1
Q
parental investment theory
A
amount of assistance a parent provides reflects an optimal evolutionary strategy for maximizing fitness
- extent to which parents compromise their ability to produce more offspring in order to assist current offspring
- can lead to conflict b/w the parent and child
- consider gamete size/number of offspring produced
2
Q
parental behavior
A
behaviors performed in relation to the offspring that contribute to the survival of fertilized eggs/ova
3
Q
altricial young
A
immature, helpless young
- female may or may not display maternal care (may depend on the number of offspring produced)
ex: fish, rats, mice
4
Q
precocial young
A
young are born well-developed, may be able to survive without parental care
- ex: hoofed animals, whales, guinea pigs
- more investment during development, less parental investment needed postpartum
5
Q
semi-precocial young
A
need a substantial amount of care, but can thermoregulate and cling to the mother
ex: humans, puppies
6
Q
mammalian parental behaviors
A
nest building, food, shelter, protection, play with older siblings, pup retrieval, warmth, cleanliness, aggression
7
Q
bird parental behaviors
A
nest building, incubation, brooding, care until independence
8
Q
birds: 4 patterns of parental care
A
- nest parasite (ex: cowbirds, cuckoos)
- solely maternal care (ex: chickens)
- solely paternal care (ex: mallee fowl, jacana)
- biparental care (most common)
9
Q
Evolutionary perspective on biparental care in birds
A
most young birds are helpless and require constant food and warmth to survive, if the male did not assist the female with parenting, the young would most likely die and the males own reproductive fitness would decrease
10
Q
brood pouch
A
- formation induced by increased prolactin concentrations
- place on chest that loses its feathers and becomes increasingly vascularized to allow for a more efficient heat transfer from the parent to the chick
11
Q
crop milk
A
- formation induced by increasing prolactin concentrations
- produced in the crop sac (an endocrine gland); resembles small curd cottage cheese; contents of crop sac change as the bird matures and gets older (milk–> predominately insects and seeds; changing contents dependent on decreasing prolactin levels)
12
Q
endocrine correlates of bird behavior: sex steroids
A
sex steroid hormones increase with the onset of courtship behavior (estrogens), peak at egg laying= oviposition; and decrease to baseline prior to incubation (this is when we see a peak in prolactin levels)
-progesterone also induces incubation and inhibits courtship behaviors
13
Q
endocrine correlates of bird behavior: prolactin
A
prolactin concentrations increase at egg laying, peak at incubation, and gradually decrease post-hatching DEPENDENT ON DEVELOPMENTAL STATE OF CHICK
- altricial young: prolactin levels remain elevated (crop milk, brooding, brood pouch)
- precocial young: supervision generally needed, but not extensive parental care
14
Q
broodiness and prolactin
A
incubation of the eggs for warm, protecting, covering, and warming the young under the wing
**elevated levels of prolactin in every female bird species during incubation
15
Q
Daniel Lehrman: ring necked doves
A
conducted research on ring necked doves that studied the hormonal influences on courtship and parental behaviors
- extended the idea that hormones affect behaviors; hormones can affect behaviors, and behaviors can feed back to affect hormone secretion
- bi-directional relationship between hormones and behavior
16
Q
categorizations of mammals
A
- marsupials
- monotremes
a. no pouch
b. pouch - eutherian
a. altricial
b. precocial
c. semi-precocial
17
Q
marsupials
A
produce highly altricial young that resemble embryos more than offspring
- pouch: contains mammary glands and serves as a receptacle for the young
- pouch adaptation: allows the mom to remain mobile, forage for food, and escape from predators all the while carrying her infant
- short gestation: more favorable in harsh climates
- ex: wallaby, kangaroo, koala, opossum
18
Q
monotremes
A
produce very altricial young that are born as EGGS but nursed with milk when born
- pattern 1: no pouch, animal will build a nest, incubate the eggs, nurse at birth: ex-platypus
- pattern 2: pouch, animal will carry the egg in their pouch where the infant will live when it hatches and nurses- ex: spiny anteater= echidna
19
Q
eutherian
A
produce placentas in pregnancy
- altricial: produce young with a significant amount of care, food, shelter, mom must clean off amniotic fluid from young when born to stimulation excretion of waste; young often unable to thermoregulate; pup retrieval
- precocial: high degree of independence when born
a. hider type: young hidden at nest for 7-10 days while the mom forages for food and occasionally visits to nurse
