In a breathtaking transition for sexual to asexual reproduction, Leonie the zebra shark has given birth without a mate.
Leonie, homed at the REEF HQ Aquarium in Townsville, Australia, had several litters with a mate before the two were separated in 2012. Having lived apart from males for the past few years, her keepers were shocked to find she had laid eggs that grew to produce three healthy baby sharks in April of 2016.
In a quizzical attempt to unfold Leonie’s transition from sexual to seemingly asexual reproduction, biologists investigated the possibility of her storing sperm to use for later reproduction. However, upon testing the pups they discovered the young sharks only contained traces of Leonie’s cells.
Asexual reproduction, known as parthenogenesis, occurs when embryos develop without fertilization by a male’s sperm. This case is the first seen within zebra sharks and is more common in plants and invertebrates, however scientists have been documenting an increase in ‘virgin births’ throughout typically sexually reproducing species. These include: komodo dragons, wild pit vipers, blacktip sharks, chickens and turkeys.
This, however does not detract from the extraordinary nature of Leonie being one of the rare cases to be known to have given birth by sexual reproduction to then make the switch to asexual reproduction after being without a mate for several years.
Scientists working on Leonie’s case seem to believe that she adapted to her circumstances and made the switch as a result of losing her mate, but are still questioning how such a thing might happen in the wild. The zebra shark is listed as endangered on the International Union for Conservation of Nature’s Red List of Threatened Species and thus information on how the species could reproduce in the wild despite lack of suitable mate could be crucial to their survival.
With an increase in asexual reproduction it is common to see a loss of genetic diversity as the generations span and scientists claim they will be monitoring Leonie’s babies to asses whether they can indeed have their own pups with a male partner.
So as it appears, this Valentine’s Day, Leonie has given up on love because she simply has no need for it and will carry on providing life without the need for a box of chocolates or bouquet of roses.