How do we explain parental care across different taxa?

Question 1

What is parental care?

Answer 1

Refers to the evolutionary behaviours associated with the investment placed into ones offspring

Question 2

What are the four parental systems seen across taxa?

Answer 2

Biparental, female only, male only and no care

Question 3

What is alloparenting?

Answer 3

Whereby a parent cares for another’s offspring

Question 4

How does alloparenting usually come about?

Answer 4

Brood parasitism - seen in birds - others lay in others nests and let mother rear - seen in 5-46% populations of Starlings (Petrie and Moller, 1991).

Question 5

What is egg dumping?

Answer 5

Female moves her egg to anothers nest - Cliff swallows are pros at this (Brown and Brown, 1988)

Question 6

What is at the bottom of the parental care spectrum?

Answer 6

No care - gamete release, seen in aquatic inverts (Starfish) and sponges

Question 7

What is the knowledge of evolutionary sex difference?

Answer 7

Males carry potential to father offspring at a faster rate than females can produce - expected to maximise number of matings.
Females invest more into zygote and therefore selective in mate choice
(Krebs and Davies, 1993)
Why is there parental care, surely males benefit from not providing care

Question 8

What two factors can we relate back to when looking at parental care strategy?

Answer 8

Animal history and life traits (physiological adaptations) and Ecological factors (environmental constraints) - trade off decisions

Question 9

What are the three explanations that are used in MY essay to explain parental care?

Answer 9

MATING SYSTEMS
FERTILISATION METHOD
PHYSIOLOGICAL ADAPTATIONS

Question 10

How do mating systems influence parental care?

Answer 10

Based on the influence it has on personal reproductive success and care needed for offspring

Question 11

What parental care and mating system do BIRDS USE

Answer 11

Biparental care and monogamous

90% have monogamous mating systems

Question 12

What parental care and mating system do MAMMALS USE?

Answer 12

Female only and polygynous

Question 13

What parental care and mating system do FISH USE?

Answer 13

Male only and polygamy

Question 14

What parental care and mating system do INVERTS use?

Answer 14

Limited care but female only if used and polyandry (hymenoptera)/polygamy

Question 15

What is reproductive success based on in birds?

Answer 15

Rate that food is brought to nest - two parents = twice as much food brought to nest, if either deserts have to invest time in searching for new nest and mate
Huge pressure on infant growth and endothermy

Question 16

What is an example of a successful monogamous system in birds?citation

Answer 16

Kittiwakes - monogamous life pairing system and biparental care - higher reproductive success if previous matings have occurred (Coulson, 1966)

Question 17

Which type of eaters(bird) is polygyny seen in abundantly?

Answer 17

Fruit and seed eaters when in season as in food is in abundance - male deserts and female cares
Male desertion only reduces productivity slightly - not too much effect

Question 18

What is the parental care/mating system in Yellow Rumped Caciques?citation

Answer 18

Female care and polygynous as females dont suffer from sharing a male - benefit from nesting close together and having his protection against predators (Robinson, 1986)

Question 19

What are the three reasons that polygyny is limited in birds and is the only reason monogamy is main system?
(Krebs and Davies, 1993)

Answer 19

1. Competition by males
2. Females suffer from lack of resources - affects his success
3. Aggression of other females

Question 20

What tradeoff does the polygyny threshold model explain?

Answer 20

Females have to choose to either
Accept a polygnous already mated male with a good territory but less parental care
OR
An unmated male with a terrible territory but full time parental care

Question 21

What bird species has been studied in regards to the polygyny threshold model?What was the outcome?

Answer 21

Great Reed Warbler choose polygynous male with the best territory - shows resource driven and then will adapt parental strategy
(Bensch and Hasselquist, 1992)

Question 22

What is deception in birds?

Answer 22

Means a female gets stuck with no help - male is polygynous and doesn’t return to her brood - DICK!

Question 23

What is the mating system and parental care in Florida Snail Kite? citation

Answer 23

Either sex can desert and depends on who has better chance of finding a mate, depends on operational sex ratio (breeding males: sexually receptive females)
Low (2015)

Question 24

Why does POLYANDRY occur in Jacana birds?

Answer 24

Resource defence polyandry - lays clutches in a defended area and males care for eggs - fixed clutch size so optimises her clutches
She’s brightly coloured and larger \
Jenni and Collier (1972)

Question 25

Why are females the main caregivers in mammals?

Answer 25

Female reproductive success depends on resources, therefore males will defend large territories (harems) in order to defend resources in a polygynous system - one male mates all.

Question 26

What is the two step process to explain reproductive success in male and female animals?

Answer 26

Krebs and Davies (1993) | Males will disperse based on female dispersion or compete for resources which will also influence female dispersion

Question 27

What are different mating systems in mammals based on?

Answer 27

Variation of female home range, group size and movements

Question 28

What normally occurs in mammal mating systems if movements of females are unpredictable

Answer 28

Temp harems if all synch up in oestrus Perm harems if separate oestrus cycles - defend large territory, exhausting so mate with all to optimise mating success (Le Boeuf, 1972) Red deers and Elephant seals

Question 29

In mammals what example shows that male care is based on defence? citation

Answer 29

Gorillas - non monogamous but male care because enhances their ability to mate with more females in group and father more young (Rosenbaum et al 2018)

Question 30

What is parental care based on in fish?

Answer 30

Guarding or fanning eggs - male | Mouthbrooding - keep eggs in mouth - catfish and cichlids- Helfman et al (1977)

Question 31

What fish species is monogamy seen in whereby males care?

Answer 31

Seahorses - pair bonds throughout season but can switch mates quite quick Mate guarding and male ends up with egg in pouch (Kvarnemo et al, 2000)

Question 32

Why does internal fertilisation and external fertilisation influence parental care?

Answer 32

Males can desert with internal fertilisation and be polygynous can't provide much care as female carrying offspring

Question 33

How does the order of gamete release in fish determine male care?

Answer 33

DAWKINS AND CARLISLES (1976) External fertilisation means that gamete structure plays a role Female can desert first as her eggs are laid and he has to wait for his sperm to settle - lighter

Question 34

What does order of gamete release not explain?

Answer 34

Can't explain males that create foam nests for female and deposit the sperm first - put down to it being in his territory - most aquatic inverts follow suit

Question 35

How does association with the embryo determine parental care in fish?

Answer 35

WILLIAMS (1975) Preadapts the sex to care Internal - live birth and protection External (most fish) - eggs laid in his territory - will defend and this attracts more females to lay here

Question 36

How does physiological adaptations influence parental care?

Answer 36

Evolved adaptations can predetermine a sex to care

Question 37

What's an example of an evolved adaptation in birds which could influence biparental care? citation

Answer 37

Both sexes have developed a crop in order to regurgitate food, pigeons create crop milk (Ehrlich et al, 2016)

Question 38

Whats an example of an evolved adaptation in mammals that influences female care?

Answer 38

Embryo development inside female and lactation to feed offspring

Question 39

Whats an example of an evolved adaptation in marsupials that influences female care?

Answer 39

Presence of pouch to carry young

Question 40

Whats an example of evolved adaptation in reptiles that influences the lack of care?

Answer 40

Self-sufficient offspring - can regulate body temp and forage themselves.

Question 41

What are your conclusions?

Answer 41

Parental care is difficult to generalise when looking at mating systems - many exceptions and mating systems change in accordance to ecological constraints (polygynous threshold model) Fertilisation method is useful for explaining which sex can desert first Better to look at individual species and ecological constraints/life history - major impact e.g. predation, female, food, clutch size