Mating systems

anisogamy

gametes are different sizes for males and females

female goal in mating

good male with good resources

male goal in mating

produce as much offspring as possible

EPP

environmental potential for polygamy; extent to which mates can be defended and monopolized

when is EPP high?

when resources (thereby females) are clumped together

polygyny

male mating with multiple females

types of polygyny

resource defence, female defence, lek

resource defence polygyny

males defend resources that females want, e.g. damselflies defending egg laying spots

female defence polygyny

males defend females and create harems, more likely if females are gregarious, e.g. elephant seals

leks

small male display territories, basically dance floors

lek polygyny

males attract females via leks

monogamy pros/cons

enhanced direct fitness for both parents but demands parental care

polyandry

female mates with multiple males, gives her the opportunity to desert

cooperative polyandry

females have multiple male mates and they all raise a single brood together on one territory

why does cooperative polyandry happen?

low number of females in the population