Animal Mating Systems: Monogamy, Polygamy & Brood Parasitism

• Mating systems involve mating associations.

Mating/Breeding Systems

• Monogamy is a one-to-one mating system.
• Polygamy is a one-to-many mating system.
• Polyandry is when one female mates with many males.
• Polygyny is when one male mates with many females.
• Polygynandry is a many-to-many mating system with a network of preferences, and is sometimes described as some-to-some mating.
• Polybrachygamy is promiscuity where there is a true many-to-many mating.

Brood Parasitism

• Brood parasitism is the opposite of all other mating systems because at least with the obligate system, the female forgoes any maternal care formally.
• Brood parasites do not build a nest or provide parental care.
• An example of brood parasite is the cuckoo
• Brood parasitism can be inter-specific or intra-specific

Polygamy

• Polygyny is where one male mates with and controls access to many females
• Polygyny is the most common form of polygamy
• Polygyny types are:
• Resource-defense
• Female-defense
• Male-dominance: females are choosing.
• Scramble: males searching for mates without competition

Polyandry

• Polyandry is where one female mates with and controls access to many males
• Polyandry is an uncommon system
• Polyandry is often combined with male polygyny or as an alternative to monogamy
• Seen in some social canids
• Polyandry is associated with sex role reversals, with males doing most of the parental care
• Polyandry types are:
• Resource-defence
• Female-access

Polyandry Examples

• Polyandry is more common in birds such as:
• Hummingbirds
• Spotted sandpipers
• Galápagos hawk
• Phalaropes
• Jacanas
• Rheas
• Examples of mammals that mate with polyandry:
• "New World" monkeys
• African Wild Dog

Polygynandry and Promiscuity

• In both polygynandry and promiscuity, males and females have multiple mates
• Polygynandry is non-random choice and pairing of males and females
• This means polygynous males mate with polyandrous females
• Chimpanzees are an example
• Promiscuity (polybrachygamy) involves a random choice and pairing of males and females
• Can be found in both sexes that have multiple partners
• Chimpanzees, many "monogamous" primates (e.g., gibbons, siamangs, tarsiers) may actually fit this system better

Alternative Mating Strategies

• Alternative mating strategies are used when males are unsuccessful at getting access to a mate
• Occurs in monogamous or polygynous species
• Forced matings or copulations (rapes)
• This is common in birds such as Mallard ducks
• Surreptitious matings or kleptogamy (sneak mating)
• Mimicry (of females) in male bluegill sunfish
• Bullfrogs: satellite positions and croaking
• Opportunistic beta or defeated individuals such asDeer, wolves, take advantage of distracted males

Types of Monogamy

• Genetic monogamy refers to the DNA analysis used to confirm the mating/pair bond between a male and female
• Sexual or mating monogamy is an exclusive male-female relationship based on sexual interactions
• Social monogamy is social living arrangement between a male and a female
• Coyotes

Definitions of Monogamy

• A monogamous social system refers to social monogamy
• A monogamous mating system refers to monogamous sexual and genetic relationships

Monogamy Criteria

• Seven types of monogamy criteria include:
• Reduced sexual dimorphism
• Exclusivity of mating
• Pair bond
• Biparental care (i.e., paternal care)
• Exclusion of strangers (non-kin) from the family
• Reproductive suppression
• Incest avoidance

Sexual Selection

• Reduced sexual dimorphism and reproductive variance:

Exclusivity of Mating

• Exclusivity of mating means the number of (sexual) partners in time
• Exclusivity applies to copulation & paternity
• Temporal dimension:
• Simultaneously: Exclusivity factor (unfaithfulness vs. faithfulness)
• Serially: Serial monogamy
• Biological measures:
• Genetic markers (if inheritance pattern known)
• Protein electrophoresis (exclusive method)
• DNA fingerprinting (expensive)

Pair Bonds

• Pair bonds relate to the nature of the association and interaction(s)
• Spatial proximity (shared territory / home range)
• Joint nesting, denning
• Shared home range
• Joint travel
• Frequency: continuous or discreet associations
• Duration: length of the pair bond
• Ranges from copulatory-restricted bond (gibbons) to "superfaithfulness" (geese)

Biparental Care

• Male/female involvement and investment (time and energy) is high and often equal
• Sometimes alloparental care (cooperative breeding); Continuum:
• Helpers (facultative; one sex [females only]) to
• Extended, multigenerational, permanent families

Other Criteria of Mating

• Exclusion of strangers from the family: non-kin are rarely tolerated
• Fits with kin selection theory
• Immediate family or extended family systems
• Reproductive suppression of non-breeding individuals or subordinates (when a dominance hierarchy exists)
• Non-breeders are usually helpers
• Incest avoidance: does not apply to all species, but the "incest taboo" is often observed