b. follower type: follow the mom around from birth - semi-precocial: helpless offspring BUT can thermoregulate and cling to the mother
-tend to all live in more stable environments and climates; young more developed and gestation tends to be longer
20
Q
placentophagia
A
consumption of the placenta post-birth
21
Q
when do we see paternal behavior in mammals
A
- when it increases the male’s reproductive fitness
- the female cannot rear the young alone successfully without male support
- certainty of paternity is high: male unlikely to help female rear offspring if he is not certain it’s his child–he would not be increasing his own reproductive fitness if he was investing his time into an offspring that was not his own
22
Q
california mouse
A
- example of a mammalian species that displays high degree of paternal behavior
- male exhibits the same behaviors as the female (minus lactation) and spends just as much time with them
- equal time spent in nest, building the nest, carrying young, clean and lick anogenital area, assist with the birthing process
- monogamous; long-term pair bonds
23
Q
marmoset
A
- example of a mammalian species that displays high degree of paternal behavior
- males assist during birth, chew food for the babies, carry the young
- also monogamous
24
Q
testing mammalian parental behavior: rat pup presentation
A
- how long does it take for a rat to respond parentally to a rap pup (latency and types of behaviors expressed)
- varies depending on endocrine state and past pregnancies
25
nulliparous and male response to rat pups
- never have been pregnant
- will either ignore pups or respond aggressively
- both males and nulliparous females will respond parentally to rat pups 5-6 days after continuous exposure to rat pups--> NOT hormonally mediated
26
primiparious and their response to rat pups
first pregnancy; pregnant females will respond maternally to pups if presented with them during the last few days of her pregnancy
-the immediate response to rat pups in pregnant females is HORMONALLY MEDIATED
27
multiparious and their response to rat pups
having multiple pregnancies
| -primed with enhanced sensitivity to rat pups; display a lower latency to behave maternally
28
concaveation
process of becoming sensitizing to newborns so that full behavior is expressed
- independent of hormones, rather stimulated by the mere presence of the pups (may be acting on dopamine and reward pathway)
- continuous exposure to rat pups may decrease the initial fear as she becomes accustomed to rats
29
test of maternal motivation: place preference test
maternal motivation tested by seeing if the mom prefers a chamber associated with her pups or a chamber associated with cocaine
- day 8: prefer pups
- day 16: prefer cocaine
- day 10: equal number prefer pups and cocaine: represents a midpoint shift in either...
a. reward properties of pups
b. motivation of rat dams
30
MPOA and maternal motivation
MPOA is a part of a circuit that mediates both the motivation and performance of maternal behaviors
-circuit of the chemosensory pathway: VNO, olfactory bulbs, MPOA, stria terminalis, amygdala
31
Nucleus accumbens and maternal memory: Alison Fleming
maternal memory: depends on experience with the pups and PROTEIN SYNTHESIS; formed postpartum and decreases future latency of the expression of maternal behavior
-Alison Fleming: injected a protein synthesis inhibitor into the shell and core of nucleus accumbens (also associated with dopamine)--> prevented the consolidation of memories--> blocked expression of future maternal behaviors
- only injections of protein synthesis inhibition into the shell of the NA disrupted maternal behaviors, no effect in core
- maternal behavior was not disrupted by protein synthesis behavior if the mom had over 24 hrs. of contact with the pups
32
Nucleus accumbens and dopamine: Alison fleming
- nucleus accumbens receives dopaminergic projections that are associated with the reward pathway
- injections of dopamine agonists into the shell--> expression of maternal behaviors
- injections of dopamine antagonists--> inhibition of maternal behaviors and BLOCKING OF MATERNAL MEMORY
- dams with previous maternal experience had higher concentrations of dopamine than dams without prior maternal experience (DA levels of multiparous F's> DA levels of primiparous F's)
33
MPOA and the chemosensory pathway: Alison Fleming
- VNO projects to the olfactory bulbs--> projects to the amygdala--> project to the MPOA via the stria terminals
- lesion anywhere along this pathway will DECREASE the latency of maternal behaviors
- why? pups smell terrible-> may be why nulliparous F's and males are afraid of rat pups
- disruption/lesioning of individual parts within this chemosensory pathway--> decrease ability to process these negative smells (negative valence decreases, positive valence increases--> pup become more attractive)
