources from a particular patch. Competition within a particular patch means that the benefit each individual receives from exploiting a patch decreases logarithmically with increasing number of competitors sharing that resource patch. The model predicts that individuals will initially flock to higher-quality patches until the costs of crowding bring the benefits of exploiting them in line with the benefits of being the only individual on the lesser-quality resource patch. After this point has been reached, individuals will alternate between exploiting the higher-quality patches and the lower-quality patches in such a way that the average benefit for all individuals in both patches is the same. This model is ''ideal'' in that individuals have complete information about the quality of a resource patch and the number of individuals currently exploiting it, and ''free'' in that individuals are freely able to choose which resource patch to exploit.<ref>{{cite book|last=Fretwell|first=Stephen D.|title=Population in a Seasonal Environment |url=https://archive.org/details/populationsinsea0000fret|url-access=registration|year=1972|publisher=Princeton University Press|location=Princeton, NJ}}</ref>

An experiment by Manfred Malinski in 1979 demonstrated that feeding behavior in [[three-spined stickleback]]s follows an ideal free distribution. Six fish were placed in a tank, and food items were dropped into opposite ends of the tank at different rates. The rate of food deposition at one end was set at twice that of the other end, and the fish distributed themselves with four individuals at the faster-depositing end and two individuals at the slower-depositing end. In this way, the average feeding rate was the same for all of the fish in the tank.<ref>{{cite journal |last=Milinski |first=Manfred |title=An Evolutionarily Stable Feeding Strategy in Sticklebacks |journal=Zeitschrift für Tierpsychologie |date=1979 |volume=51 |issue=1 |pages=36–40 |doi=10.1111/j.1439-0310.1979.tb00669.x}}</ref>

===Mating strategies and tactics===
As with any [[competition]] of resources, species across the animal kingdom may also engage in competitions for mating.  If one considers mates or potentials mates as a resource, these sexual partners can be randomly distributed amongst resource pools within a given environment.  Following the ideal free distribution model, suitors distribute themselves amongst the potential mates in an effort to maximize their chances or the number of potential matings.  For all competitors, males of a species in most cases, there are variations in both the strategies and tactics used to obtain matings.  Strategies generally refer to the genetically determined behaviors that can be described as [[causality|conditional]].  Tactics refer to the subset of behaviors within a given genetic strategy.  Thus it is not difficult for a great many variations in mating strategies to exist in a given environment or species.<ref>{{cite journal |last=Dominey |first=Wallace |title=Alternative Mating Tactics and Evolutionarily Stable Strategies |journal=American Zoology |year=1984 |volume=24|issue=2|pages=385–396|doi=10.1093/icb/24.2.385|doi-access=free }}</ref>

An experiment conducted by Anthony Arak, where playback of synthetic calls from male [[natterjack toad]]s was used to manipulate behavior of the males in a chorus, the difference between strategies and tactics is clear. While small and immature, male natterjack toads adopted a satellite tactic to parasitize larger males. Though large males on average still retained greater reproductive success, smaller males were able to intercept matings. When the large males of the chorus were removed, smaller males adopted a calling behavior, no longer competing against the loud calls of larger males.  When smaller males got larger, and their calls more competitive, then they started calling and competing directly for mates.<ref>{{cite journal|last=Arak|first=Anthony|title=Sexual selection by male–male competition in natterjack toad choruses |journal=Nature |year=1983 |volume=306 |issue=5940 |doi=10.1038/306261a0 |pages=261–262 |bibcode = 1983Natur.306..261A |s2cid=4363873}}</ref>