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Mating Systems
Mating System
Species typical pattern of mate-finding, reproduction and parenting of offspring
Kinds of mating systems
Polyandry
Polygyny
Polygynandry
Monogamy
Number of females
Number of males
Polygamous
Kinds of mating systems
Monogamous Mating Systems
-a mating system in which one male and one female for and mate with only each other during a given breeding season
To put it another way-neither sex is able to monopolize more
than one member of the opposite sex
Kinds of mating systems
Monogamous Mating Systems
First question - why should a male be monogamous?
If the particular niche dictates that a male will do better reproductively staying with one mate - will do so.
-mates are scarce-resources are scarce or non-defendable
Kinds of mating systems
Monogamous Mating Systems
1. Mate assistance hypothesis
-male stays with one female because it is to his advantage to help raise offspring
Hippocampus whitei
-male carries offspring-brood pouch contains 1 clutch
-no point to new matings
Kinds of mating systems
Monogamous Mating Systems
2. Mate guarding hypothesis
-male spends time with mate to ensure fertilization
Assumes1. Females are scarce (highly male-biased OSR)2. Females will mate multiply
Hymenocera elegans-male stays with female for weeks-female receptive every 3 weeks
Kinds of mating systems
Monogamous Mating Systems
3. Female-enforced monogamy-female blocks polygamous moves by mate
Icteria virens (yellow-breasted chat) - aggression by females
0
More aggressive
Less aggressive
Toward Toward Towardmales females wrens
Kinds of mating systems
Polygamous Mating Systems
1. Polygyny - males mate with several females
a. Female Defense Polygyny
-females live in permanent groups that males defend
Male
Kinds of mating systems
Polygamous Mating Systems
1. Polygyny - male mate with several females
b. Resource Defence Polygyny- males defend resource females need
Lamprologus -males gather and defend oviposition sites - mollusc shells
Kinds of mating systems
Polygamous Mating Systems
1. Polygyny - male mate with several females
c. Lek Polygyny- males compete for high rank
Kinds of mating systems
Polygamous Mating Systems
1. Polygyny - male mate with several females
c. Lek Polygyny- males compete for high rank
Upper limit on lek effectiveness
Matingrate
Lek size100
Kinds of mating systems
Polygamous Mating Systems
1. Polygyny - male mate with several females
d. Scramble competition
-females are available for a short period-males mate with as many as possible
Kinds of mating systems
Polygamous Mating Systems
Polygamous1. Polygyny
a. Female Defence Polygyny
b. Resource Defence Polygyny
c. Lek Polygyny
d. Scramble Competition
Male controls accessto resources
Male can’t control access to resources
Kinds of mating systems
Polygamous Mating Systems
2. Polyandry - one female mates with several males
Male territories
Female territory
Jacana
Kinds of mating systems
Polygamous Mating Systems
2. Polyandry - one female mates with several males
Kinds of Polyandry
1. Sperm replenishment
e.g. Drosophila
-females mate multiply to get extra sperm
# of eggs
Time
1 mate Multiple mates
Kinds of mating systems
Polygamous Mating Systems
2. Polyandry - one female mates with several males
Kinds of Polyandry
1. Sperm replenishment
2. Prostitution - females mate with males to get access to resources
3. Resource Defense - females control access to resources
4. Lek Polyandry - females compete for dominance - some primate troops
Kinds of mating systems
Polygamous Mating Systems
2. Polyandry - one female mates with several males
Benefits of Polyandry
1. Sperm replenishment- add to a depleted supply of sperm- avoid cost of storage
2. Material benefits
3. Genetic benefits-replace ‘inferior’ sperm- increase genetic variance in offspring
4. Convenience- avoid cost of fending off copulatory attempts
Kinds of mating systems
Are mating systems ‘fixed’?- do all members of a species conform to one mating system
How monogamous is monogamy?
Indigo bunting
Days before egglaying
12 0
Extra-pair
Within pair
Kinds of mating systems
Are mating systems ‘fixed’?- do all members of a species conform to one mating system
How monogamous is monogamy?
Indigo bunting
Rate of extra pair copulation - 27 - 76%
Kinds of mating systems
Are mating systems ‘fixed’?- do all members of a species conform to one mating system
How monogamous is monogamy?
!Kung - 2 - 3%Yanomama - 9%
U.S.-10 - 18%
Humans
Summary
Mating Systems
Monogamous1. Mate assistance hypothesis
2. Mate guarding hypothesis3. Female-enforced monogamy
Polygamous1. Polygyny
a. Female Defence Polygynyb. Resource Defence Polygynyc. Lek Polygynyd. Scramble Competition
2. Polyandry
a. Sperm replenishmentb. Prostitutionc. Resource Defenced. Lek
