05 親緣關係 ( Kinship) 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

05 親緣關係 (Kinship)

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/

Ayo 2011 動物行為學 ( 通識 )

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親緣關係 (Kinship)親緣關係與動物行為親緣理論

Relatedness and inclusive fitnessFamily dynamics

家庭的衝突Parent-offspring conflictSibling rivalry

親緣辨識Matching modelsRule-of-thumb models of kin

recognition


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親緣關係與動物行為Belding’s ground squirrels give alarm calls

when a predator is spotted.Alarm calls are most often emitted by females

Females are surrounded by relatives, while adult males are generally in groups that do not contain their genetic relatives

Belding’s ground squirrel groups are typically made up of mothers, daughters, and sisters who cooperate with one another in a variety of contexts.

Males that emigrate into such groups cooperate to a much smaller degree.


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In Belding’s ground squirrels, females (A) are much more likely than males to emit alarm calls when predators are sighted. Such alarm calls warn others, including female relatives and their pups (B)


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Homicide( 殺人 ) in humans

512 homicide cases occurring 1972 in Detroit, Michigan

127 (25%) of these murders were committed denote as “relatives”.However, the police classify in-laws, and

even boyfriend-girlfriend pairs, as relatives, rather than limiting this category to genetic kin.

Only 6% of the murders involved relatives.倘若按相處時間計算其風險， (Table 8.1)


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Genetic relatives rarely kill each other


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親緣理論The modern study of animal behavior and

evolution began in the early 1960s, when W. D. Hamilton, one of the leading evolutionary biologists of the twentieth century, published his now famous papers on genetic kinship and the evolution of social behavior.

These papers formalized the theory of “inclusive fitness” or “kinship” theory and revolutionized the way scientists understood evolution and ethology.


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A classic case of helping genetic relatives is that of mothers feeding their young. In bank swallows, young chicks remain at the nest, and mothers remember the location of their nests so that they can return after foraging to feed youngsters there


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Relatedness and inclusive fitness

r = genetic relatedness Inclusive fitness = direct + indirect

fitness Hamilton’s rule

( ∑ r b) - c > 0b = the benefit c = the cost accrued to the individual expressing the trait


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The effects of helping kin Using groups of gray-crowned bablers

that ranged from an initial size of six to eight individuals, Brown and his colleagues removed all but one of the nonreproductive helpers from the experimental groups, while leaving the number of nonreproductive helpers in the control groups unchanged.

Reproductive success, as measured by the number of fledglings, was significantly lower in the experimental group because they had fewer helpers.


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Using groups of gray-crowned bablers that range from an initial size of six to eight individuals. Brown and his colleagues removed all but one of the nonreproductive helpers from the experimental groups, while leaving the number of nonreproductive helpers I the control groups unchanged.Reproductive success, as measured by the number of fledglings, was significantly lower in the experimental groups because they had fewer helpers.


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Family dynamics The building blocks for family

dynamics 1. Inclusive fitness (kin selection

theory)2. Ecological constraints

theory3. Reproductive skew theory

Biological families (4/15 hypotheses)


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Biological families (4/15 prediction)1. Family dynamics will be unstable,

disintegrating ( 破碎 ) when acceptable reproductive opportunities materialize ( 突然出現 ) elsewhere.

2. Families that control high-quality resources will be more stable than those with lower-quality resources. Dynasties may form.

4. Cooperative breeding will be expressed to the greatest extent between those family members that are the closest genetic relatives.

9. Replacement mates (stepparents) will invest less in existing offspring than will biological parents.


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Family dynamics (prediction 1)1. Family dynamics will be unstable,

disintegrating( 破碎 ) when acceptable reproductive opportunities materialize( 突然出現 ) elsewhere.

This is the most basic prediction made by Emlen, as it focuses on fundamental costs and benefits associated with family life.

One technique for experimentally examining prediction 1 is to create new, unoccupied territories and examine whether mature offspring leave their natal area to live in such newly created areas. (Superb fairy wren) they did so, within 6 hours.


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In superb fairy wrens, young males often act as helpers-at-the –nest. When Pruett-Jones removed breeding males from their territories, almost all potential male helpers who could have dispersed to newly opened territories did so.


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In the superb fairy wren, male helpers often assist their parents. If a vacant territory opens up, however, male helpers are quick to leave the family unit and attempt to start their own family.


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Family dynamics (prediction 2)

2. Families that control high-quality resources will be more stable than those with lower-quality resources. Dynasties may form.

案例： acorn woodpeckers Territories varied from less than a 1,000 to

greater than 3,000 storage holes for acorns.Individuals on territories with lots of

storage holes produced a greater average number of offspring In the areas with more than 3,000

storage holes, 27%of the young remained on their natal territories and helped their relatives, while only 2% of the young on territories with fewer than 1,000 holes stayed.


