Selling an Idea or a Product

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Mating Behavior I. Sexual reproduction A.
Why do it? 1. Costs -- pass on only
50 of genome/offspring -- energetically
expensive -- risk of predation --
risk of disease
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Mating Behavior I. Sexual reproduction A.
Why do it? 2. Benefits -- increased
genetic variability in offspring -- better
foragers, etc. -- increased resistance to
disease
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Mating Behavior I. Sexual reproduction B.
Why have different sexes?
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Mating Behavior I. Sexual reproduction B.
Why have different sexes? sexual
reproduction fertilization development gend
er specialization on one component of
reproduction Evolutionarily Stable
Strategy (ESS) cannot be invaded or replaced by
an alternate strategy
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Gamete size in ancestral population
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Tiny gamete specialized for fertilization male
Huge gamete specialized for development
female
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Mating Behavior I. Sexual reproduction C.
Consequences of separate sexes 1.
differences in parental investment (PI)
-- any investment in a current offspring that
reduces ability to invest in future
offspring -- general rule female PI gt
male PI paternity assurance
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Mating Behavior I. Sexual reproduction C.
Consequences of separate sexes 2. different
reproductive strategies female strategy --
success depends on development of limited number
of expensive gametes. -- reproductive success
usually is NOT increased by mating with multiple
males for a given breeding attempt one
male fertilizes all available eggs. -- mistakes
in mate selection are costly. -- female is
selected to be choosey and resist males attempts
to mate
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Mating Behavior I. Sexual reproduction C.
Consequences of separate sexes 2. different
reproductive strategies male strategy --
success depends on fertilization. --
reproductive success usually is directly
proportional to number of sexual
partners -- mistakes are less costly --
male is selected to be promiscuous and less
choosey
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Mating Behavior I. Sexual reproduction C.
Consequences of separate sexes 3. Sexual
Selection the selective pressures that
conspecifics place on one another as they compete
for mates and choose sexual partners
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Mating Behavior II. Sexual Selection A.
Intrasexual competition (usually male-male
competition) 1. factors influencing degree of
competition a. Inequality of PI less
male PI, more male-male competition
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• Mating Behavior
• II. Sexual Selection
• A. Intrasexual competition (usually
  male-male competition)
• 1. factors influencing degree of competition
• b. operational sex ratio
• sexually receptive males/sexually
  receptive females
• If high (many males/female) male biased
  operational sex ratio
• increased male competition
• If low (few males/female) female biased
  operational sex ratio
• can get competition among females
• for males

