PARENTAL BEHAVIOR
II. VARIABILITY
B. Rhesus monkey maternal behavior
1. Background
a. Social Organization
1. Rhesus monkeys live in large multi-male troops (20-180 individuals).
2. They react very aggressively to strange troops (think back to the vervet monkeys, where they actually give alarm calls to strange vervet monkey troops). This aggressive response is termed xenophobia which means "fear of strangers."
3. Females remain in their natal troop forming the core of the group.
4. Females form subunits called matrilines which are female kin groups (grandmothers, mothers, daughters etc.).
b. Habitat
1. Rhesus monkeys occupy many different habitats, forests, agricultural areas, and towns and cities.
2. Why are rhesus monkeys referred to as "weed macaques"
c. development
1. gradual and complex
2. paths for male and female infants diverge early
3. Females stay close to their mothers and sisters whereas males join all-male playgroups
d. emigration
1. Males emigrate and attempt to join another troop
2. This is very difficult because as noted above, troops react with aggressiveness to strangers. It is estimated that 30-45% of males do not survive the emigration.
2. mother-infant relationships
a. elaborate and complex,
b. series of stages which can only be understood by comparing and contrasting development from the mother's perspective and from the infant's perspective
3. The mother's perspective
a. Before we describe the stages, we will identify the four major behavior patterns that characterize how mothers respond to infants.
1._______________________________________
2. __________________________________
3. retrieve (pick up infants)
4. reject (remove infants from the ventral surface or prevent the return of the infant to the mother's ventral surface)
b. Maternal Stages (mothers go through stages, how long they spend in a stage is variable, but the order is invariant)
1. attachment (what happens in this stage?)
2. ambivalence
Cradling and restraint declines. Retrieval reaches it's peak and mild rejection and punishing responses are on the rise
3. relative separation (what happens in this stage?)
4. The infant's perspective
a. A series of behavior patterns are associated with infant behavior including
1. ventral contact (infant clings to the mother's ventrum
2.____________________________
3._____________________________
b. Infant Stages (Like mothers, infants also go through stages. How long they spend in a stage is variable, the order is invariant)
a. Organic Affection -takes place during the first 10 days of life. Infants have a set of reflexes including climbing up vertically, clasping, rooting for the nipple etc.
b. Comfort and attachment (what happens in this stage?)
c. Exploration
ventral contact is declining, infants are spending a significant amount of time exploring their environments. Forays away from the mother now last for longer periods of time
d. Relative Independence (what happens in this stage?)
5. Variability in mother-infant relationships
Although there are commonalities across mothers and infants, there is also considerable variation in how mothers and infants behave in the mother-infant relationship. Below we consider first the factors that make some mothers behave differently from other mothers and then we consider genetic/prenatal differences in the infants.
6. Maternal Contributions to Variability
a. experience with infants (two types)
1. How do primiparous (first-time) mothers behave?
more wary, more protective in that they restrain infants more and reject infants less
2. How do multiparous (experienced) mothers behave?
b. experience with one's own mother (two types)
1. early experience (How your mother treated you determines how you treat your own infants)
2. concurrent experience (Because mothers and daughters can have infants in the same year, this idea refers to whether daughters with infants "copy" their mother's behavior to her infant in that year).
3. Which type appears to explain rates of punishment mothers direct to infants?
4. Which type appears to explain styles of contact?
c. dominance status (infants take on the rank of their mother) Dominant mothers encourage independence at an early age, spend less time in contact and more frequently reject their infants.
7. Infant Contributions to variability
a. sex
1. what is the effect?
2. How is it discerned?
b. Genetic based temperaments (one is termed reactivity)
1. monkeys have different reactions to novel events
a. about 80% are characterized as __________reactors
b. about 20% are characterized as __________reactors
2. These differences can only be discerned under challenge (what does this statement mean?)
3. These different temperaments have physiological markers
a. Stress responses (how do they differ in the two temperaments?)
b. Heart rate patterns (how do they differ in the two temperaments?)
c. Genetic based temperaments (another is termed impulsivity) - What are the markers for this temperament?
III. ASPECTS OF PARENTING
A. Offspring Recognition (offspring recognition or the ability to discriminate your own from unrelated offspring occurs in some species but not in others, Why?)
1. What is the function of offspring recognition?
2. Comparisons of colonial nesting versus solitary nesting species
a. which group is likely to show offspring recognition?_____________________b. Studies of swallows
1. colonial nesters (bank and cliff swallows)2. solitary nesters (rough-winged and barn swallows)
c. Predictions
1. Distinctiveness of offspring should be more well developed in:
2. parents should be more discriminating in:
3. _____________________reject other offspring whereas
_______________________should accept other offspring
What does the following table reveal in regard to the predictions?
SPECIES
Offspring Distinctive
Parents Discriminating
Accept Other Young
Bank Swallows
yes
-
-
Cliff Swallows
yes
yes
-
Rough winged Swallows
no
-
yes
Barn Swallows
no
-
-
B. Adoption of nonrelatives
1. why adopt? (would seem to be a bad strategy in that fitness is reduced)
a. learned recognition of offspring carries costs and benefitsb. for some species, the chance of rejecting one's own offspring carries a higher risk than the occasional acceptance of a stranger's offspring (but remember to consider not only the parent's perspective but the offspring's as well; see the example below)
Adoption in Ring-billed Gulls
a. The ring billed gull nests in large colonies during the breeding season. Given their colonial nature, gulls should recognize their own offspring and adoption of unrelated offspring should be relatively rare.
b. However, Brown (1998) and others have shown that adoption can occur at rates that vary from 4-14% of the colony chicks.
c. Previously, adoption has been viewed primarily from the perspective of the parent, and in that context, it is difficult to understand how adoption might persist.
d. As we have shown with the rhesus monkey, it is important to consider the perspective of both the parent and the offspring. Brown (1998) suggests that the behavior persists because of benefits to the offspring. Thus, some chicks appear to leave the natal nest to seek other parents.
e. Ring-billed gull females lay 2-3 eggs several days apart. The eggs hatch on different days and the chicks are of different size and mass. The first chick that hatches from the egg is referred to as the a-chick, the second as the b-chick, and the third as the c-chick. Brown showed that this variable in part determined whether chicks left the natal nest.
Table 1: Survivorship in Chicks (fill in the table below)
Chick Type Survivorship Percentage a-chick
b-chick
c-chick
Table 2: Percentage of Chicks Leaving the Natal Nest (fill in the table below)
Chick Type leave nest percentage a-chick b-chick c-chick Of the chicks leaving the nest, most were accepted into nests where the adoptee was larger than the a-chick.
c. but what about situations in which the adoptee may kill off or endanger the remaining offspring
2. Brood parasitism (why accept another species eggs?)
a. Most birds may be following a simple strategy of:
b. but why don't birds recognize their offspring and eject the others (we need to consider this question from a cost/benefit perspective). There may be costs to ejecting another species' offspring
Cost 1:
Cost 2: studies of prothonotary warblers (what does the graph show?)
Cost 3: Mafia Hypothesis
Study involving magpies and cuckoos (what was the outcome when magpies removed cuckoo eggs?)