Flashcards in Parental Behaviour 7 Deck (18)
What is the parental investment theory proposed by Trivers defined as?
Any investment by the parent in an individual offspring that increases the offsprings chance of surviving at the cost of the parents ability to invest in other offspring
What are the three conflicts that can influence the amount a parent invests in its offspring?
1. Between parents on how much care each should provide
2. Between siblings on how much care each should demand
3. Between parents and offspring on supply and demand for care
What are precocial young?
Born able to be independent of the parents- born able to see and walk etc.
What are altricial young?
Reliant on parents to care and feed them
What changed are associated with incubation in chickens?
Large amount of time sitting on egg
Formation of brood patch
Stop laying and ovaries regress
Aggressive pecking when approached
Voluntary reduction of food intake and body mass
What hormone even if injected alone can sustain nesting?
What is also needed in order to stimulate prolactin leading to nesting behaviour?
Tactile stimulation of the brood patch
What releasing factor controls the release of prolactin from the pituitary in birds?
Vasoactive intestinal peptide (VIP)
What happens if immunisation against VIP or prolactin in chickens and turkeys occurs?
It inhibits incubation behaviour
What regions of the brain were found to be important for incubation and parental behaviour?
POA and basal hypothalamus
Both are also binding sites for prolactin
What is the difference in prolactin levels in precocial and altricial species?
In precocial species prolactin levels decrease after hatching, but it is extended in altricial species
What was found in the long term study on scrub jays?
The young remain in the parents territory for several years as helpers- alloparenting
Prolactin increases in the helpers but it’s lower than the parents
What are the three major maternal behaviours common to mammals?
1. Lick pups after birth
2. Adopt nursing posture
3. Bring escaped pups back to the nest
What did Moltz et al. find in his hormone replacement study?
A sequence of oestradiol-progesterone-prolactin reduced the onset of maternal behaviour from 6 days to 35hrs
But still not as rapid as after normal birth
How is prolactin released in mammals?
By the brain via dopamine rather than VIP as in birds
What do mPOA lesions do to maternal behaviour?
Reduce both appetitive and consummatory behaviours
What is the lateral POA important for in maternal behaviour?
Pup retrieval, nest building and nursing behaviour