Flashcards in Fish endocrinology - sexual dimorphism Deck (18)
What are the different kinds of sexual dimorphisms?
What are the main cues to tell males and females apart?
How do visual differences contribute to mate choice in swordfish?
Length of tail and contrast of the tail influences how many females choose the male.
What are tubercles? How do they contribute to mate choice?
Bumps on the male head that can be tactile or visual.
Females can choose based on how large they are.
What are the limitations to visual signals?
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
Usually, it is the ______ that does the calling and the _______ that responds.
What are the limitations to acoustic signaling?
1 - Predation
2 - Energetically demanding
3 - Limitation to how far the sound propagates
What are some benefits to acoustic signaling?
Propagate in all directions, regardless of current.
Females can follow the sound.
What are the major pheromones in fish?
20BP or 20BP-S
What does the ratio of sulfated to non-sulfated do?
Can identify species and reproductive state
Pheromones work really well _______ and can also be used in _______.
Often, one pheromone will be a ______ attractor and the other will be a final _______ ______.
final mating factor
What are some issues with pheromones?
Heavily influenced by current
Tend to be effective only in limited directions (due to current)
Fish are highly sensitive to ______ cues and can detect them in lower concentrations but, these are still limited by _______.
Describe parental care in blue gill.
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.
Describe parental care in cichlids.
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.
Describe parental care in seahorses.
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.