• STV
  • MySTV

'Plenty of fish' effect down to single wild females, say scientists

A joint study involving the University of St Andrews discovers the secret behind guppy fish's reproductive success.

Favourite: The guppy is a popular tropical pet fish.
© Judhi Prasetyo

Scientists have discovered that an invasive species of tropical fish can colonise whole stretches of water with just one female specimen.

The guppy's prodigious ability to reproduce has led to a dramatic increase in its numbers over the last century, and it is now found in every continent except Antarctica.

Biologists at the University of St Andrews and the University of the West Indies believe the secret lies in the females' ability to store sperm for months.

They conducted an experiment in which single wild female guppies were placed in outdoor tanks. After two years, almost all the tanks contained guppy populations.

The researchers said tropical fish owners should be aware of the findings, as releasing the fish into waters where there is no guppy population could upset the ecosystem.

The popular ornamental fish, whose native home is Trinidad and the north-eastern fringe of South America, can now be found in more than 70 countries.

In places such as southern India, guppies are routinely released into water troughs, wells and small ponds for mosquito control. Heavy rains and flooding mean that the fish can find their way to streams and rivers, where they come into contact with native fish.

The lead researcher at St Andrews, Dr Amy Deacon, said: "Our findings show that the guppy's range has expanded dramatically since the early 1900s.

"Usually only one or a few fish are released. We know that the vast majority of species introduced to a new habitat in this way are unable to survive, let alone establish a population, which left us with a huge question mark.

"Sperm storage is an excellent adaptation for living in constantly changing habitats, and it might also explain the guppies' global success. Female guppies can store sperm in their reproductive tracts for many months after mating, and this enables single fish to establish populations even when no males are present.

"We also found that these populations kept all of the important behaviours that wild guppies have, so they would be well-equipped for surviving in a new environment."

The research, funded by the Natural Environment Research Council and the European Research Council, is published in the journal PLoS ONE.

One account. All of STV.

This field is required. That doesn't look like a valid e-mail format, please check. That e-mail's already in our system. Please try again.
ShowHide
Forgot password?
This field is required. This must be at least 6 characters long. Did you enter your details correctly?
If you've forgotten your details then use the 'Forgot password?' link.
Need to reset your password?

We'll send a link to reset your password to

We've sent you details on how to reset your password

Please check your email and follow the instructions.

Forgotten your email address?

Have you forgotten the email address that you previously joined with? Don't worry, by emailing enquiries@stv.tv we can help.

One account. All of STV.

This field is required. Please enter at least 2 characters
This field is required. Please enter at least 2 characters
This must be at least 6 characters long.
ShowHide
This field is required. This must be at least 6 characters long.
You must be over 16 to join STV.
This field is required. This doesn't appear to be a valid date
We need this to check that you live in an STV region.
This field is required. This doesn't appear to be a valid postcode
Would you like us to email you about our great shows and services from time to time?
We'll only send emails we think you'll like (see example) based on information you have supplied and shows you have watched on STV Player. For details on emails and advertising, see our STV & You page.
Would you like to receive emails from the Scottish Children's Lottery about draws, instant games and competitions?
We support the Scottish Children's Lottery (SCL), which is managed by our colleagues at STV ELM Ltd. You can find out more about the SCL on its website, including its Privacy Policy.

By continuing you agree to our Terms of Use, and understand our Privacy and Cookie Policies.

Upload Profile Picture

Please make sure your image is under 2mb in size and a valid JPG, PNG or GIF.

Are you sure?

Unfortunately, you'll be unable to access our premium content. We’ll be sorry to see you go, but if you change your mind you can rejoin us at any time.

Please verify your STV account

Please verify your STV account using the email we sent you. If you have lost the email, we can send you another one, just click the button below.

Thanks

We've sent you a new verification email.
Please check your email and follow the instructions to verify your account.

Welcome to STV
Thanks for joining us.

Oops!

Sorry, you must be at least 12 years old to place a vote for your Real Hero.

Please review our Voting Terms of Use for more information.

Oops!

Sorry! It seems that you are using a browser that is incompatible with our voting service.

To register your vote please copy the below URL in to your regular mobile browser. We recommend Google Chrome, or Safari.

http://shows.stv.tv/real-heroes/voting

Oops!

Sorry, you seem to have already voted in this category.

Thanks for voting

Now share your vote with friends on your social network

Share on twitter Share on facebook

Cast your vote

Please register or sign in to continue.

Cast your vote

This field is required. This doesn't appear to be a valid date

Cast your vote

Please fill out this form to cast your vote. As you are under 16 years old you will not create an STV account. Why do we need these details?

This field is required. Please enter at least 2 characters
This field is required. Please enter at least 2 characters
This field is required. That doesn't look like a valid e-mail format, please check.
Location This field is required.
Parental Consent This field is required.

That's you. All that's left is to click the 'Submit Vote' button below. By doing so, you confirm that you and your parent or guardian have read and accept our Voting Terms of Use, Privacy Policy and Cookie policy, and that the details you have entered are correct. We'll look after them as carefully as if they were our own.