In conclusion, there are 3 scenarios that may lead to Polygyny: (1) Females have no other choice but...
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Transcript of In conclusion, there are 3 scenarios that may lead to Polygyny: (1) Females have no other choice but...
In conclusion, there are 3 scenarios that may lead to Polygyny:
(1) Females have no other choice but to mate with a mated male
(2) Females may be deceived
(3) Males control access to resources, but also Females may actively assess the consequences of their decisions and make an adaptive choice
....let’s examine this relationship between resources and females more closely in mammals....
Understanding variation in Mammalian mating systems is best understood in terms of what leads to a high or low POLYGYNY potential
E.g., Female reproductive success is limited by access to resources, thus the distribution of females depends on resource dispersion
(1) If females are clumped in space or predictable in time there is a higher POLYGYNY potential than if not clumped or predictable
(2) If males can defend a territory or access to females either directly or indirectly viacompetition for resource rich sites there is a higher POLYGYNY potential than if defense is not possible
A Comparative Survey of Mating Systems in Mammals
Even distribution of resources, little polygamy potential
Patchy distribution of resources, high polygamy potential
Females solitary and range defensible by males: In 60% of mammalian species the female is solitary and the male defends a territory that overlaps one or more female ranges
- If female ranges are small relative to the area a male can defend – polygyny - If female ................ large ............................................................ - monogamy
In the latter, usually the male deserts after mating, but in ~3% they stay to give parental care.
African wild dogs – coop. hunting, feedingKlipspringer - defense
Marmosetscarry young
Females solitary and range not defensible by males: Temporary, and wandering, association during estrus - monogamous
MooseOrangutan
Females social and range defensible by males:Can lead to permanent harem attached to male’s territory
Hanuman langurs
Colobus monkeys
Several males (often relatives) may defend larger groups more successfully and increase length of tenure of a harem
Females social, range not defensible,but Female movements are predictable:Males defend small ranges and wait for females to pass through on the way to predictable routes...
...on the way to the waterhole...
...or to richfeedinggrounds
Females social, range not defensible,Female movements not predictableMales follow females
Elephants – small female groups
Seasonal Harems
Seasonal estrus (predictability in time) – allows males to build up energy reserves for mating season and aggressively defend harems for the one month females are fertile.
Permanent Harems when females do not all come into estrus at the same time(unpredictability) –
solitary social
defensible range
non-defensible
small: Monolarge: Polygyny
Monogamy
Polygyny(harems)
Summary: in mammals, mating systems are determined from the complex relationshipsbetween female range size, movement, sociality, predictability in time and space, andthe male’s ability to defend a range
Polygyny of various sorts (including harems) depending on predictability of female movement and estrus
♀ = 5.0
♂ = 5.0
♀ = 6.7
♂ = 3.7
♂β = 3.0
♀ = 3.8
♀β = 3.8
♂ = 7.6
Lastly, multiple mating systems can occur withina single species, sometimes driven by environmentalcircumstances