100, Psych Prof. Mark Hauber
How to write a successful synopsis?
Read the Abstract, then read the paper carefully of the CUCKOO PDF article (posted
on Blackboard).
Look through the Figures and read the Figure Legends.
Read the Title and Abstract again to see if the paper delivers its promise.
To write the synopsis: 1 page printed max, single or double spaced, 12 font.
Please put your full name, course number, and your iClicker ID # on the top of the
page.
Bring the synopsis to class on Monday Sept 19 NO LATE ASSIGNMENTS OR
Bring the synopsis to class on Monday, Sept. 19. NO LATE ASSIGNMENTS OR
EMAILED ASSIGNMENTS WILL BE ACCEPTEDyou CAN bring the synopsis to
class BEFORE the deadline.
http://www.youtube.com/watch?v=dAU5MTXmAPY
Host-parasite co-evolutionary interactions:
forces of natural selection
Fitness value: 0!?
Selection on parasite to fit in:
mimicry of eggs
In Cuculus cuckoos but not in Molothrus cowbirds
Great reed warblers and common cuckoos:
near perfect mimicry
near perfect mimicry
Great reed warbler
Great reed warbler-cuckoos lay highly
lay highly
mimetic eggs, with intermediate
rejection rates of natural parasitism by
hosts (34%).
(34
Full-spectrum reflectance of eggshells
What explains diversity of host
responses
responses
at the cognitive level?
Optimal conspecific acceptance threshold theory
conspecific
threshold theory
(Reeve 1989):
provides a fitness-based integrative explanation for variability of discrimination
decisions by proposing that cognitive mechanisms evaluate host-parasite trait
dissimilarity within a selection-sensitive framework.
Experimental tests of optimal threshold theory:
increased risk of parasitism vs. rejection decisions
risk of parasitism vs. rejection decisions
Prediction:
Experience with experimental parasitism shifts
the acceptance thresholds to more restrictive limits
Manipulating host egg traits:
1
Control
Speckled
All brown
Experimental test of optimal threshold theory:
increased risk of parasitism vs. rejection decisions
risk of parasitism vs. rejection decisions
1.0
Rejection Rate
0.8
0.6
0.4
0.2
0.0
13
0Control
17
1
14
2
sample sizes (nests)
3
Experimental test of optimal threshold theory:
increased risk of parasitism vs. rejection decisions
risk of parasitism vs. rejection decisions
1.0
Rejection Rate
0.8
0.6
0.4
0.2
0.0
13
0Control
17
1
14
2
3
12
Experimental test of optimal threshold theory:
increased risk of parasitism vs. rejection decisions
risk of parasitism vs. rejection decisions
1.0
Rejection Rate
0.8
0.6
0.4
0.2
0.0
13
0Control
17
1
14
2
12
3
Hauber et al. 2006
Psych 100, Prof. Mark Hauber
How to write a successful synopsis?
Read the Abstract, then read the paper carefully of the CUCKOO PDF article (posted
on Blackboard).
Look through the Figures and read the Figure Legends.
Read the Title and Abstract again to see if the paper delivers its promise.
To write the synopsis: 1 page printed max, single or double spaced, 12 font.
Please put your full name, course number, and your iClicker ID # on the top of the
page.
Bring the synopsis to class on Monday Sept 19 NO LATE ASSIGNMENTS OR
Bring the synopsis to class on Monday, Sept. 19. NO LATE ASSIGNMENTS OR
EMAILED ASSIGNMENTS WILL BE ACCEPTEDyou CAN bring the synopsis to
class BEFORE the deadline.
To compose the synopsis:
1. Start with the summary of the broad topicwhat is the general topic,
theoretical
relevance of the paper.
2. State the specific topic that the paper considers.
3. Are there any/what are the hypotheses tested?
4. What are the methods briefly: observations, experimental, modeling,
etc.
5. Key result(s)/pattern of data/directional effects of manipulations.
6. Discussiondoes it address the data/does it follow from the
results/does it fit within the general framework/topic of the paper.
7. Your own critique/opinion of the work; a sentence about what can be
done next?
Grading criteria for Synopsis assignment:
10 pts max.