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Mating Behavior II. Sexual Selection A.
Intrasexual competition (usually male-male
competition) 1. factors influencing degree of
competition c. Distribution of
females -- if clumped and defendable
increased male competition harems -- if
widespread and undefendable decreased
competition monogamy lekking
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Mating Behavior II. Sexual Selection A.
Intrasexual competition (usually male-male
competition) 1. factors influencing degree of
competition d. Sperm competition when
female mates with more than one male for a
given batch of eggs, and one males sperm has
an advantage -- last male sperm
precedence -- selects for male strategies to be
the last or only male to mate
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Mating Behavior II. Sexual Selection A.
Intrasexual competition (usually male-male
competition) 2. mechanisms of competition
a. reduced threshold for arousal use of
sign stimuli
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Mating Behavior II. Sexual Selection A.
Intrasexual competition (usually male-male
competition) 2. mechanisms of competition
a. reduced threshold for arousal use of
sign stimuli
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Mating Behavior II. Sexual Selection A.
Intrasexual competition (usually male-male
competition) 2. mechanisms of competition
a. reduced threshold for arousal use of
sign stimuli
amplexus
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Mating Behavior II. Sexual Selection A.
Intrasexual competition (usually male-male
competition) 2. mechanisms of competition
b. male aggression
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Mating Behavior II. Sexual Selection A.
Intrasexual competition (usually male-male
competition) 2. mechanisms of competition
b. male aggression contested
resources a) dominance
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Mating Behavior II. Sexual Selection A.
Intrasexual competition (usually male-male
competition) 2. mechanisms of competition
b. male aggression contested
resources b) clumped females harems
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Mating Behavior II. Sexual Selection A.
Intrasexual competition (usually male-male
competition) 2. mechanisms of competition
b. male aggression contested
resources c) territory foraging site
oviposition site
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Mating Behavior II. Sexual Selection A.
Intrasexual competition (usually male-male
competition) 2. mechanisms of competition
b. male aggression contested
resources c) territory lek
sage grouse courtship video
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Mating Behavior II. Sexual Selection A.
Intrasexual competition (usually male-male
competition) 2. mechanisms of competition
b. male aggression contested
resources c) territory lek
prairie chicken courtship video
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Mating Behavior II. Sexual Selection A.
Intrasexual competition (usually male-male
competition) 2. mechanisms of competition
c. Sperm competition 1) modified penis
Female insect has spermatheca
damselfly courtship video
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Mating Behavior II. Sexual Selection A.
Intrasexual competition (usually male-male
competition) 2. mechanisms of competition
c. Sperm competition 1) modified penis
Female insect has spermatheca
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Mating Behavior II. Sexual Selection A.
Intrasexual competition (usually male-male
competition) 2. mechanisms of competition
c. Sperm competition 1) modified penis
Female insect has spermatheca
damselfly courtship video
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Mating Behavior II. Sexual Selection A.
Intrasexual competition (usually male-male
competition) 2. mechanisms of competition
c. Sperm competition 1) modified penis
traumatic insemination of bedbug
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bedbug mating video
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Mating Behavior II. Sexual Selection A.
Intrasexual competition (usually male-male
competition) 2. mechanisms of competition
c. Sperm competition 2) mate guarding
-- cost lost opportunities to mate
with additional females -- benefits
increase with probability that unguarded
female will mate again and use sperm of 2nd
male
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Mating Behavior II. Sexual Selection A.
Intrasexual competition (usually male-male
competition) 2. mechanisms of competition
c. Sperm competition 2) mate
guarding ex Seychelles warbler
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-- Females lay only a single egg -- Males guard
females during fertile period (4 days before
laying egg) after egg is laid, male guarding
stops -- females will engage in extra-pair
copulations (EPC) -- amount of guarding increases
with number of neighboring males
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-- Placed false egg in nest 4 days before female
was to lay -- Tricked male into ending guarding
prematurely -- EPC extra-pair copulation
Unmanipulated
Manipulated
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Mating Behavior II. Sexual Selection A.
Intrasexual competition (usually male-male
competition) 2. mechanisms of competition
c. Sperm competition 3) prolonged or
repeated copulation
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Mating Behavior II. Sexual Selection A.
Intrasexual competition (usually male-male
competition) 2. mechanisms of competition
c. Sperm competition 3) prolonged or
repeated copulation ex forced copulation
in mallard ducks
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Mating Behavior II. Sexual Selection A.
Intrasexual competition (usually male-male
competition) 2. mechanisms of competition
c. Sperm competition 4) mating plugs
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Mating Behavior II. Sexual Selection A.
Intrasexual competition (usually male-male
competition) 2. mechanisms of competition
c. Sperm competition 5) toxic chemical
fruitflies

• seminal fluid of males contains protein (ACp62F)
• -- increases male fertilization success by
  damaging rival sperm
• -- shortens females life lowers female
  fecundity
• Males mate with multiple females, so total
  reproductive success is increased

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Mating Behavior II. Sexual Selection A.
Intrasexual competition (usually male-male
competition) 3. evolutionary consequences of
male-male competition a. sexual
dimorphism weaponry
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Mating Behavior II. Sexual Selection A.
Intrasexual competition (usually male-male
competition) 3. evolutionary consequences of
male aggression a. sexual dimorphism
weaponry
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Mating Behavior II. Sexual Selection A.
Intrasexual competition (usually male-male
competition) 3. evolutionary consequences of
male aggression b. honest signals
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Song repertoires Repertoire size honest
indicator of male fighting ability and quality.
Size varies with -- age -- health
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Mating Behavior II. Sexual Selection A.
Intrasexual competition (usually male-male
competition) 3. evolutionary consequences of
male aggression c. alternate male
mating strategies 1) strategies that convey
unequal benefits -- are conditional
male strategy varies with his size, health,
dominance status, behavior of other males,
etc. -- allow subordinate or smaller
males to make the best of a bad situation

