1. Parental Care

2. So far … Mates have been secured Rules of the particular mating system have been exercised Offspring to care for What are the behavioural and evolutionary rules for raising offspring?

3. Relationship between mating systems and parenting 1. Monogamy - both male and female participate in rearing e.g. trumpeter swan

4. Relationship between mating systems and parenting 2. Polygyny - one male, several females - usually the female provides care

5. Relationship between mating systems and parenting 3. Polyandry - one female, several males - usually the male provides care -Wilson’s phalarope

6. Relationship between mating systems and parenting 3. Polygynandry - promiscuous - either sex could provide parental care

7. Relationship between mating systems and parenting Phylogenetically Gross and Sargeant ‘85 - Survey of Teleost fish Teleosts 79% - no parental care 21% parental care Two parents >75% One parent <25% Internal fertilizerExternal fertilizer 86% female14% male30% female70% male

8. What governs which sex should invest? 1. Anisogamy - female has already made greater investment 2. Confidence in parentage -species with internal fertilization -male should be inclined to desert -female should be inclined to care 3. Association with embryo - sex most closely associated with embryo should offer care

9. Parental investment Any investment in an offspring that increases its chances of survival and reproduction at the expense of the parents’ ability to invest in other offspring

10. Parental investment Temporal component Cumulative investment TerritoryMating /egg laying IncubationFeedingFledging MALE FEMALE

11. Parental investment Temptation to desert Cumulative investment TerritoryMating /egg laying IncubationFeedingFledging MALE FEMALE

12. Parental investment Any investment in an offspring that increases its chances of survival and reproduction at the expense of the parents’ ability to invest in other offspring

13. Parental investment Rhesus monkeys % time in contact Weeks 102030 % time rejected

14. Parental investment Budgies Log feeding rate Offspring weight

15. Parental investment Budgies Begging Rate Female alone With male

16. Parent offspring conflict At some point, the parent-offspring relationship is terminated Why and who determines this?

17. Parent offspring conflict Trivers - looked at benefit/cost ratio to parent Benefit: Gain in survivorship from investing in offspring Cost: Inability to invest in other offspring

18. Parent offspring conflict Trivers 5 4 3 2 1 0.5 0.25 B/C ratio Time P O P O Time of conflict

19. Parent offspring conflict Conflict during infancy Benefit or Cost Level of Parental Investment 1/2 Cost Maximum benefit for offspring Maximum reproductive success for parent

20. Sibling rivalry Corollary of parent/offspring investment -any offspring more interested in its own survival more than in its siblings’ survival - if any siblings benefit:cost ratio is <0.5 - conflict r siblings = 0.5

21. Sibling rivalry Mock and Parker (1997) -HIERARCHY MODEL Total amount of food brought by parents

22. Sibling rivalry Does this model explain observations on sibling rivalry? Cattle egrets

23. Sibling rivalry Does this model explain observations on sibling rivalry? Cattle egrets EarlyMidLate % share

24. Sibling rivalry Great Blue Heron Weight at day 14 1,2 3Lost sib 4 No loss 5 Chick number

25. Parent Offspring Conflict in Utero Haig (‘93) -mother - selected to limit nutrient transfer - fetus - selected to increase nutrient transfer

26. Parent Offspring Conflict in Utero Haig (‘93) Fetal cells migrate to endometrium Fetal cells make constriction of arteries more difficult Benefits to fetus a. hormone release into female’s blood b. nutrients under fetal control