Monogamy vs. Polygamy

• About 90% of birds are monogamous
• Genetic monogamy is less than 25%
• Only 4% of mammals are monogamous
• Most species with paternal care are monogamous although paternal care is also found in polygynous species such as zebras and Indian langurs
• Monogamy is more likely to be observed when resources are scattered or shelter/nest sites are scarce

Definition of Monogamy

• Monogamy is a “preference” for a specific mate per Sue Carter.
• Many monogamous species have indiscretions ("infidelities")
• Gibbons, wolves, voles
• Gallivanting (Barash, 1981) or extrapair copulations are common in males as well as females
• Many species are actually “opportunistically polygamous” (as opposed to strictly monogamous or promiscuous)
• Important factor is mate “monopolization” or control

Mammal Monogamy Taxonomy

• Two types of Monogamy:
• Facultative means paternal investment is low (sometimes absent), loose association, occasional polygyny
• Obligate means cohesive, paternal care, extrapair mating very rare, occasional polyandry
• Group size of mammals:
• Solitary: 1
• Pair: 2
• Temporary Family: 3-6
• Permanent nuclear family: SA 4 SA
• Permanent extended family: SA >6 SA

Continued Mammal Monogamy Taxonomy

• Dimension 1 (spatial): Territorial, Female-defence, Dominance-based
• Dimension 2 (temporal): Serial, Permanent

Taxonomy of Vertebrate Mating Organizations

Mammal Monogamy Types

• Grade I: male and female defend common territory but offspring leave after weaning
• Red foxes, elephant shrews, tree shrews, klipspringer
• Grade II: adults are permanently paired but the dispersion of the young is delayed
• Coyotes, beaver, some marmots
• Grade III: rank-determined monogamy (multi-male/multi-female groups)
• Callitrichids, wolves, African wild dogs, dholes.

Canid Social and Mating Systems Taxonomy

• In the Fox 1975 taxonomy, Dhole "exemplifies a further evolution of canid social behavior, where the term "clan" is appropriate for such a large group sharing the same range but rarely hunting together" and "It therefore constitutes a Type IV canid social class, the clan (analogous to the baboon troop)"
• Species/genera for the classes:

Canids: Emergent Social and Reproductive Characteristics

• Monogamy
• Parental care is paternal care
• Alloparental care ranges from occasional helpers to true cooperative breeding
• Family systems:
• Immediate or nuclear family refers to Foxes, Coyotes
• Extended family refers to Wolves, African Wild Dogs
• Congregation of families (clan system) refers to Dholes

Characteristics with Siblings

• From mating system to social system: Temperament and relationships with siblings

Overview of Mammal Monogamy

• Monogamy in mammals:
• Marsupialia (marsupials): a few species
• Macroscelidae (elephant shrews): a few species
• Chiroptera (bats): false vampire bats
• Lagomorpha: hares, rabbits, pikas: a few species
• Rodentia (rodents): Sciuromorphs (squirrel-like): Castoridae (beavers)
• Myomorphs (mouse-like): Some voles & mice, gerbils, spiny mice.
• Hystricomorphs (porcupine-like): ?
• Myomorpha examples:
• 55 Peromyscus deer mice species
• 2 species common in the Maritimes
• 2 are monogamous in the genus
• 67 Microtus common vole species
• 2 species in the Maritimes
• 2 are monogamous in the genus
• Mammals monogamy pt. 2:
• Cetacea (whales, porpoises, dolphins): a few species
• Perissodactyla (odd-toed ungulates) such as rhinoceros, horse, ass, zebra: a few species
• Artiodactyla (even-toed ungulates) such as pigs, hippopotamus, deer, gazelles, buffalo, sheep, goats, etc.: a few species
• Carnivora (carnivores): Canidae: most species (except: raccoon dog & some South American canids)
• Viverridae (civets, genets, mongooses, etc.): dwarf mongooses
• Hyenidae (hyenas): brown hyenas, aardwolves
• Mammal monogamy pt. 3:
• Primates:
• Apes: none
• Lesser apes: Hylobatidae (gibbons and siamangs), although minimal paternal care.
• Monkeys:
• Callitrichids (marmosets and tamarins)
• Titi monkey (genus Callicebus)
• Night or owl monkey (genus Aotus)

Bird Classification and Monogamy

• Bird classification:
• AVES
• NEOGNATHAE
• GALLOANSERES - Galliformes - Anseriformes
• NEOAVES
• PALEOGNATHAE (ratites)
• Monogamy in birds
• At least “mating monogamy” is believe to be about 90% of bird species.
• Genetic monogamy may just be at 25% of species
• Paternal care in bird species is 70%
  • Usually associated with biparental care
• Monogamy in birds can be:
• Serial or seasonal
• Perennial or long-term

