Fish endocrinology - sexual dimorphism

Question 1

What are the different kinds of sexual dimorphisms?

Answer 1

Visual differences
Acoustic differences
Chemical differences

Question 2

What are the main cues to tell males and females apart?

Answer 2

Visual cues

Question 3

How do visual differences contribute to mate choice in swordfish?

Answer 3

Length of tail and contrast of the tail influences how many females choose the male.

Question 4

What are tubercles? How do they contribute to mate choice?

Answer 4

Bumps on the male head that can be tactile or visual.

Females can choose based on how large they are.

Question 5

What are the limitations to visual signals?

Answer 5

1 - Only work in light:
- don’t work in the dark, turbid water, during the night, at depth

2 - More open to predation

3 - Only works close to the signaller

Question 6

Usually, it is the ______ that does the calling and the _______ that responds.

Answer 6

Male

female

Question 7

What are the limitations to acoustic signaling?

Answer 7

1 - Predation
2 - Energetically demanding
3 - Limitation to how far the sound propagates

Question 8

What are some benefits to acoustic signaling?

Answer 8

Propagate in all directions, regardless of current.

Females can follow the sound.

Question 9

What are the major pheromones in fish?

Answer 9

20BP or 20BP-S

Question 10

What does the ratio of sulfated to non-sulfated do?

Answer 10

Can identify species and reproductive state

Question 11

Pheromones work really well _______ and can also be used in _______.

Answer 11

close-by

distance

Question 12

Often, one pheromone will be a ______ attractor and the other will be a final _______ ______.

Answer 12

distance

final mating factor

Question 13

What are some issues with pheromones?

Answer 13

Heavily influenced by current

Tend to be effective only in limited directions (due to current)

Question 14

Fish are highly sensitive to ______ cues and can detect them in lower concentrations but, these are still limited by _______.

Answer 14

pheromone

distance

Question 15

Describe parental care in blue gill.

Answer 15

Male will form and nest and guard the babies.
Guard the babies until they have absorbed the yolk sac and until they can swim on their own.
They will attack invaders.

Question 16

Describe parental care in cichlids.

Answer 16

Will mouth brood.
Take larvae or eggs in mouth and hold them there until offspring are large enough to swim away.
Sometimes have expanded mouth cavities.
Typically, don’t feed during this time but take water from gills.

Question 17

Describe parental care in seahorses.

Answer 17

Male will have a brood pouch where it keeps the baby fish.
Can still feed and protect the babies at the same time.
When the babies come out, more or less freeswimming.

Question 18

In all cases of parental care, takes energy from ______ but increases _______ success of offspring.

Answer 18

parent (parents)

survival