animal comm exam 2 mates

anisogamy

differences in size and motility of gametes

Operational sex ratio

differences in ratio of receptive males to receptive female

females

When it comes to male and female reproductive strategies, which sex tends to invest more energy in a single mating opportunity?

Sexual dimorphism

difference in appearance between sexes

Intrasexual

competing within same sex for access to other sex

Intersexual

interactions between sexes, often females choosing which males to mate with

sexy sons effect

the fisherian runaway model is also known as ____

sexy sons effect

• Females indirectly benefit from choosing desirable males because their sons will have more matings

• Females receive no direct benefits and daughters receive no change in fecundity

good genes

• Females make fitter offspring— both sons AND daughters— by choosing to mate with males with an exaggerated signal

• Assumes costly for males to produce this signal

• Female preference for trait becomes more exaggerated over time

DIRECT BENEFITS MODEL

• Females develop preferences for male characteristics that provide material benefits

• Male characteristic does not have to be heritable

• Males that provide females with food or other resources demonstrate their ability to provide for offspring

SEXUAL CONFLICT

• Males evolve traits to manipulate female to their detriment

• Traits that enhance the fitness of one sex reduces fitness of another

direct benefits

Consider an animal in which males defend territories that have patchy food sources. When a female mates with the male, she gets access to this food source. Which type of intersexual selection model does this fall under?

overall genetic quality

Sexually selected traits should reflect the _____ of a mate

diet

More intense reds linked to better __

Bright white and crisp margins

_______ linked to better condition, dominance and/or breeding success

Long tails

_____ impose a cost and indicate a male is of good quality

behavioral traits

____ can be repeated often and are low- cost indicators of condition

DOMINANCE

• Females prefer dominant males and respond to signals that indicate dominance

• may also eavesdrop on male competition

male displays 

• Typically males display to females to persuade and stimulate

• Females remain coy to further assess male condition

Female receptive posture

when females are receptive, they signal to males

Males produce a lot of sperm in short reproductive cycles

Based on the property of anisogamy, which of the following is a prediction about male versus female mating strategies?

Intersexual selection

Which type of selection leads to elaborate male ornaments?

If they have the net effect of maximizing fitness

When will elaborate male traits persist in a species?

Traits that enhance the fitness of one sex can reduce fitness in another

Why would a male evolve traits to manipulate females?

they come from pigments obtained from the diet

Why are reds, oranges and yellows common colors to indicate condition and health?

they are considered higher quality

Why do females prefer to mate with dominant males?

It allows them more time to assess mate quality

In courtship, what is the benefit of females resisting male advances?