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In cooperatively breeding acorn woodpeckers, the young not only survive better on territories with more storage holes, they are also more likely to remain on their natal territories throughout their life, creating a “family dynasty”. Such dynasties enable kin groups to compete for superior territories.


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Increasing territory size, and hence increasing number of storage holes, led to increase rate s of survival.


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Prediction 2 to human family dynamics

Well-to-do families being more stable than poorer families?If a stable family is defined in terms of

co-residence, then this prediction is not supported.

Wealthier individuals did keep in touch with relatives more often than did lower-income individuals High-income families are more likely to

maintain social ties at some level and to engage in exchange.


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Based on Emlen’s dynasty building hypothesis, Davis and Daly hypothesized that familial contact would be greater in wealthy human family units. The data from the 1991 Canadian General Social Survey support this general prediction.


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Family dynamics (prediction 4)

4. Cooperative breeding will be expressed to the greatest extent between those family members that are the closest genetic relatives.

案例： white-fronted bee-eater kinship and helping close relatives


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Inclusive fitness models of behavior have been tested extensively in white-fronted bee-eaters.


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In white-fronted bee-eaters, individuals are more likely to help those to whom they are more closely related .

For example, when interacting with genetic kin with r=0.5, birds dispensed aid 80 % of the time, but that percentage drops to less than 20% when r=0.125.


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Haplodiploid genetic systemHoneybee policing

Haploid males; Females, diploid(A) while the queen typically lays the eggs

in the honeybee colony, workers also attempt to lay unfertilized eggs.

(B) when an egg laid by a worker is detected by worker police, it is eaten or destroyed. Such “ policing” has inclusive fitness benefits associated with it.


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Honeybee policing(A) While the queen typically lays the eggs in the honeybee colony, workers also attempt to lay unfertilized eggs.(B) When an egg laid by a worker is detected by worker police, it is eaten or destroyed. Workers are much more likely to destroy eggs produced by other workers than eggs produced by the queen. Such “policing” has inclusive fitness benefits associated with it.


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In honeybees, where queens often mate with ten to twenty males, workers are more related to the male offspring of the queen (their brothers) than to offspring of other workers (their nephews). Workers police the hive and search out and eat the eggs of other workers.


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Wasp policing

(A)The wasp in the middle of the photo is a worker who has just laid an egg.

(B)here a worker is eating another worker’s egg. Policing is much more common in wasp colonies where the queen has mated with many males.


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The more effective policing was at removing worker eggs, the less often workers attempted to reproduce.


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Family dynamics (prediction 9)9. replacement mates (stepparents) will

invest less in existing offspring than will biological parents.

Child abuse and genetic relatedness in humans(A) two natural parents(B) one natural and one stepparent


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(A) The per capital rates of child abuse reported in 1980 by the American Humane Association in the United States. Rates of child abuse were significantly greater in households where one parent was not genetic kin.


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(B) The same relationship between child abuse and family type was also uncovered in Canada, as reported in 1983 by a provincial registry in Hamilton, Ontario.


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Conflict within familiesParent-offspring conflict

How much aid to give to any particular offspring? (parental investment)

案例：Parental investment and mating systems in

primatesIn-utero conflicts in humans

Sibling rivalry ( 對抗，競爭 )


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Parental investment and mating systems in primates

The hypothesis: offspring will attempt to extract more

resources from patents in polyandrous systems than in monogamous systems.

Fetuses grew faster in utero (taking more maternal resources) in polyandrous primate species

Because sperm competition is more intense in polyandrous species, males in such species tend to have larger testes.Testes size can often be used as a proxy for the

degree of polyandry.Fetal growth rate is positively corrected with the

testes size.


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Testes size tends to be larger in male from polyandrous vs. monogamous species. The relationship between testes size (a proxy measure of polyandry) and parent – offspring conflict (measured by fetal growth rate) was positive in analysis of primates.


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Mothers and babies.

While the patent-offspring relationship is usually cooperative (A), parent-offspring conflict can occur, even in utero as shown by an ultrasound (B)


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Sibling rivalrySib-sib conflict.

Kin selection theory predicts that individuals generally should not be very aggressive toward kin such as sibs.This is especially true when there are

abundant resources. But if there are limited resources,

conflict over the resources will increases.


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Sib-sib competition in egretsThey lay their eggs in sequence, rather

than all at one time. Thus, hatching order produces chicks that can differ in age by many days.

