Parental Care

Question 1

What is parental care?

Answer 1

Any behaviour on the part of the parent that appears likely to increase the survival and fitness of offspring.

Question 2

Parental Effort

Answer 2

Expenditure of parental resources spent on parental care of one or more offspring.

Question 3

Parental Investment

Answer 3

Any action on the part of a parent that increases the fitness of its offspring at a cost to any component of the parent’s fitness.

Question 4

Benefits of Care

Answer 4

Increased survival and reproduction (fitness) of offspring.

Question 5

Costs of Care

Answer 5

• Decreased survival (more likely to die from predation while caring for young)
• Decreased opportunities to feed (especially for mouth-brooders, who lose a lot of weight while caring for young)
• Decreased future mating opportunities

Question 6

Care evolves if…

Answer 6

The benefits of care outweigh the costs of care.

Question 7

Forms of Care

Answer 7

• Pre-fertilization investment (prepping nests / territories, nuptial gifts / courtship feeding, egg production)
• Investment between fertilization and hatching (guarding eggs outside or inside the body, incubation or internal gestation, provisioning food before birth)
• Provisioning after birth (young eat food collected by parents)
• Care for nutritionally independent young (parental protection – suppressing daughter’s competitors)

Question 8

Egg Size and Fecundity

Answer 8

In harsher environments, it is better to make bigger and stronger eggs.
In benign environments, egg amount can be favoured with minimal consequences.

Question 9

Sex of Caregiver

Answer 9

No Care – common among insects
Female-only care: common among mammals
Male-only care: common among fish (when there is care)
Biparental care: common among birds

Question 10

Hypotheses about Sex of Caregiver

Answer 10

Incorrect hypotheses – Paternity Certainty, Order of Gamete Release
Correct (for now) – Association Hypothesis: preadapted to providing parental care if already associated with eggs strongly. ie. internal fertilizers already hold them inside, so they’re associated, and cost of providing care is minimal. externally, males hold territories to attract females. once associated with a territory, they’re already protecting it, so caring for eggs on that territory is minimal effort.

Question 11

Expenditure Changes with Benefits of Care are based on… (three things)

Answer 11

Offspring quantity (Bluegill sunfish parental investment increases with brood size)
Offspring quality (Striped kribensis fish cared more for well fed young than poorly fed young)
Relatedness (Bluegill sunfish parental investment decreases with paternity uncertainty)