BREEDING SYSTEMS AND REPRODUCTIVE STRATEGIES OF MAMMALS BREEDING

BREEDING SYSTEMS AND REPRODUCTIVE STRATEGIES OF MAMMALS

BREEDING SYSTEMS: COMPETING INTERESTS OF MALES AND FEMALES • Description of mating behavior and parental care by both sexes • Parental care & potential rate of reproduction of each sex

Reynolds. 1996. Animal Breeding Systems. TREE OSR = operational sex ratio = ratio of available adult females to males *Time budget for males = competition for mates and/or advertisement – *Females invest in gametes & care (lower rate & resource limits) –

BREEDING SYSTEMS: COMPETING INTERESTS OF MALES AND FEMALES • Are the result of a “battle” of competing interests between the sexes

COMMON TYPES OF BREEDING SYSTEMS IN MAMMALS

COMMON TYPES OF BREEDING SYSTEMS IN MAMMALS Polygamy

COMMON TYPES OF BREEDING SYSTEMS IN MAMMALS Polygamy • Polyandry = ? ? ?

COMMON TYPES OF BREEDING SYSTEMS IN MAMMALS Polygamy • Polygyny = • 2 types

COMMON TYPES OF BREEDING SYSTEMS IN MAMMALS Polygamy – Polygyny • Female (harem) defense

COMMON TYPES OF BREEDING SYSTEMS IN MAMMALS Polygamy – Polygyny • Male dominance

BREEDING SYSTEM AND DEVELOPMENT AT BIRTH • Lactation believed to precede evolution of parental care • Review of 500 placental species indicates: – Monogamy 1) large litters 2) altricial young 3) short gestation

BREEDING SYSTEM AND DEVELOPMENT AT BIRTH • Polygyny 1) small litters (<2) 2) precocial young 3) longer gestation 4) greater maternal investment before parturition

BREEDING SYSTEM AND SIZE OF MALES AND FEMALES • Monogamous • Polygynous

BREEDING SYSTEM AND JUVENILE DISPERSAL Natal Dispersal in Mammals is Male-Biased – – frequency & distance Females philopatric M F F Mom F M

BREEDING SYSTEM AND JUVENILE DISPERSAL The Inbreeding-Avoidance Model

BREEDING SYSTEM AND JUVENILE DISPERSAL Effects of Inbreeding on Mammals – inbreeding depression • decrease in fitness of offspring – Homozygosity • deleterious, recessive alleles