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Chap.02 The Evolution of
Behavior
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
The Evolution of Behavior
Artificial selection
Natural selection
Behavioral genetics
The modern theoretical framework
for animal behavior
 Sociobiology and selfish genes
 Antipredator behavior in guppies
Adaptation
Genetic techniques
phylogeny
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Both natural and artificial selection have produced many
morphological varieties of the pigeon.
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Pigeon breeders have selected for behavioral varieties of
pigeons, including (A) tumbler (輾轉的) pigeons, and (B)
homing pigeons.
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If hunting in larger groups (up to some maximum group size)
provides more food per dog than hunting in smaller groups
(or alone), natural selection can favor group hunting.
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When population size equals 100, the number of wild dogs
that hunt in groups will increase in frequency, and they will
eventually make up 100 percent of the population. No
mutation and no migration.
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Heritability (遺傳度)
 Selection differential, S
 Generation 1 天擇下，可繁殖後代的平均值(X1) 扣
除 目前世代的平均值 (X0)。
 譬如， X0 =60秒 X1=90秒 S=90-60=30
 Response, R
 Generation 2的平均值 (X2) 扣除 Generation 1的平
均值 (X0)。
 譬如，X2=70秒 R=70-60=10
 Heritability, h2
 h2 = R/S = 10/30 = 0.33
 形態和行為
 h2 = Low 0.0-0.1， moderate 0.1-0.4
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Behavioral genetics
1. Using Mendel’s laws of genetics to
predict the distribution of behavioral
phenotypes
2. Mapping genes for behavioral traits
3. Using other measures of heritability
to determine what percentage of the
variation in a behavioral trait is
genetic and what percentage is
environmental.
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Some of differences in the mating behavior of (A) satellite
males and (B) independent males are controlled by a
single gene with two alleles labeled S and s. The S allele
is dominant and codes for satellite male behavior, while
the s allele is recessive. The ss is for independent males.
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Polygenic traits
Quantitative trait loci (QTLs)
Fear/fearlessness in mice (Flint, et al.,
1995)
測試 mice 於 open-field behavior (fear)
選擇the more fearfull mice, 分析其DNA
相關fear的基因存在於，six different
chromosomes (1,4,12,15,17和18)。
倘若是走迷宮的fear，則存在於
chromosomes (1,12,和15)。
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Dissecting behavioral variation
• Parent-offspring regression
• Breeding colony size in
parents and offspring (Fig.2.11)
• Cross-fostering experiment
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The modern theoretical
framework for animal
behavior
Antipredator behavior
in guppies
 (A) an upstream,
low-predation
stream, and
 (B) a downstream,
high-predation
stream.
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Male
Female
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(A)A pike cichlid, Crenicichia alta. These predators are
common in downstream sites native to guppies.
(B) A killifish, Rivulus hartii. These small, fairly innocuous
predators can eat only tiny guppies and are found in
upstream sites.
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(A)Group size where there is low-predation pressure leads to a
preference for small groups.
(B)Group size where there is medium to high predation pressure.
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(C) Groups size where there is very-high predation pressure
leads to a preference for larger group sizes.
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Here, some guppies from high-predation sites are
transplanted to low-predation sites, and vice versa.
Over the courses of several years, transplanted populations
converge on the characteristics of the fish in the populations into
which they were transplanted.
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Adaptation
 In more than 100 different species of birds,
females engage in brood parasitism.
 While waterfowl make up only about 2 percent
of bird species, they account for more than 25
percent of the cases of parasitic egg dumping.
 Semel and Sherman found that a remarkable
95% of active nests were parasitized, despite
many empty nest boxes that could be used to
raise young.
 Wood ducks that nest in man-made boxes in
Missouri
 Many heavily parasitized nests were simply
abandoned by the wood ducks, and no eggs in
such nests hatched.
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(A)A male and female
wood duck at a manmade nesting box.
(B) many different wood
ducks lay their eggs in
the same nest.
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Five hypotheses
1. Dump eggs to reduce the risk of predation on
all their eggs at once, thereby engaging in
what is called “bet hedging”.
2. Be forced to parasitize the nests of others for
lack of suitable, hidden nests.
3. Parasitze when their own nest is destroyed
4. Gain some benefit by placing eggs in the nests
of genetic relatives.
5. Enhance their reproductive success in general
by simply laying eggs in any available nest
they come across.
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Maladaptations
When nest boxes were not present and
good territories were dispersed
throughout the environment, there was
likely a very high premium placed on
finding good cavities in which to nest.
Thus, females may have egg dumped in
such cavities, and they may have
benefited from such parasitism.
But when nest boxes were present and
clumped, such egg dumping was no
longer adaptive. (Fig. 2.21)
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Kinship and naked mole rat behavior
Genetic techniques to test hypotheses in animal behavior
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(結盟)
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Phylogeny and the study of
animal behavior
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Phylogenetic trees
Phylogenetic trees
 Homology(同源) vs. homoplasy (同功)
 Convergent evolution（趨同演化）
 Polarity （極向）
Parsimony analysis（吝嗇分析）
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Phylogeny and parental care
Ray-finned fish (硬骨魚類)
 There are of families, mad up of over
20,000 species.
 High variety of parental care
To build a phylogenetic tree of 224
families of ray-finned fish and examined
the evidence for parental care. (Mank et
al, 2005)
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Phylogeny and parental care
1. Fish paternal care evolved on 21 independent
occasions.
2. Maternal care and biparental care also
evolved independently numerous times.
3. Maternal care tended to evolve after species
had moved from external to internal
fertilization.
4. Paternal care was often found alongside
intense male coloration and nest construction
(external fertilization)
5. Male coloration was also associated with
systems in which females fertilized eggs
internally.
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Phylogeny, mating systems, and
male aggression
Male fighting one another for access to
females, since the payoff for such
aggression.
If sexually receptive females are not
present, the costs of males fighting one
another may outweigh the benefits.
Wasps of the genus Nosonia lay their
eggs inside a host species, and their
larvae feed on the host as they develop.
Three species of Nasonia, N. vitripennis.,
N. giraulti and N. libgucirnus.
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問題與討論
Ayo NUTN website:
http://myweb.nutn.edu.tw/~hycheng/