Name: Some male fish use their tails to fan rivals’ sperm away from eggs
Brand: newscientist.com
SKU: newscientist-com-67
Availability: OnlineOnly

critic

Some male fish use their tails to fan rivals’ sperm away from eggs

preview

×To boost their chances of fertilising a nest-load of eggs, some male fish use their tailfin to fan away the sperm deposited by rivals.Scientists have previously determined that . However, the new study is the first to discover that even among animals that fertilise eggs outside the body, males have strategies to remove rivals’ sperm and increase their paternity chances.Takeshi Takegaki of Nagasaki University in Japan and his colleagues studied the behaviour of 12 nest-holding male dusky frillgoby fish (Bathygobius fuscus), common in the Indo-Pacific Ocean, when faced with rival sperm in their nests. Like most bony fish, dusky frillgobies reproduce by spawning, meaning males ejaculate semen into the water to fertilise eggs.AdvertisementNest-holding males are fish that occupy a hole between rocks and then encourage females to lay eggs inside, which the male then fertilises and protects from other males.So-called sneaker males – which are smaller but with larger testicles – literally sneak into nests to ejaculate over just-laid eggs and then swim away. Nest-holding males “aggressively chase” sneaker males away from their rock holes, says Takegaki, and then fan their tails at the nest entrance after the intruder leaves as if they’re “sweeping out” the rival semen.Takegaki’s team injected equivalent amounts of either sea water or sneaker male semen into nest-holding males’ rock holes in laboratory aquariums. They found that the nest-holding males swished their tails about 30 times more when they detected the presence of manually injected sneaker sperm compared with sea water. The fish probably pick up chemical signals from the rival sperm which influence their behaviour, he says.This active tail swishing led, on average, to an 87 per cent drop in sperm concentration in the nest, he says. While that effectively contributes to the removal of rival sperm from the nest, tail swishing has a major drawback: it also removes the nest-holding male’s sperm. To compensate, the fish then produce more of their own sperm in the nest.“Nest-holding males have to ejaculate again and again after removal of the rival’s sperm,” says Takegaki. Although fanning doesn’t remove all the rival sperm, it helps: sneaker sperm only fertilised 30 per cent of the test eggs, even though sneakers produce far more sperm than nest-holding males thanks to their larger testicles.Journal reference: Proceedings of the Royal Society B,More on these topics:AdvertisementTrendingLatestVideoFree

×To boost their chances of fertilising a nest-load of eggs, some male fish use their tailfin to fan away the sperm deposited by rivals.Scientists have previously determined that . However, the new study is the first to discover that even among animals that fertilise eggs outside the body, males have strategies to remove rivals’ sperm and increase their paternity chances.Takeshi Takegaki of Nagasaki University in Japan and his colleagues studied the behaviour of 12 nest-holding male dusky frillgoby fish (Bathygobius fuscus), common in the Indo-Pacific Ocean, when faced with rival sperm in...

public

Christa Lesté-Lasserre

The best place to find out what’s new in science – and why it matters.

newscientist.com

Credible

Speculation

Anecdotal Evidence

Generalization

Stacking the Deck

Appeal to Authority

Straw Man

Slippery Slope

Emotional Appeal

Red Herring

False Dilemma

Illogical

Moral Equivalency

Ad Hominem

Correlation w/o Causation

Semantics

Begging the Question

Faulty Analogy

Non Sequitur

Bandwagon

Dogmatism

Failing Occam's Razor

Biased

Pure Opinion

Hit Piece

Racial Bias

National Bias

Religious Bias

Financial Incentive

Political Agenda

Gender Bias

Misused Image/Video

Study Misinterpreted

Mistake

Misused Term

Science Misrepresented

Factual Error

Satire

Surface Level

Lack of Reliable Sources

Sensational

Not Credible

Investigative

Balanced

Well Sourced

Great Context

sports

entertainment

U.S.

international

business

technology

science

culture

politics

media

health

Some male fish use their tails to fan rivals’ sperm away from eggs

No article scores yet.

CRITIC REVIEWS

PUBLIC REVIEWS