Natural
Selection
www.ldjackson.net
www.galenfrysinger.com
Natural
Selection
www.ldjackson.net
www.galenfrysinger.com
?
Selection
www.realbollywood.com
www.valentine.gr
Natural
Selection
www.ldjackson.net
www.galenfrysinger.com
Sexual
Selection
www.realbollywood.com
www.valentine.gr
Natural
Selection
•
Differential
fitness
due
to
variation
in
traits
Natural
Selection
•
Differential
fitness
due
to
variation
in
traits
Sexual
Selection
•
Differential
mating
or
fertilization
success
due
to
variation
in
traits
Sexual
Selection
•
Competition
for
mating/fertilization
opportunities
www.photogalaxy.com
www.photogalaxy.com
Sexual
Selection
•
Competition
for
mating/fertilization
opportunities
www.photogalaxy.com
www.realbollywood.com
www.photogalaxy.com
www.valentine.gr
Why
Are
There
Males
and
Females?
What
Are
Males
and
Females?
♀
=
few
large
gametes
♂
=
many
small
gametes
www.art.com
What
Are
Males
and
Females?
♀
=
few
large
gametes
♂
=
many
small
gametes
Bjork
&
Pitnick
(2006)
www.art.com
malct32.blogspot.ca
Why
Are
There
Different
Sexes?
‐
‐
+
+
‐
+
Why
Are
There
Different
Sexes?
‐
‐
+
+
‐
+
Why
Are
There
Different
Sexes?
+
+
+
+
+
‐
+
‐
‐
Why
Are
There
Different
Sexes?
+
+
‐
+
‐
‐
Why
Are
There
Different
Sexes?
+
+
‐
+
‐
‐
‐
‐ ‐
‐
‐
‐
Why
Are
There
Different
Sexes?
♀
♂
Why
Are
There
Different
Sexes?
♀
♂
Differences
Between
the
Sexes
♀
•
fitness
limited
by
resources
♂
•
fitness
limited
by
mates
Mosquitofish
Clutch
Size
♀
♂
♀
Standard
Length
(mm)
Meffe
&
Snelson
(1993)
gonopodium
Gambusia
holbrooki
Phalaropes
♀
♂
www.birdfellow.com
Differences
Between
the
Sexes
Choosy
Sex
Competitive
Sex
Sexual
Selection
…at
the
gametic
level
Bjork
&
Pitnick
(2006)
malct32.blogspot.ca
Sexual
Conflict
•
Traits
that
help
males
can
hurt
females
insects.eugenes.org
Drosophila
melanogaster
Seminal
fluid
proteins:
•
Reduce
♀
remating
rate
•
Reduce
♀
lifespan
Sexual
Conflict
•
Monogamy
reduces
competition
over
fertilization
♀
♂
Cooperation
♀
♂
♂
Conflict
Mating
System
&
Male
Competition
Pitnick
&
Hosken
(2011)
Mating
System
&
Male
Competition
wikipedia.org
www.faceoftomorrow
flicker.com
www.monkey‐pictures.net
Pitnick
&
Hosken
(2011)
Alternative
Male
Mating
Behaviours
Low
Competition
♀
High
Competition
♂
♀
♂
♂
Alternative
Male
Mating
Behaviours
♂‐♂
Interactions
%
Mating
Attempts
%
Mating
Success
♂‐♀
Interactions
α
100
80
60
40
β
20
γ
δ
0
Male
length
(relative
to
female)
1
2
3
#
Males
4
Bisazza
&
Marin
(1995)
Why
Do
Females
Have
“Preferences”?
•
Males
differ
in:
•
Resource
quality
Why
Do
Females
Have
“Preferences”?
•
Males
differ
in:
•
Resource
quality
•
Genetic
quality
Why
Do
Females
Have
“Preferences”?
•
Males
differ
in:
•
Resource
quality
•
Genetic
quality
•
Ability
to
seduce/manipulate
females
xworld.250free.com
Nuptial
Gifts
in
Dance
Flies
•
Nutritious
prey
items
•
Dried
insect
fragments
•
Inedible
tokens
LeBas
and
Hockham
2005