T11. 合作 (Cooperation)

鄭先祐 (Ayo) 教授國立台南大學 環境與生態學院

生態科學與技術學系 環境生態研究所 + 生態旅遊研究所

動物行為學 (通識 ) 國立臺南大學 通識課程 2011 年春

Ayo NUTN Web: http://myweb.nutn.edu.tw/~hycheng/

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Cooperation ( 合作 )

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合作行為的樣式Helping in the birthing process (fruit bat)Social grooming (primates)

合作行為的 Paths ( 途徑 )Path 1: reciprocity ( 相互的 )Path 2: byproduct mutualism ( 互利共生的

副產品 )Path 3: group selection ( 團體天擇 )Path 4: kin selection

Coalitions and alliances ( 聯合與同盟 )Interspecific mutualisms ( 物種間的互利 )

合作行為

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The word cooperation typically refers to an outcome from which two or more interacting individuals each receives a net benefit from their joint actions, despite the potential costs they may have to pay for undertaking such actions.

例如：jointly hunting groupTwo male guppies (lower left and lower

center of photo_ inspect a pike cichlid predator. Guppies cooperate during such risky endeavors.

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Two male guppies (lower left and lower center of photo_ inspect a pike cichlid predator. Guppies cooperate during such risky endeavors.

合作行為的樣式

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Helping in the birthing process 案例： Rodriques fruit bat

Unrelated female “ helpers” assist pregnant individuals in the birthing process.

During the birthing process, the helper continues providing assistance by grasping the wins of the pregnant females, thereby providing both protection and warmth, and subsequently cleaning newborn pups upon their emergence.

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(A) a nonpregnant female helper bat assumes the "feet down" birthing position as it "tutors" the pregnant female.(B) a pregnant female in a cradle position during birth is being groomed by a helper.(C) as the wing and foot of the pup emerge, the helper continues to groom the female that is giving birth.

Social grooming (allogrooming)

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Social grooming is “tension reduction” within primate group.

Primates are capable of exchanging one sort of resource– for example, social grooming – for another resource in what amounts to a “biological marketplace”.Numerous experiments in primates have

examined whether individuals cooperate with one another by exchanging social grooming for aid during aggressive interactions.

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合作行為的 Paths ( 途徑 )

Path 1: Reciprocity (Prisoner’s dilemma)

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If both suspects cooperate, they both receive a payoff of R (reward, 1 year in jail), and if they both defect, each one receives P (punishment, 3 years in jail).

If suspect 1 defects, but suspect 2 cooperates, the former receives a payoff of T (Temptation 誘惑 of cheat payoff, 0 years in jail), and the latter receives S (sucker’ 受騙者 payoff, 5 years in hail).T > R > P > S 0 > 1 > 3 > 5

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The prisoner’s dilemma game

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If a pair of individuals plays the prisoner’s dilemma game just once, then on the one play of the game, the only strategies possible are “cooperate” or “defect”.

In the iterated prisoner’s dilemma game, however, more complex rules, including “if-then” rules of the form “if the other individual does X, then I will do Y” can be employed – for example, “if she cooperates, I will cooperate; otherwise I will defect”.

Tit for tat (TFT) ( 一報還一報 ) = reciprocity-based strategy

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1. “niceness” –never the first to defect, cooperates as long as its partner cooperates.

3. To do what their partner did no the last move.

2. Swift “retaliation” –immediately defeats on a defecting partner since it copies its partner’s previous move and so, if its partner defects, it defects,

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Predator inspection and TFT in guppies

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Inspectors are more likely to get eaten the closer they approach a predator So it is more dangerous to be leading an inspection than lagging behind.Inspectors transfer the information that they receive during an inspection, so that any fish lagging behind would still receive the benefits associated with inspection.

Reciprocity and food sharing in vampire bats

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A typical group of vampire bats is composed largely of females, with a low average coefficient of relatedness (between 0.02 and 0.11).

Females in a nest of vampire bats regurgitate blood meals to other bats that have failed to obtain food in the recent past.

Ayo 2010 Ethology17Reciprocity and food sharing in vampire bats

Reciprocity and food sharing in vampire bats

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When examined which individuals were involved in food sharing, it was indeed the case that, despite the fact that the average relatedness in groups was low, genetic relatives were still more likely to swap blood meals than were other individuals.

Index of opportunity for reciprocity1. The probability of future interaction

between group members (TFT model)2. Blood meals provide a huge, potentially

life-saving benefit for recipients, while the cost of giving up some blood may not be as great to the donor.

3. Vampire bats are able to recognize one another

vampire bat blood meals

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(C) the genetic relatedness between recipients and all other roost members

(D) the actual relatedness between a recipient and a donor.

Bats were much more likely to regurgitate a meal to close kin and to those with whom they associated more often. Bats were capable of keeping track of who fed them in the past and who didn’t.

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(A) all possible association patterns that could be found between the recipient bat and others in the nest.(B) the actual association patterns found between donors and recipients.

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(C) the genetic relatedness between recipients and all other roost members(D) the actual relatedness between a recipient and a donor.

Bats were much more likely to regurgitate a meal to close kin and to those with whom they associated more often. Bats were capable of keeping track of who fed them in the past and who didn’t.

Neurobiological and endocrinological underpinnings of human reciprocity

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Neuroeconomics: a collaborative research effort between economists and neurobiologists who specialize in brain science.Experiments in neuroeconomics typically involve subjects who are making some economic decision.