Anseriformes Mating Systems

• Polygyny: Magpie goose, maybe opportunistically Likely to occur in captivity, especially if the sex ratio favours it (harem polygamy)
• Promiscuity: Maccoa / Musk / African Comb / Muscovy ducks; Black swan.
• Forced extra-pair copulation or FEPC (a “mixed” reproductive system): Dabbling ducks, pochards, stiff tails
• Monogamy: 3 sub-types:
• Perennial (long-term): Mostly swans and geese
• Mate fidelity 92-100% of the time by Black, 1996
• Seasonal or annual without re-pairing: Dabbling ducks and pochards
• Seasonal or annual with re-pairing: Rare, found in shelducks and seaducks
• Taxonomic systems of Anseriformes:

• Approximately 93% of anatids are monogamous
• Approximately 7% are polygynous/promiscuous
• Very little to no polyandry in Anseriformes, there is a very homogenous group, like Canids & Callitrichids

Paradox of Anseriformes

• Anseriformes should be polygynous based on known correlations with other bird groups
• The young are highly precocial and imprint. Same in Galliformes but those are all polygamous
• There is no temporal/spatial contiguity with the breeding areas: they pair way before mating, far away from the breeding grounds
• They are the only bird taxon where females are more philopatric than males, meaning they are very faithful to natal areas

Details of Non-Monogamy

• Anseranatidae or Magpie geese are Trios (polygynandy): one male, two females, and "cooperative breeding" with combined brood
• Grey-sided comb ducks are Polygynous harems
• Ruddy ducks involve a mixture of monogamy / polygyny / promiscuity
• Maccoa ducks are Polygynous
• Musk ducks and Muscovy ducks have Promiscuity

Characteristics of Perennial Monogamy

• It may be associated with "super-faithfulness" (term used by Lorenz)
• It is common in geese and swans: mate fidelity ranges from 92-100% of the time
• At migration time, geese and swans are not fully grown
• The young often stay in the group of the parents
• Geese and swans are larger than ducks, so males can actually matter against predators at nest sites in perennial monogamy
• Instead, Ducks have solitary and cryptic females
• Strategy is completely different
• Female ducks are also more likely to conceal their nests

Examples of Divorce in Perennial Monogamy

• Barnacle geese:
• Approximately 40% have more than one partner in their life (1-4 mates)
• Pair bond duration: +/- 4.70 years
• Some together for 10+ years, up to 19 years
• Annual divorce rate: less than 2%
• Greylag geese:
  • Annual divorce rate 10.5%
  • Almost 30% of pairs eventually divorce

Population Definitions

• Group: any social unit in gregarious/social mammals and birds (pack / troop/band / herd for primates, pride for lions, etc)
• Mated pair + dependent offspring IS NOT social group
• Rather, a "family"
• Extended Families - Wolves, dholes, marmosets, tamarins, are social groups
• Composed of more than 2 generations, and usually referred to as “cooperative breeder”
• Population is a group of organisms of the same species in a certain place

Models of Population Groups

• Wynne-Edwards "group selection" model
• Selye's model: general adaptation syndrome (GAS)
• Calhoun's data on overpopulation
• Christian's model of population regulation
• Sapolsky's data on dominance / subordinance

Demographic Regulations

• Regulation is regulated by external or internal factors

Intrinsic factors:

• Behavioral mechanisms (Wynne-Edwards, Calhoun)
• Physiological mechanisms (Selye, Christian, Sapolsky)
• Reproductive strategies are also relevant
• The r/K dichotomy is actually a continuum

Reproductive Strategies

• Reptiles, birds, and mammals are K selected (mice, etc).
• Amphibians are generally r selected (some salamanders, etc.)
• Fish species have a large range within r and K selection
• Pipefish/Seahorse are strongly K
• Killfish/Minnows Are strongly R

Environmental Conditions and Population Size

• Density-independent:
• Climate, food, fire floods, etc
• Some can be dependent to population density
• Cause fluctuations
• More dominant in R selected
• Density-dependent:
• Competition,parasitism, disease, etc
  • Affect K selected

Regulation Timing

• Mechanisms affect “timing”
• Suppressive/Inhibitory Mechanisms occurs in groups and populations
• Behavior: Inhibition/Suppression
• Physiological: Inhibition/Suppression
• Can also use Temporal Variables:
• Pre-conception: Psychological
  • Castration for males/Contraception for females -Post-conception: Also psychological in women
• Ex: Abortion

Variable Breakdown

Self Regulation

• Competition/self regulation include (mal) adaptivity to constraints