Lecture 8 Flashcards
Define social behaviors
interactions between individuals in which one or more of the individuals benefit
describe two social behaviors
Affiliation; social behaviors which bring individuals closer
e.g. courtship and parental behaviors and Aggression or Territorial behavior: social behaviors which keep animals apart
what are the costs of living in groups
Costs
Increased ease of disease transmission
Increased competition for resources
Increase conspicuousness to predators
what are the benefits of living in groups
Benefits Anti-predator detection, defense and dilution Elevated foraging efficiency Group defense of resources Increased mating opportunities
how do social behavior change during the year in voles
During breeding season, female territories do not overlap
After breeding season, female territories do overlap and meadow voles live socially
describe the mating patterns and the habitat of the three voles
Prairie Voles Grasslands in mid-western USA Monogamous Biparental Meadow Voles Grasslands in eastern USA Highly polygamous Montane Voles Grasslands in western USA polygamous
describe how different hormones play the same role in the two sexes between voles during pair bonding
Female prairie voles develop partner preference following oxytocin infusion and Establishment of partner preference in male prairie voles is dependent on vasopressin
in zebra finches what role does the oxytocin antagonist play
Oxytocin antagonist (OTA) reduces the time spent with same sex cage mates
partner preference is facilitated and blocked by what
Dopamine agonist in NAc -> facilitated partner preference
Dopamine antagonist in NAc -> blocked partner preference
how does highly affiliative species tend to differ from solitary species
Highly affiliative species tend to have a different pattern of OXT and AVP V1a receptors than solitary species
what happens when you seperate pup voles from their families and what does this suggest
Prairie voles emit ultrasonic distress vocalization and increased levels of corticosterone while montane voles do not. this suggest that corticosterone and/or stress response may be an important mediator of partner preference
describe the different Corticosterone effects on partner preference in prairie voles according to sex
corticosterone and stress increased partner preference in male voles and did the opposite to females. adrenalectomy increases partner preference in females and did the opposite in males.
describe the similar Corticosterone effects on partner preference in prairie voles according to sex
gonadal steroid hormones showed no change in both sexes in partner preference
how does Testosterone affect Affiliative Behaviors
Males of polygamous species have higher testosterone levels
explain how testoterone has limitations in affiliative behaviors
Testosterone has no effect on polygamous or monogamous behavior on different voles
what are the Two Models of Agonistic Behavior
- Aggression and submission may represent opposite ends of a single behavior continuum
- Aggression and submission may represent different aspects of an individuals behavior
describe 4 pieces of evidence that show that androgens mediate aggressive behavior
- Seasonal variation in circulating testosterone coincides with seasonal variations in aggression
- Aggressive behaviors increase at puberty
- Males are generally more aggressive than females
- Castration typically reduces male aggression, testosterone replacement restores aggression
In many species, non-breeding season behavior is regulated by what and how?
estrogen. it inhibits aggression in long days and enhance aggression in short days.
if testosterone is removed by castration how does this affect aggression
it will block summer aggression
what blocks winter aggression
Anti-androgen or aromatase inhibitor
in Harris’s Sparrows how is social rank indicated and what does this correlate with
it is indicated by plumage color and it positively correlates with testosterone levels
describe how puberty affects aggression
During puberty the testis grow larger and the Leydig cells secrete increasing amounts of androgens into the circulation.
The resultant increase in circulating levels of androgens is associated with increased display of aggression
describe the behavior between male syrian hamsters pre, mid and post puberty.
Pre-pubescent males attack the face and cheeks of their opponent.
mid-puberty, males undergo a transition where attacks are aimed at the flanks
post puberty males attacks to the belly and rump.
what happens to the attach frequency and the contact time between hamsters as the pass through puberty
they both decline
describe the Adaptive Advantage of Pubertal Aggression
rodents such as hamsters and voles, disperse during puberty and are exposed new threats
(predators and other male’s territories) dispersing males have evolved to be aggressive which may increase their chances of survival and reproductive success
how is puberty different in primates than it is in hamsters
pubertal increase in testosterone is not always associated with increased displays of aggression.
in primates males who are victim to increased aggression and have to disperse, what are two strategies
Burst into a new troop and attempt to seize membership status (Usually met by strong resistance/aggression from resident males) or they live along the periphery of a new troop and slowly “sneak” in (Risks of starvation and predators)
name 3 characteristics that Male offsprings of high ranking females have
- Low levels of cortisol
- Risk taking personalities
- More likely to attempt to claim membership status in a new troop
name 3 Hypotheses for sex differences in aggression
- Higher androgens
- Brain are exposed to androgens during development and thus are “hardwired” (organized) differently
- Learn different culturally accepted gender roles
describe how Androgens organize AND activate aggression in mice
Male mice castrated before P6, T in adulthood ->low aggression
Female mice ovariectomized before P6, T in adulthood -> low aggression
Male or female prenatally gonadectomized, T prior to P6, T in adulthood -> typical male aggression
What are the three groups of nonapeptides and what are the corresponding species
Bony fish -> isotocin (IT) arginine vasotocin (VT)
Lungfish, amphibians, reptiles, bird -> mesotocin (MT) arginine vasotocin (VS)
Eutherian mammals -> oxytocin (OT) arginine vasopressin (VP)
Brain overlapping regions and OXT/ AVP?
Overlap between regions with high OXT and AVP receptors in prairie voles and reward system in the NAc, PFC, VP
Difference in brain circuitry of Prairie and Montane vole.
Prairie Vole; Highest oxytocin receptor density found in prelimbic cortex, BNST, nucleus accumbens, lateral amygdala
Montane Vole; Very different pattern of binding
Dopamine effect in the Nucleus Accumbens
Dopamine agonist in NAc facilitated partner preference.
Dopamine antagonist in NAc blocked partner preference
Describe the mating and reward system
Dopamine released into NAc in response to mating. The coordination of OXT, AVP, DA facilitates pair bond.