T: Theoretical background: why is egg recognition important:1 pts.
D: Definitions of the concepts in the article (i.e. brood parasitism and egg rejection):
1 pt.
pt
H: Hypothesis (was the hypothesis/prediction of the study clearly stated)? 1 pt.
M: Methods of the study described (observational component, experimental
component): 2 pts.
R: Results of the study described (quantitative/numerical outcomes, patterns,
Results of the study described (quantitative/numerical outcomes patterns
significance): 2 pts.
C: Conclusions of the study stated clearly: 1 pt.
P: Personal insight, your own opinion of the study: 1 pt.
F: Future work, extension, additional study and direction suggested by you: 1 pt.
Future work, extension, additional study and direction suggested by you: pt.
On Blackboard, under the PDF document SUCCESSFUL SAMPLE SYNOPSIS, based on a
different article (also provided) than the article assigned to you in this course.
competition
for mates
mate choice
mate choice
Two Components of
Components of
Cues for Decisions:
Intersexual
selection
Intrasexual
selection
mate choice
choice
Typical sex roles
Typical sex roles
competition
for mates
Two components of
components of
sexual selection:
Intersexual
selection
Intrasexual
selection
Mechanisms of inter-sexual selection
Mate choice (Pre-copulatory):
selection of copulatory partner
(discrimination among suitors)
Favours
particular male
phenotypes
Cryptic choice (Post-copulatory):
Paternity-biasing mechanisms
mechanisms
differential sperm use
remating or extra-pair mating
or extra
mating
variation in timing of egg laying
Differential allocation
variation in egg / offspring investment
What are females choosing?
1. Direct Benefits: females choose males that
directly increase female reproductive success
nutrients (nuptial gifts)
territories
low risk of parasite transmission
parental care
females assess resource directly
di
OR
females choose males with traits that are
choose males with traits that are
honest indicators of parental skill
What are females choosing?
2. Indirect Benefits: females choose males that
provide genes that increase the success of their
offspring
a) Fisherian (runaway) selection
Fisherian (runaway) selection
sexy sons hypothesis
females choose males that are attractive
choose males that are attractive
to many females, their will sons also be attractive
before selection
runaway process
elaboration of trait
correlated evolution of
evolution of
preference
male trait size, z
trait size
female preference, y
preference
after selection
male trait size after selection
trait size after selection
Genetic correlation between trait & preference due to assortative mating
equilibrium:
further elaboration of
trait halted by survival
halted by survival
selection (acting in
opposition to sexual
selection)
before selection
male trait size, z
after survival
selection
z
after survival
& sexual
selection
female preference, y
z
What are females choosing?
a) Fisherian (runaway) selection
sexy sons hypothesis
females choose males that are attractive
to many females, their sons will also be attractive
e.g., Stalk-eyed flies
Stalk
flies
What are females choosing?
a) Fisherian (runaway) selection
Prediction: a genetic correlation between trait & preference
Field-collected flies
Natural mating
Largest males
mate
Smallest males
mate
13 generations of artificial selection
Long eyestalks
Long eyestalks
Short eyestalks
Selection on stalks leads to selection on preference
a) Fisherian (runaway) selection
Prediction: a genetic correlation between trait & preference
Female choice
choice
Control:
Large males
Large males
-1.5
Difference in
# females
preferring L
versus S
males
0
-1.5
Wilkinson & Reillo 1994.
Large males
Small males
What are females choosing?
a) Fisherian (runaway) selection
Prediction: a genetic correlation between trait & preference
Females should carry genes for male traits as well as
should carry genes for male traits as well as
preferences.
e.g., alternative male sexual
alternative male sexual
morphs in ruffs
Independent males:
Establish display territories, high
rate of display
rate of display
Satellite males: associate
with Independent males, much
lower display rate
Fisherian (runaway) selection
Female ruffs: dull plumage
approach male displays but
do not display themselves.
Experiment: Induce expression of male traits
Experiment: Induce expression of male traits
Implant female ruffs with testosterone
Do females display courtship
females display courtship
behaviour typical of their fathers morph?
Lank et al. Proc. R Soc. 1999
Females carry traits preferred by their mothers
Independent father
%
females
Satellite father
More Satellite
behaviours
P < 0.001
More
Independent
behaviours
What are females choosing?