34
MPOA, chemosensory pathway, hormones associated with end of pregnancy
- hormones associated with the end of pregnancy change how the smell is processed (maybe the smell is less repulsive? maybe it's valence decreased? more pleasing)--> more interactions with pups
- conclusion: olfactory bulbs and VNO inputs to the MPOA inhibit maternal behavior in rats--maternal behavior will occur when the MPOA is released of this inhibition by hormones associated with the end of pregnancy
35
Judith Stern: Role of Tactile feedback
- conducted research over the importance of tactile feedback for maintaining maternal behavior in rats
- can rid of maternal behaviors (like nest building, licking, retrieval) by desensitizing nerves around the mouth
- also found that tactile stimuli from the pups was important for proper nursing behavior
36
Nongenomic transmission of parenting styles: glucocorticoid receptors, methylation, histones
- good maternal behavior (licking, grooming, proper nursing position)--> increased glucocorticoid receptor expression in pups--> resistant to stressors as adults--> likely to be good mothers and express these same maternal behaviors as adults
- ^maternal behaviors that have been primed--> demethylation and removal of histones--> increased gene expression and produced of glucocorticoid receptors--> priming for future maternal behaviors
37
Jay Rosenblatt: endocrine correlates of maternal behavior
set up a parabiotic transfusion wherein blood from a female who had just given birth was transferred to a nulliparous female--> induction of maternal behaviors immediately
-pointed to the idea of some blood borne factor that was responsible for the induction of maternal behaviors
38
rabbits: nesting--estrogen, progesterone, prolactin
near birth, pregnant doe builds nest with her fur that is falling out as a result of the increasing estrogen: progesterone ratio (increasing E, decreasing P) and subsequent increase in prolactin as a result of this increasing E:P ratio
-if we inject dopamine (prolactin inhibitor)--block nest building behavior; suggests prolactin is needed for nest building behavior
39
estrogen, progesterone, and prolactin in relation to induction of maternal behavior
1. the brain must be primed with estrogen and progesterone for prolactin to induce maternal behavior
2. estrogen and progesterone need prolactin to decrease the latency of maternal behavior
40
estradiol and MPOA
estradiol implants into the MPOA induce maternal behavior
- the number of estradiol receptors increase during pregnancy
- protein product of estradiol receptor activation: OXYTOCIN RECEPTORS
41
oxytocin and maternal behavior: rats
oxytocin receptor binding is higher in lactating females who display higher levels of licking and grooming behavior compared to females who do not express these maternal behaviors
- pup retrieval: oxytocin acts on the left auditory cortex (more firing--> more sensitivity to pup cries)
- nulliparous F: injection of oxytocin--> pup retrieval
- inactivation of auditory complex: no pup retrieval
42
oxytocin and sheep
oxytocin important for maternal acceptance and maternally motivated behaviors
- nulliparous female+estradiol+progesterone (primed brain):--> no expression of maternal behaviors
- nulliparous female+estradiol+progesterone+vaginal stimulation--> release of oxytocin (birth simulation)--> full expression of maternal behaviors, accept foster lamb
43
hormonal correlates of paternal behavior: california mouse
-rat pup presentation: expression of paternal behaviors highest in fathers>expectant fathers>non-mated males
-prolactin levels:
fathers>expectant fathers>non-mated males
- testosterone needed to the expression of paternal behaviors (unlike the marmoset)
- exerts its actions through estradiol
44
hormonal correlates of paternal behavior: marmoset
- paternal males: 5x prolactin levels, lower levels of T
| - smelling infants--> act to decrease testosterone levels
45
hormonal correlates of paternal behavior: humans
fathers: higher levels of prolactin, lower levels of cortisol, higher levels of E
46
proposals for termination of maternal behavior
1. Mom: increasing levels of prolactin stimulates the production of corticosterone--> increase in metabolic rate--> increase in body temperature (may be that she is physically uncomfortable around pups b/c they radiate increasing quantities of heat as they get older)
2. pups: as they get larger, they are better able to thermoregulate and exude larger quantities of heat--> mom unable to cool off
3. pups leave the nest to forage for food and find their way back via caecotrophs (small partially digested bits of food produced by the mother)
Behavioral Endocrinology
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