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• Mating Behavior
• II. Sexual Selection
• A. Intrasexual competition (usually
  male-male competition)
• 3. evolutionary consequences of male
  aggression
• c. alternate male mating strategies
• 1) strategies that convey unequal benefits
• a) scorpionfly, Panorpa
• 3 male strategies
• Guard dead insect
• Salivary secretion
• Force copulation

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scorpionfly Panorpa experimental set up 10
males 10 females in cage with dead
crickets
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scorpionfly Panorpa experimental set up next,
removed the large males defending dead
crickets

• some males abandoned salivary secretions and
  guarded crickets
• some of the small males claimed the salivary
  secretions abandoned
• by the males to defend crickets
• ? males adopt the strategy that will maximize
• their mating chances, given current competitive
  status

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Mating Behavior II. Sexual Selection A.
Intrasexual competition (usually male-male
competition) 3. evolutionary consequences of
male aggression c. alternate male
mating strategies 1) strategies that convey
unequal benefits b) satellite
males -- subordinate males position themselves
around dominant male and try to intercept
females and sneak copulations -- have lower
reproductive success than dominant male

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Mating Behavior II. Sexual Selection A.
Intrasexual competition (usually male-male
competition) 3. evolutionary consequences of
male aggression c. alternate male
mating strategies 1) strategies that convey
unequal benefits c) female
mimicry -- subordinate males mimic female
behavior -- dominant individual allows them to
stay nearby can then attempt to sneak
copulations -- have lower reproductive success
than dominant male
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female mimicry ex hanging flies -- males
give female nuptial gift catches insect, then
hangs from vegetation and emits pheromone to
call female -- food gift difficult to
obtain many males caught by predators when
searching for food gift -- some males will
approach a calling male with a gift and act
like a female -- steal nuptial gift and use it
to attract females themselves
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• female mimicry
• ex bluegill sunfish 3 male strategies
• A. Large, dominant males guard territory to
• attract female females prefer these males
• B. Small, sneaker satellite males attempt to
  dash
• between spawning pair and release milt when
• territorial male does
• C. Mid-sized satellite males have coloration
• pattern of female hovers above nest and
• slips between territorial male and female
• when she spawns

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Mating Behavior II. Sexual Selection A.
Intrasexual competition (usually male-male
competition) 3. evolutionary consequences of
male aggression c. alternate male
mating strategies 1) strategies that convey
unequal benefits d) male
coalitions
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Mating Behavior II. Sexual Selection A.
Intrasexual competition (usually male-male
competition) 3. evolutionary consequences of
male aggression c. alternate male
mating strategies 2) strategies that convey
equal benefits a) gray seals

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• ex. Gray seals
• Combatant males fight on the beach
• to monopolize harems of females
• Noncombatant males remain
• offshore and mate with females
• swimming to colony
• DNA fingerprinting reveals that
• combatant and noncombatant males
• father similar number of young

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Mating Behavior II. Sexual Selection A.
Intrasexual competition (usually male-male
competition) 3. evolutionary consequences of
male aggression c. alternate male
mating strategies 2) strategies that convey
equal benefits b) sponge
isopods
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sponge isopod, Paracerceis sculpta males occur
in three, genetically determined sizes
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• sponge isopod
• Alpha males dominant battle to exclude other
  males
• from sponge will physically evict
• gamma males
• Beta males female mimics will be courted by
  Alpha
• male and allowed to remain in sponge
• gain access to females
• Gamma males avoid Alpha males hide in sponge
  and
• attempt to sneak copulations

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• sponge isopod
• -- size differences in males result from a single
  gene
• with 3 alleles
• -- created various combinations of males and
  females in
• artificial sponges used genetic markers to
  determine paternity
• of resulting offspring
• -- reproductive success of each type depended on
  number of
• other males and females in sponge
• 1 alpha 1 beta 1 female alpha fathered 100
• 1 alpha 1 beta 2 females beta fathered 60
• In other combinations, gamma fathered most
• offspring
• Average no. of mates
• -- alpha 1.51
• -- beta 1.35
• -- gamma 1.37
• (P gt 0.05)