2. Indirect Benefits: females choose males that
provide genes that increase the fitness of their
offspring
a) Fisherian (runaway) selection
Fisherian (runaway) selection
b) Good genes selection
females choose traits that indicate high
heritable viability overall
or best compatibility with her own genes/genome.
Good genes
(i) traits indicate high heritable viability
developmental stability
fluctuating asymmetry
Good genes
Fluctuating Asymmetry (FA)
small, random deviations from perfect
random deviations from perfect
bilateral symmetry
deviations introduced during development
due to failures in homeostatic mechanisms
often results from exposure to harmful chemicals
or pathogens or parasites during development
pathogens or parasites during development
low degrees of FA = heritable, high developmental
degrees of FA heritable high developmental
stability
Good genes
Fluctuating Asymmetry (FA)
0
0
|Right Left|
toe length
Right Left
toe length
length
Prediction: increased parasite
stress during development
should increase FA
Fluctuating asymmetry
e.g., Drosophila nigrospiracula
natural parasites:
nematode (attacks during larval stage,
found in adults)
mite (only attacks adults)
compare FA in parasitized (nematodes or mites)
& unparasitized (control) flies
Polak. 1993. Genetica. 89:255-265
Fluctuating asymmetry
Nematodes: effects during development
Mites: no effects during development
2.7
2.4
mean bristle
mean bristle
FA
2.1
1.8
1.5
1.2
control
Polak. 1993. Genetica. 89:255-265
mites
nematodes
P = 0.0013
Fluctuating asymmetry
e.g., Homo sapiens
Does FA predict fitness?
FA predict fitness?
rural Belize, birth control uncommon
FA measured: wrist breadth, elbow breadth,
ear breadth, ear length, finger length (4)
breadth ear length finger length (4)
n = 56 men
Waynforth. 1998. Proc Royal Soc. 265:1497-1501
Fluctuating asymmetry
Does FA predict fitness?
FA predict fitness?
e.g., Homo sapiens
Variable
p<
# offspring
0.01
-
56
infant mortality
0.46
+
37
# major illnesses
major illnesses
0.02
+
56
# sex partners
0.10
-
33
Waynforth. 1998. Proc Royal Soc. 265:1497-1501
n
Good genes
(i) traits indicate high heritable viability
developmental stability
fluctuating asymmetry
resistance to parasites (Hamilton & Zuk)
to parasites (Hamilton Zuk)
Good genes
(ii) traits indicate genetic compatibility
e.g., MHC alleles
= major histocompatibility complex
major histocompatibility complex
highly polymorphic genes
control immunological self/non-self recognition
more variability = enhanced immune system
Prediction: females should prefer to mate with
males with dissimilar MHC haplotypes
with dissimilar
haplotypes
Smelly t-shirt studies
Female mice preferentially
mice preferentially
associate with soiled
bedding from MHC
dissimilar males:
Female Savannah
Sparrows preferentially
cuckold males with
similar MHC haplotypes
Disassortive mating with
respect to HLA (Human
Leukocyte Antigen ),
women discriminate
between similar and
dissimilar mens t-shirts
irrespective of familiarity
Nice smile but does
Nice smile but does
he smell like dad?
http://www.youtube.com/watch?
v=pEmX8Rim-hs
Serial monogamy in humans:
40
Age Differ ence from Spouse
30
30
20
10
Women
0
Men
-10
-20
-30
-40
20
30
40
50
Age (years)
60
70
80
Or Polygynandry?
Polygynandry
Does it imply a lack of mate choice?
Human mate choice is not random (p < 0.0016)
41
Increasing city size
McGraw KJ 2002 (Ethology). Human mate choice patterns from
lonely heard ads
42
Polygynandry in humans:
ygy
does it imply a lack of mate choice?
Fitness benefits of mate choice:
14
Number of Children
12
Actors:
10
8
Women
6
Men
4
2
Cumulative
Spouse Number
0
0
1
2
3+
Cummulative
Spouse Number
Hauber (2007) : http://news.sciencemag.org/sciencenow/2007/05/04-03.html