Behavioral Endocrinology Exam 2

Sexual conflict drives

Sexual behavior

Ultimately, why would two male sea lions be likely to fight and kill each other?

If a male is able to fight and successfully kill another male, then they have a higher chance to find and successfully reproduce with a female

Sexual conflict drives

Sexual behavior

Ultimately, why would two male sea lions be likely to fight and kill each other?

If a male is able to fight and successfully kill another male, then they have a higher chance to find and successfully reproduce with a female

Usually female sea lions are the ones who pick the territories and not the males, why?

Females are the ones who take care of babies and provide reproductive opportunities, so they choose areas near the water and the males will naturally flock towards them

Explain how the fencing hermaphroditic flatworms will exhibit sexual conflict

Both of the worms will fight to try and inseminate each other, whoever gets pregnant will pick where to live and where to expend energy

How are care for offspring and reproductive output related?

When an animal cares more for their offspring, their reproductive output decreases. An example is humans

Sea turtles on the other hand lay many eggs at once and do not provide care for them

Where are the seminiferous tubules and what do they produce?

They are in the testes and produce sperm

What does the epidiymis do?

Stores sperm

What does the vas deferens do?

Sperm transportation

What does the seminal vesicle do?

Produce semen (the nourishing fluid to support the sperm during ejaculation)

When the hypothalamus sends GnRH to the anterior pituitary what is released?

LH and FSH

What does LH do?

Stimulates the Leydig cells outside the seminiferous tubes to produce testosterone

What does testosterone do after release from the leydig cells?

It is used by the sertolli cells inside the seminiferous tubule to produce DHT

it also inhibits the release of LH and FSH

What stimulates the sertolli cells to be able to use testosterone to make DHT?

FSH

What is a direct effect?

When increasing levels of a hormone cause increasing levels of behavior or some other action

What is a permissive effect?

When a specific minimum amount of hormone is needed to produce any amount of behavior or some other action

What is the physiological cause of a high sex drive

Extreme lowering of the threshold for sex

Why are androgens not the only factor in a high sex drive?

The more advanced a species is the more the experiences they have play a role in their sex drive

if someone has a lot of sex, they want/like sex, the existing androgens in their body will thus play a role in their desire to have more sex

What are the two parts of sexual behavior?

Consummatory and appetitive

What can be measured in order to understand the consummatory phase?

Copulatory lock, thrusting, number of intromission, number of ejaculation

How would motivation be described in the appetitive phase?

how much a male is willing to put up with to get to a female

measured with physical barriers

How is the removal of androgens related to changes seen in human and non human primates?

Non-Human: large individual variation where many can ejaculate for months and year after castration Human: 50% loose sex behavior in a few days, 25% over some years, and 10% did not lose sex behavior at all

What hormones play a role in penile reflex, sex performance, and motivation

T and DHT in penile reflex, T and E in sex performance, and T in motivation

Where do DHT, E, and Dopamine act

DHT in the brain, E in the mPOA, and Dopamine in the brain

Explain DHT and its role in penile sensitivity

neurons release NO which binds to outside of smooth muscle cell. Inside the cell Guanylyl cyclase activates and converts GTP to cGMP concentration. This causes Calcium to enter the ER and relax smooth muscles and cause erection

How does viagra work

it inhibits PDE 5 which converts cGMP to GMP. With PDE 5 inhibited the normal pathway for erection can occur

How is estrogen involved in performance

E is in mPOA which will electrically stimulate neurons and increase the male behavior. Male have a lot of dendritic spines for this reason. Overall E just enhances neurotransmission.

What will aromatase blockers do to male behavior

decrease it

What aspect of male sexual behavior is dopamine mainly involved in

motivation

explain dopamines role in motivation of male sexual behavior

it is a reward hormone and increases in the brain when a male is exposed to an estrus female. It is sustained during mating and drops after ejaculation. Steroids enhance dopamine transmission

what will a dopamine blocker do

stop erections

lesion to the mPOA does what to men

reduces their copulatory urges but still allows noncopulatory erections and ability to self pleasure

lesion to the amygdala does what

reduces self pleasure but allows copulatory urges

What is an associative reproductive pattern

spermatogenesis may occur at the same time mating is occurring (common for k selected species who dont have many children but provide care to their children)

How do the red sided garter snakes show environmentally controlled sex behavior

they hibernate in the winter. Males emerge first and then females and the breeding season will then last 3-4 weeks.

Mating will only start with a cold spell, hibernation, and then emergence

females will mate with one male and cue others to stop

What is a disassociated reproductive pattern

when an animal will inseminate during the breeding season with sperm that was made after the previous breeding season.

Describe the snake shemales

they have high aromatase and will convert T to E. E will mimic the female pheromone and encourage the males to come court. The males will all try to court for one another and the real females will become available to other males.

What does FSH do in the female cycle

trigger granulosa cell to release estrogen

what does LH do in the female cycle

trigger thecal cells to release testosterone

What hormone dominates the first part of the female cycle

Estrogen

E is for ___ behavior and P is for ___ behavior

sexual, maternal

r vs k selected species

r will invest in number of offspring and k will invest in the care of one

spontaneuos ovulation vs induced ovulation

S- eggs released even when there is no copulation I-Egg release is induced by copulation

Spontaneous vs induced pseudopregnancy

S- pseudopregnancy after each egg released I- no pseudopregnancy if you dont mate

when is induced and spontaneous ovulation seen

I- during group courtship and high competition environment S- when there is more male availability

why do men not have periods

androgen exposure in early life activates their development as a male later on. This inhibits ovulation

T surge

will occur about 6 hours after birth and is due to reduced t clearance in the liver and a release from mothers negative feedback. This stops ovulation in men.

not in primates

GnRH secretion is

sexually dimorphic

Pulsatile in females

pulsatile and sustained in males

Pulsatile GnRH in females

keeps receptors primed with a set level of hormones

all GnRH neurons fire at once and then stop

females pulse more when in estress so LH is more and E is controlling

Pulsatile in men

men pulse the same amount each time so steady T levels co

components of female sex behavior

attractivity

E increases in estress

females become more attractive

P increases nesting, which signals psuedopregnancy and will signal no need to breed which is less attractive to maleswh

what are the signals males get from females to judge attractiveness

pheromones

Flehman responses

curling back upper lip to smell pheromones think of horses

vomeronasal organ

important to flehman response

documented in human embryo but not fully studied in terms of function in adults

Coolidge effec

previously attractive female becomes unattractive after copulations

most common in polygamous societies

Female sex drive is usually ____ and/or ___ to men

equal greater

ultimately because they have to invest much more and have less chances to breed. So they are choosy but active in initiating copulation when they are ready

Proceptivity

during estress and driven by estrogen

the extent to which a female will initiate copulation (solicitations)

paced mating

female has control over timing and frequency of mating

Benefit of paced mating

higher mating success

males need fewer intromission for successful pregnancy

what is receptivity in females

behavior needed to successfully complete copulation

measured by mating postures and male attempts/success ratio

male female coadaptation in ring doves

male coos, female will coo independent or dependednt to the male coo. Female coo is required though for female to secrete E and follicles to develop. female receptor behavior will increase

male coo stimulates female coo stimulates LH

Estrogen and its proceptive response

it will engance proceptive behavior despite the lack of male response