III. Sex and SelectionA.Costs and Benefits (notes)

III. Sex and SelectionA.Costs and Benefits (notes)B.Sexual Selection - selective pressures may differ between the sexes, resulting in selection for different physiologies, morphologies, and behaviors.1.Mating Systems: - should you have many mates or one mate?

# mates

# of

fspr

ing

male

female

NEWTS

Jones (2002)

III. Sex and SelectionA.Costs and Benefits (notes)B.Sexual Selection - selective pressures may differ between the sexes, resulting in selection for different physiologies, morphologies, and behaviors.1.Mating Systems: - should you have many mates or one mate?

# mates

# of

fspr

ing

male

female

PIPEFISH

Jones (2002)

III. Sex and SelectionA.Costs and Benefits (notes)B.Sexual Selection - selective pressures may differ between the sexes, resulting in selection for different physiologies, morphologies, and behaviors.1.Mating Systems:2. Intrasexual Selection – where competition within a sex occurs

Sexual Selection

2. INTRAsexual Competition - competition for harems, territories

Sexual Selection

2. INTRAsexual Competition - competition for harems, territories - sperm competition

Sexual Selection

2. INTRAsexual Competition - competition for harems, territories - sperm competition - infanticide

Sexual Selection

2. INTRAsexual Competition - competition for harems, territories - sperm competition - infanticide - female mimicry in male subadults and "stealth matings"

"sneaker males"

FEMALE

"Sneaker" male

Sexual Selection

3. INTERsexual Selection (Mate Preference) - A behavior or morphology that is only performed during the

reproductive season, which increases risk and must then be offset by mating

Sexual Selection

3. INTERsexual Selection (Mate Preference) - A behavior or morphology that is only performed during the

reproductive season, which increases risk and must then be offset by mating

showy breeding plumagecalling displays

3. INTERsexual Selection (Mate Preference)- WHY is it ADAPTIVE for the FEMALE to choose a given male??

1. Direct Benefit - parental care

3. INTERsexual Selection (Mate Preference)- WHY is it ADAPTIVE for the FEMALE to choose a given male??

1. Direct Benefit - nuptual gifts (energy for egg making)

3. INTERsexual Selection (Mate Preference)- WHY is it ADAPTIVE for the FEMALE to choose a given male??

1. Direct Benefit2. Indirect Benefit: Good Genes - ‘Handicap Theory’

3. INTERsexual Selection (Mate Preference)- WHY is it ADAPTIVE for the FEMALE to choose a given male??

1. Direct Benefit2. Indirect Benefit: Good Genes - ‘Parasite Load Theory’

Hmmm....

3. INTERsexual Selection (Mate Preference)- WHY is it ADAPTIVE for the FEMALE to choose a given male??

1. Direct Benefit2. Indirect Benefit: Good Genes - ‘Symmetry Theory’

Hmmm....

3. INTERsexual Selection (Mate Preference)- WHY is it ADAPTIVE for the FEMALE to choose a given male??

1. Direct Benefit2. Indirect Benefit: Good Genes - ‘Symmetry theory’

Hmmm....

Hey, It Works!!

3. INTERsexual Selection (Mate Preference)- WHY is it ADAPTIVE for the FEMALE to choose a given male??

1. Direct Benefit2. Indirect Benefit: Good Genes - ‘Symmetry Theory’

3. INTERsexual Selection (Mate Preference)- WHY is it ADAPTIVE for the FEMALE to choose a given male??

1. Direct Benefit2. Indirect Benefit: Good Genes3. Runaway Selection