http://www.canada.com/technology/Ottawa ... story.html
I have taken the liberty of hosting the original paper. The link is here: http://www.filedropper.com/1477-7827-8-36OTTAWA — For decades it’s been impossible to make most frogs breed in captivity, no matter how urgent the need for the most endangered types.
But now a University of Ottawa biologist has found a simple hormone trick that works on every frog species he’s tried it on, from here to Argentina.
It’s a brain hormone, not a sex hormone — which doesn’t stop his colleagues from talking about “Vance’s Love Potion.”
Professor Vance Trudeau doesn’t mind the name.
The potion is opening up new ways to study frogs, and to help them survive the worldwide losses of amphibians (frogs, toads, salamanders) of nearly all types.
“Can we start thinking about captive breeding on a large scale?” the biologist wonders.
The trouble has been that putting frogs in a tank somehow stops their normal cycle of releasing and fertilizing eggs.
“You may get a few croaks here and there and a little bit of play but they won’t lay eggs.”
He got the hormone idea partly from his own work years ago in fish, where a similar method is well known.
“I just thought about it for nine or 10 years and finally got around to doing it (in frogs).
“It’s like when you go for in vitro fertilization, and the woman is super-ovulated (with drugs that make her release extra eggs cells), and then you collect the eggs.”
The method keeps working. Recently, he injected leopard frogs (a common Ontario species) in late February when all frogs in the wild are frozen in mud at the bottom of a pond. The eggs came about five days later, followed by tadpoles and now “metamorphs” — juvenile frogs that still have tadpole tails.
This is only the second time on record that someone has bred the little green leopards indoors. And Trudeau did it both times.
“That leads into what Environment Canada has been trying to do in Moncton, which is to develop a captive breeding colony. They can do all the growing there, but they didn’t know how to breed them. So that’s where I come in.
“We’ve now applied this method to quite a few different species.”
He’s done batches of green frogs (another common species) and Oregon spotted frogs, so rare that they survive in just three British Columbia ponds, plus a few sites in the northwest United States.
Frogs in Argentina and Australia are hopping around because he helped scientists breed them there.
These are not sex hormones, he said. Those would shut down breeding just like birth control pills.
Instead, these are hormones from the brain and the pituitary gland which cause the animal to release sperm or eggs.
“You’re asking the animal to release its own (reproductive) hormones . . . You inject both (sexes) at the same time and just throw them together,” he said.
It will take further study in wild conditions to make sure that the offspring are healthy and act like normal frogs, but the early indications are good.
But Trudeau is optimistic that captive breeding will work, and help boost many frog populations.
“I think we can do it. If they were a food item, we’d be growing them like crazy.”
At the Vancouver Aquarium, where the Oregon spotted frogs are raised, Dennis Thoney say the Trudeau “hormone cocktail” isn’t the only tool for breeding but it’s a useful one.
It makes all the frogs breed at once, instead of spreading the egg-laying over weeks. He hopes to use the technique on another endangered frog species this year.
Ottawa Citizen
Said link is protected under the fair use provisions of copyright law as far as I am aware.
Ok. The implications of this are huge. Most amphibians will not breed under secure captive conditions. Bullfrogs you can generally get to breed in outdoor enclosures, but they are not of conservation concern. Where this is useful, is in the raising of common lab amphibians like leopard frogs, and species of conservation concern.
Most frogs require very specific conditions under which they will breed. Humidity, atmospheric pressure, days since rainfall etc. For most species, these conditions are not at all well known, and part of my dissertation is actually an attempt to develop a predictive quantitative model for the species in my regional species pool. Of the species which are endangered worldwide, this is the case for most of them, foiling any attempts at captive breeding. There has been some success with tropical explosive breeders, because all you need to do is get them in a well planted shower, but for most of the hyper-specialist tropical species, or any temperate species, there has been very little breeding success... unless you were willing to cut out the testicles of the males (they are in the body cavity, this requires killing an animal), induce ovulation through brute hormonal force in the females, physically squeeze our her eggs to artificially fertilize said eggs, and then still have low success rates.
This will permit us to successfully breed critically endangered salamander species (like Hellbenders and Iranian Newts, if the formulation can be tweaked to be appropriate), and... pretty much all of the tropical species which are being ravaged by Chytrid Fungus, allowing both re-population, and facilitating the research that will be necessary to treat the disease and wipe it out under field conditions.
This is about as optimistic as you will ever see me.
