Lecture 9: Fish reproduction Flashcards
What are the two main stages of sexual selection in fish?
Before mating: Mate choice and male-male competition.
After mating: Sperm competition and cryptic female choice (CFC).
What is mate choice, and what traits influence it in fish?
Mate choice is the selection of a mate based on traits that signal quality, such as bright coloration, body size, and ornamentation.
Why do female sticklebacks prefer redder males?
Red coloration signals parasite resistance and overall health, leading to better offspring survival
What is sperm competition, and when does it occur?
Sperm competition occurs when sperm from multiple males compete to fertilize a female’s eggs, common in species with multiple mating events.
How do males adapt to sperm competition?
Males adapt by producing:
Larger testes (more sperm).
Longer, faster-swimming sperm.
More viable sperm.
What is cryptic female choice (CFC) in fish?
CFC is the ability of females to selectively use sperm from preferred males after mating, often to avoid inbreeding.
How do female guppies demonstrate cryptic female choice?
Female guppies use less sperm from closely related males, reducing the risk of inbreeding
What are the two main types of male-male competition?
Direct competition: Fighting for mates or territories.
Indirect competition: Sperm competition and sneaky mating tactics.
How do male sarcastic fringehead fish compete for mates?
Males use mouth-gaping displays to assert dominance and gain access to females.
What are sneaker males, and how do they reproduce?
Sneaker males avoid direct competition by fertilizing eggs covertly, common in species with high male competition (e.g., plainfin midshipman).
What are the consequences of anthropogenic pollutants on fish reproduction?
Pollutants like ethinylestradiol (EE2) reduce male courtship behavior and affect sperm quality, disrupting reproduction.
What is multiple paternity, and why is it common in sharks and rays?
Multiple paternity occurs when a female’s offspring have different fathers. It is common in sharks due to sperm storage in the oviductal gland.
How does sperm size relate to sperm competition?
In species with high sperm competition, males produce longer sperm that swim faster to increase fertilization success.
What extraordinary behaviors are seen in plainfin midshipman males?
Plainfin midshipman males exhibit two strategies:
Parental males: Defend nests and attract females with sound.
Sneaker males: Avoid competition and sneak fertilizations.