儀器：fMRI (magnetic resonance imaging)PET (position emission tomography)

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Table 9.3 the monetary prisoner’s dilemma game, The payoff matrix for the game played by women who were either cooperating or cheating (defecting), in an economic cooperation experiment.

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(B) The fMRI scans showed that, when both subjects cooperated, brain areas associated with reward processing – OFC, rACC, the anterovetal striatum, and ACC)– were activated.

the trust game and punishment

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Two subjects played the trust game while one of them (player A) was hooked up to a PET scanner that monitored his brain activity.

The caudate nucleus, which is part of the dorsal striatum of the brain – depicted in yellow – was very active when player A punished player B for failing to return some of the money that A had provided to B.

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The level of oxytocin ( 催產素 ) was higher when subjects believed money was sent to them voluntarily (versus sent as a function of a random draw)

Path 2: byproduct mutualism

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An individual would incur an immediate cost or penalty if it did not act cooperativelySuch that the immediate net benefit of

cooperating would outweigh that of cheating.案例： byproduct mutualism.

Here, neither person gains by failing to move a stone that neither can budge alone.

案例： Blue jays

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The study of blue jay cooperationTo use Skinner boxes

byproduct mutualism and blue jays.Three pairs of blue jays were tested in a

three-stage experiment: Stage 1 = prisoner’s dilemma, Stage 2 = byproduct mutualism, and Stage 3= prisoner’s dilemma.

Jays cooperated when the payoff matrix matched byproduct mutualism, but not when it matched the prisoner’s dilemma.

案例： Blue jays

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A pair of blue jays, each of whom could peck one of two keys – a cooperate key or a defect key.

After the birds made their decisions, they were given a certain amount of food. The amount of food they obtained depended on what action they took, what action the other bird took, and which of two different payoff matrices the researchers had set up.P matrix: prisoner’s dilemma matrixM matrix: byproduct mutualism matrix

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prisoner’s dilemma matrix

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byproduct mutualism matrix

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M matrix

P matrix P matrix

案例： House sparrow food calls

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House sparrow produce a unique “chirrup” call when they come upon a food resource.

These calls appear to attract other birds to a newly discovered bounty, and as such chirrup calls may be regarded as some type of cooperation.

Chirrup call rates were higher when the food resource was divisible Chirrup call were associated with larger food

items– that is, those that were too big to remove from the experimental area.

Path 3: group selection

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Within-group selection Selection against cooperators and altruists.

Selfish types – those who do not cooperate– are always favored by within group selection

Between-group selectionFavors cooperation

案例： Group selection in ants

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Cooperative colony foundation has been well studied in the desert seed harvester ant, Messor pergandei.

Between-group selection: adult ants are very territorial, and “brood raiding” – wherein brood captured by ants from nearby colonies are raised within the victorious nests, and colonies that lose their brood in such interactions die.

Within groups, all co-founding queens in a nest assist in excavating their living quarters, and each produce approximately the same number of offspring.

Group selection in ants

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Until workers emerge, queens within a nest do not fight, and no dominance hierarchy exists.

from cooperation to aggressionCo-founding queens are cooperative

during worker production, with very little queen-queen aggression during this phase of colony development.

Once workers are produced- known as “ worker eclosion”, which is when they emerge from eggs, however, queen-queen aggression in nests escalates, as does the queen death rate,

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Coalitions ( 聯合 )

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Dyadic interactions, two individuals interact Polyadic interaction, interactions that involve

more than two individuals.One example of polyadic interactions involving

cooperation is coalition( 聯合 ) behavior, which is typically defined as a cooperative action taken by at least two other individuals or groups against another individual or group.

When coalitions exist for long periods of time, they are often referred to as alliances ( 同盟 ).

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(A) Three male dolphins swim together, forming a long-term coalition (or alliance)

(B) Pairs of male chimps often form coalitions to act against larger, more dominant, individuals.

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A male baboon (middle) involved in an aggressive interaction (with male on left) will often solicit ( 請求 ) others to aid him by turning his head in the direction of a potential coalition partner (male on right).

案例： Coalitions in baboons

案例： Alliances and “herding” behavior in cetaceans

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Bottlenose dolphins“first-order” alliances in dolphins are

composed of pairs or tros of males acting in a coordinated fashion to keep females by their side, presumably for the purpose of mating.

Different first-order alliances also join together in “second-order” superalliances and aggressively attach and steal females from other alliances.

The complex social interactions inherent in dolphin superalliances, may explain the evolution of large brain size in dolphins.

Interspecific mutualisms

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Ants and butterflies – mutualism with communication?

In numerous species of butterflies and ants, a mutualistic relationship has developed in which butterfly pupae and larvae produce a sugary secretion that ants readily consume, and ants protect the larvae from predators such as certain species of wasps and flies.

Ayo 2010 Ethology45Ants and butterflies

Imperial blue butterfly and ants

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The benefits to both parties in this mutualism are enormous.

Butterfly larvae are much less likely to survive when ants are experimentally removed from their environment.

Stridulating attracts antsMuted pupae, the experimenters applied nail polish to its stridulatiory organs.

Stridulating pupae attracted more ants than muted pupae.Stridulate 發尖銳的摩擦聲 ( 尤指昆蟲如蟋蟀所發 )

Ayo NUTN website:http://myweb.nutn.edu.tw/~hycheng/

問題與討論

Ayo 2011 動物行為學 ( 通識 )

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動物行為學 (通識 )

國立臺南大學 通識課程 2011 年春