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 Assumes 1.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 Toward males 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 Mating rate Lek size 10 0

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 Polygamous 1.Polygyny a. Female Defence Polygyny b. Resource Defence Polygyny c. Lek Polygyny d. Scramble Competition Male controls access to 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 %

Kinds of mating systems Are mating systems ‘ fixed ’ ? - do all members of a species conform to one mating system How monogamous is monogamy? !Kung % Yanomama - 9% U.S % Humans

Summary Mating Systems Monogamous 1. Mate assistance hypothesis 2. Mate guarding hypothesis 3. Female-enforced monogamy Polygamous 1.Polygyny a. Female Defence Polygyny b. Resource Defence Polygyny c. Lek Polygyny d. Scramble Competition 2. Polyandry a. Sperm replenishment b. Prostitution c. Resource Defence d. Lek