Reproductive and parental behaviour

Question 1

How do “investments” of each sex differ wrt reproduction?

Answer 1

• Both sexes want max reproductive success for minimum effort
• Assymmetry in initial investment
  > Large, costly eggs, all fertilised by one mating, high investment in each offspring
  > Small cheap sperm, fertilise eggs faster than they become available in one female -> multiple matings necessary, no need for high investment in each offspring

Question 2

Why is there a conflict in optimal mating strategies?

Answer 2

Females - mate once and get help raising osspring

Males - mate with as many females as possible and move on after each mating

Question 3

How does the mating strategy of a species affect captive breeding?

Answer 3

Understand natural mating systems of the species to give best reproductive success

Question 4

How many mammals are socially monogamous? Birds?

Answer 4

Mammals 3%

Birds 90%

Question 5

Are socially monogamous species actually monogamous?

Answer 5

Rarely according to genes (90% unfaithful)

Question 6

Give examples of genetically monogamous zoo species

Answer 6

Elephant shrews

Gibbons

Question 7

What is required before mating?

Answer 7

Courtship - males demonstrate their high quality
> social experience during development
eg. Australian boards kept separately after weaning- v sexual performance (courting behaviour, no. copulations, time ejaculating, 50% had abnormal sperm!) [Hemsworth 1977/8]
> opportunity for courtship
eg. Hanging flies - larger the nuptial gift (prey), longer the mating session [Barnard 2004]

Question 8

Give an example of poorly self sustainable captive species

Answer 8

Giant panda

• few breed naturally
• males show no interest towards females in heat or are aggressive towards them

Question 9

Give a study looking at characteristics of husbandry and management associated with normal breeding behaviour in giant pandas

Answer 9

Powell 2002
- 11 captive males in 3 chineses facilities
- survey of housing/husbandry
- questionnaire of frequency and intensity of courtship/breeding behaviours in ONE breeding season
> males housed with climbing facilities and cover from the public
> opportunity to investigate odours of other pandas pre-breeding season
> interaction with females through metal barrier before breeding season
> keepers have good relationship so that touch/interaction does not cause stress around breeding season

Question 10

Give two definitions of parental behaviour

Answer 10

Rosenblatt 1985 - any behaviour performed in relation to ones offspring
Nelson 1995 - any behaviour that contributes directly to the survival of offspring

Question 11

What is parent-offspring conflict?

Answer 11

Trivers 1974

• offspring activiely solicit or manipulate parents into providing care
• in parents best interests to preserve resources for future offspring (eg. lactation -> weight loss, v fertility)
• conflict increases with increases offspring age

Question 12

Give an example of parent- offspring conflict and impact on welfare

Answer 12

Sows in farrowing crates
- confined in close proximity, difficult to limit amount of suckling stimulation they receive
- Lie on their udders for increasing amounts of time, especially after 3rd week lactation
- CF sows in pens, farrowing crate sows show ^ plasma cortisol after 4 weeks lactation.
> Parent-offspring conflict biased strongly in favour of piglets

Question 13

How may sow-piglet conflict addressed?

Answer 13

Pajor 1994 - get-away farrowing pen
> step over piglet proof barrier to escape
> sows naturally v time spent with piglets after second week
> cf confined sows -> v milk production, v weight loss, faster return to estrus
> weaned more gradually
- advantages for mother and young

Question 14

How may maternal behaviour differ?

Answer 14

Within and between breeds
O’connor, 1985
- scored on lamb handling after birth (flee v stay with lamb)
> no genotype differences (unusual)
> Older ewes had best lamb survival rate
> test score correlated with lamb survival rate