Such age differences play a critical role in determining who emerges as the victor in sib-sib interactions, since chicks that hatch first start to feed sooner and hence receive more food, which leads to a weight advantage over chicks that hatch laterLarge size means better fighting ability


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In nests of egrets, sib-sib competition can be intense and result in the death of smaller, less dominant chicks. Sibling rivalry can be seen in the fights between siblings in the nest, as shown, where one of the chicks is preparing to bite its sibling on the back of its head.


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Birth order and food intake(A) Normal broods of little blue herons include four to five chicks that are hatched asynchronously. The three eldest chicks (Chicks 1,2, and 3) are heavier than the youngest chicks (chicks 4 and 5). If younger chick is part of a brood in which one of its older sibs has died (lost sib), its average weight is less than that of its older sibs but more than it would be if it were in a brood in which no sibs had died (no loss).


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(B) In egret broods, the oldest, dominant chick (1) receives more food than the middle chick (2), who in turn gets more than the youngest chick (3). This holds for the early period after hatching (1-13days), the middle period (14-21 days), and the late period (21-30 days).


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Kin recognitionKin recognition in penguins Matching Model

Template matching in tadpolesMHC, kinship, and templates

Rule-of-thumb models of kin recognition


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Kin recognition in penguins.Kin recognition via vocal signatures has been examined in (A) the emperor penguin and (B) the king penguin. Both species of penguins live in large colonies, and parents returning from foraging with food for their chick use vocal cues to find their offspring in the midst of numerous other chicks.


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Matching models

Internal templateKin recognition matching models

Individual 1 determines if individual 2 is kin or nonkin, depending on how closely individual 2 matches the internal template of individual 1.

案例： Template matching in tadpolesKin recognition in spadefoot toads


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As in the spadefoot toad, two different tadpole morphs – a carnivorous cannibal and an herbivorous omnivore– exist in a number of amphibian species. Here a tiger salamander cannibal morph (right) is eating an omnivore morph (left).


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Spadefoot toad tadpoles come in two morphs: carnivorous and herbivorous. Individuals from each tadpole morph were placed between two groups of tadpoles,

Herbivorous morphs preferred kin sibs, while carnivorous morphs preferred nonkin.


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Kin recognition in spadefoot toads

Carnivores were not only more likely to eat unrelated individuals, but they were able to distinguish between relatives and nonrelatives by some sort of taste test.

That is, carnivores were equally likely to suck relatives and nonrelatives into their mouths, but they released their relatives much more frequently than unrelated individuals.

Cannibalistic toads were much less picky when they had been starved for 24 hours or more- that is, when they were very hungry, they would occasionally eat even genetic kin.


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The carnivorous morph of spadefoot toads prefers to eat nonkin over kin.When starved for 24 hours (A), only a little more than 10 percent of individuals eaten were kin. If starved for 48 hours, this figure rises. As a control, toads were again starved for 24 hours (C), and results were similar to the original 24-hour deprivation treatment (A). The solid horizontal line represents the value expected if cannibalism were random with respect to kinship.


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MHC, kinship, and templatesMHC (Major Histocompatibility Complex)

also plays a role in kin recognition.Which they identify by odor, to

determine which mate to choose.案例： House mice (Mus musculus domesticus).

When the female mice nest together, they all receive a benefit, which is protection from infanticidal males that sometimes attack and kill offspring that are not their own.

Ninety percent of the females chose to nest communally. (kin recognition, MHC)


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Rule-of-thumb models of kin recognition

if it lives in you nest/cave/territory, then treat it like kin.Such kin recognition rules are subject to

cheating例如， cowbirds and cuckoo birds (nest

parasites)Spatial cues and kin recognition rules can

often change through the lifetime of an individual. 例如： bank swallows,

幼鳥， in my burrow, it is likely kin學習飛行， using distinctive vocal cues


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Kin recognition breakdown.While adopting an “if it’s in your nest, it is your offspring” rule, the system can be sabotaged by “nest parasites”.Here a mother dunnock is feeding a baby cuckoo that has been dumped into her nest.A mother dunnock is feeding a baby cuckoo.


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Host species try to avoid being parasitized

Host species conceal and defend their nests Identify and remove the eggs (or young) of

parasitesBrood parasites try to deceive hosts

Cuckoos lay eggs in the late afternoon when hosts are less attentive

Parasitic eggs or young resemble those of the host species

Common cuckoo egg

Great reed warbler egg

Waxbills ( 織布鳥 )


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Whydah ( 寡婦鳥 )Parasitic

whydah( 寡婦鳥 )

Waxbill

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

問題與討論


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動物行為學 (通識 )

國立臺南大學通識課程 2011 年春

Documents

05 親緣關係 ( Kinship) 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

05 親緣關係 ( Kinship) 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