L7 - Parental Care Flashcards
Name 7 environmental hazards for offspring
- Predation
- Hypoxia
- Temperature
- Food shortages
- Parasites
- Pathogens
- Desiccation
What is parental care?
Behaviour that increases fitness of offspring (and is likely to have originated/maintained for this function)
What is parental investment?
Behaviour that increases offspring fitness at the cost of a parent’s ability to reproduce in the future
What are the 7 types of parental care?
- Provisioning of gametes
- Oviposition site selection
- Nest building and burrowing
- Egg/ offspring attendance
- Egg/ offspring brooding
- Food provisioning
- Care after nutritional dependence
What is provisioning of gametes?
Provisioning of energy and nutrients (e.g. proteins and lipids)
What advantage do larger eggs give?
Offspring have greater nutrient reserves at hatching
In some insects, what do females do after birthing eggs?
Coat eggs with defensive secretions
What is oviposition
The act or process of depositing or laying eggs, especially by means of an ovipositor (tube-like organ used to lay eggs in specific places)
What is oviposition site selection?
Non-random egg laying site
Give examples of oviposition site selection
Birds’ nests, choice of spawning site in fish and amphibians (external fertilisers)
Give examples of materials used to build nests
Mud, plant material, silk, mucus
What are three possible reasons for a parent to stay attending to egg/ offspring?
Protection from predators, fanning, site maintenance
What site maintenance does the male African bullfrog do?
Will dig channels between bodies of water to make sure the eggs do not dry out, prevent desiccation
What is egg/ offspring brooding?
Carrying the eggs or offspring - a mobile form of egg/ offspring attendance
Describe different examples of food provision
Parents alert offspring to food location
Regurgitation of food
Provision of actual food
Production of specialised food source e.g milk
Matriphagy - when offspring eat mother
What are two examples of care after nutritional independence?
- Winter flocks of Bewick’s swans: parents assist offspring in competition for food
- Burying beetles: larvae nutritionally independent at 72 hours, females remain with offspring for 48 more
Name and describer the three levels of care needed by offspring?
- Superprecocial: capable of independent
living soon after birth - Precocial: relatively mature / mobile at birth/hatching
- Altricial: young immature at
birth/hatching
What are the costs to parental care?
- Increased predation risk (e.g. male pipefish more conspicuous)
- Physiological costs: male cotton top tamarin can lose about 11% of body mass in 3 months following birth
- Cost of raising a child in the UK is >£225K
What are the benefits of parental care?
- Improved offspring survival
- Improved offspring quality
Why do the costs and benefits of parental care differ between species?
Ecology
What factors can help explain the diversity in parental care?
- Parental care can differ between sexes
- Ecological factors (relationship between species and environment)
Name and describe the 3 types of “parental who cares”
- Maternal care: care provided by female
- Paternal care: care provided by male
- Bi-parental care: care provided by both parents
Name and describe the 4 types of mating systems
- Monogamy: Male & female form pair bond (can be short-term or long-term)
- Polygyny: Male mates with several females; females mate with a single male
- Polyandry: Female mates with multiple males
- Promiscuity: Both male and female mate several times with different individuals (also polygamy)
What type of parental care (i.e who the carer is) is each mating system associated with?
Monogamy = bi-parental care
Polygyny = maternal care
Polyandry = paternal
What is oviparous?
Producing young by means of eggs which are hatched after they have been laid by the parent e.g as in birds.
Give examples of parental care for birds
Nest building, incubating eggs, predator defence of eggs and chicks, feeding chicks
What percentage of birds have bi-parental, maternal, paternal care?
90% bi-parental, 8% maternal, 2% paternal
Which category do the majority of bird chicks fall into:
- Superprecocial
- Precocial
- Altricial
Altricial
What is argued to be the primitive form of bird parental care? Give two pieces of evidence
Paternal
- Fossil record
- Primitive birds have paternal care
Which sex always provides care in mammals?
Females
Describe monotremes and marsupials. Give an example
- Monotremes: egg incubation in an abdominal pouch, no nipples e.g platypus
- Marsupials: altricial young cared for in a pouch e.g kangaroo
In what percentage of mammal species do the males assist with parental care
Around 10%
What type of parental care do the majority of fish have?
No parental care
What is more common in fish - paternal or maternal care?
Paternal
What does natural selection favour?
Favours the evolution of behaviour that will maximize lifetime reproductive success
How does parental investment explain why it is normally females providing parental care?
Sex that invests less in gametes and embryos is less concerned about what happens to offspring after mating
How does paternity certainty explain why it is normally females providing parental care?
Males are less sure than females that the offspring is theirs
What theory explain the fact that paternal care is more common in fish?
The Association theory
What is the desertion opportunity theory?
Whichever parent has the opportunity to desert the offspring first will.
What is the association theory?
- Association with embryos preadapts a sex for parental care
- Internal fertilisers: female association with embryo > embryo retention and live birth > maternal care
- External fertilisers: eggs laid in male’s territory > defence of territory > defence of eggs and young
Give an example of paternity certainty affecting parental care
Bluegill sunfish:
- have sneaker male phenotypes
- sneaker males look like females and use this to fertilise eggs without the male, who’s territory the eggs are in
- when a sneaker male is placed next to male’s territory the original male gives less parental care
What drives maternal care?
- Internal fertilisation gives male opportunity to desert
- Sexual selection/parental investment: male gains more by deserting: his Lifetime Reproductive Success depends more on number of matings
What drives biparental care?
- Constraints on offspring survival (predation, harsh environment etc)
- If offspring survival is low when only one parent cares this can drive the evolution of biparental care
- Can be simultaneous or sequential care
- Linked to sexual selection: parents cooperate more when sexual selection is not intense and sex ratio is not skewed
What is brood parasitism?
- Forced adoption
- Parasite lays eggs in host’s nest and offspring are cared for by host parent(s)
- Famous examples in birds (~1% of birds) but also occurs in other taxa (insects, fish)
What bird its adoption most common and in what percentage of them does it occur?
Common Eider - 47%
