NCSU Course ZO410 Lecture:
Mating Systems
Mating strategies:
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Result from anisogamy and Bateman gradient: different reproductive
success of M and F
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Species can use different "strategies", sometimes two strategies in same
species. when results in one strategy/mating system, = ecologically stable
strategy (ESS)
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Bluegill example
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defined by:
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how many individuals M or F mates with
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whether pair bond forms
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how long pair bond maintained
Mating systems
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Monogamy= male and female mate with one partner (per life or breeding
season)
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Four reasons:
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F's scarce
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M essential to offspring survival
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Cost of polygyny too high
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F aggression
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Compromise for M, best for F
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Polygyny= males control access to more than one female
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Resource defense - indirect control of female by controlling resource
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Female defense - direct control, females often grouped
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both= classical territory
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expected when differences in quality of territories
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Three reasons:
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average reproductive success of all increases
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F sacrifices immediate fitness for long-term survival
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F's prefer to mate in colony rather than with peripheral M
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in mammals: F's less mobile, herded by M's, etc.
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M strategy benefits from all types of polygyny, F compromises
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Polyandry = females access more than one male
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sex-role reversal in many
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fish, bird examples
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Promiscuity = males and/or females mate with more than one partner,
no long-term relationship
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Overlap Promiscuity
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Lek Promiscuity
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M display to attract F (mating-only territory), F chooses best
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hammerhead bat example
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Hierarchial Promiscuity
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M strategy benefits from promiscuity, F uses "He-man Strategy"
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Polygynandry = rare!
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Acorn Woodpeckers, sisters/brothers mate
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Galapagos hawks
Mating systems are a potential, not determined
Dunnock example
Human Mating Systems
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Most individuals monogamous, most societies polygynous
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extra-marital affairs more common in M than F
Polygynous Society Characteristics:
1) only wealthy men have means to acquire multiple wives
2) co-wives compete
3) co-wives often in separate households
4) extreme forms more frequent as agriculture advanced
Polyandrous Societies:
1) Tre-bas in Tibet
- to prevent large plots of family land from being
divided among sons= share one wife
2) Pahari in northern India
-generally 2 husbands, 2 wives, share everything
No matriarchal societies where F's control resources
Original author this subsite (lmat.html)= calswww@ncsu.edu, originally
posted 7-95 under direction of Dr. John G. Vandenbergh. Updated 7-22-98
forJGV by J. Kemper.