Using the cane toad's poison against itself

Jun 13, 2012
Professor Rick Shine: "This is the first powerful tool we have created to control cane toads."

(Phys.org) -- An effective new weapon in the fight against the spread of cane toads has been developed by the University of Sydney, in collaboration with the University of Queensland.

"This is the first powerful tool we have created to control ," said Professor Rick Shine, from the University's School of and the lead author of the study which is published in the Proceedings of Royal Society B on Wednesday 13 June.

The new research shows that the same powerful poisons cane toads use to devastate can be used as a weapon against the toads themselves - by using the poison as 'bait' in traps set in waterbodies to catch toad tadpoles.

"A chemical 'bait' created from the toads' poison is a real magnet for toad tadpoles," Professor Shine said.

The biggest obstacle to getting rid of cane toads is that a single clutch (the amount of eggs laid at a time by one female) can contain more than 30,000 eggs.

"This means that even if you catch and kill 99 percent of the adult toads in an area, the few that are left can produce so many offspring that before you know it you are back to where you started - just as many cane toads as ever," Professor Shine said.

The only way around the problem is to stop the toads from reproducing, Professor Shine explains.

The study discovered the from the shoulder (parotoid) of dead toads can be used as bait. It is cheap, easy to obtain and highly attractive to toad tadpoles - but repels the tadpoles of native frogs.

"This is perfect to use in funnel-traps in ponds to catch toad tadpoles. Other native fauna such as fishes and insects aren't attracted to this chemical but toad tadpoles are incredibly good at detecting it, and they search for its source as soon as they encounter it," Professor Shine said.

"When we use this chemical as bait in a funnel-trap we catch thousands of toad tadpoles and almost nothing else. In one natural pond, we collected more than 40,000 toad tadpoles in less than a week. And I think we got them all - over the next few weeks, not a single toad emerged from that pond."

The researchers hope to train people from local 'toad-busting' community groups in the proper methods of collection. Until then, even a dead toad inside a funnel-trap can serve as an effective 'bait' for toad , without requiring any risky squeezing of poison glands.

The toad's poison is very dangerous to humans as well as many native species (and pet dogs, etc) so collecting it must be done very carefully, and by someone who has been trained in the right methods; and is wearing suitable protective equipment.

"In continuing work with our collaborators at the University of Queensland we are developing an even stronger, safer, and easier-to-use bait," Professor Shine said.

"To do this, we will isolate the active agent in the toads' secretion, and use it in pure form without all of the associated poisons."

Cane toads (Rhinella marina) are spreading through tropical Australia with a devastating impact on native species. Predators that try to eat are killed by the invader's powerful poisons; in some local populations of crocodiles, goannas and quolls, more than 95 percent of the animals are killed within a few months of the toads' arrival.

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User comments : 12

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Skepticus
1 / 5 (6) Jun 13, 2012
The cane toad are lucky to settled in Australia. If they were in SEA, they would certainly be eaten to near extinction. For those who don't know, toads properly prepared ( no skin, gut, head, organs whatsoever) tastes better than chicken. I have to feel sorry for the high-browned, nose-up-turned Westerners. Their woefully limited range of food is quite sad.
Scottingham
5 / 5 (5) Jun 13, 2012
Not all frogs taste the same. These might taste like crap. Way to extrapolate into a western society bash though.
Sinister1811
2.3 / 5 (9) Jun 13, 2012
The thing about Cane Toads, though, is that they are highly toxic/poisonous. Which is a big problem for any animal that feasts on them as they usually become terminally ill. The toxins they carry can be fatal. But I don't know if they could be prepared in such a way that they could be edible.
Kato77
3.5 / 5 (2) Jun 13, 2012
Skepticus, people have talked about eating the toad, but the problem as the article stated is that many people do not have training in handling the animal. In addition it isn't a question of food but uncontrolled invasive species. It's racist of you to make such broad general assumptions.
Skepticus
1.6 / 5 (5) Jun 13, 2012
There is nothing racist intended in my comment. Just the truth that Asians eat EVERYTHING under the sun and then some, and the proven reluctance of the westerners to consider something new as food apart from their traditional ones. Google "Asian Carp" and you tell me how many westerner find it tasty, and how many lambasted it as crap, while 1/4 of the world population consider it a delicacy. Who is the racist here?
Deesky
5 / 5 (4) Jun 13, 2012
Who is the racist here?

While I'm not saying you're racist, comments like "the truth that Asians eat EVERYTHING under the sun and then some" do not help.
gmurphy
3 / 5 (1) Jun 14, 2012
@Skepticus, why eat insects or toads when you can have a delicious mouth-watering burger, not the MacDonalds crap but a proper home cooked extravaganza, lathered with cheese, peppers and other tasty treats. Sure, it's not the healthiest to eat and it's not great for the environment either but it's damn tasty. Chitin and toad poison can't really compete, imho.
alfie_null
3 / 5 (1) Jun 14, 2012
Regarding eating the toads: just market it like Fugu.
Regarding tasting better than chicken: chicken is bland. It has no taste, just mouth feel.

Regarding "limited range of food" and the implied limited range of tastes (and following comments about other meat sources): for a wider variety of taste sensation, my experience has been the menus of vegetarian restaurants is superior to that found in meat-focused menus.
kaasinees
1.7 / 5 (3) Jun 14, 2012
gmurphy: your mindset is exactly why humanity is in trouble.

Lay off the meat if you want to humanity to survive.
Skepticus
3 / 5 (8) Jun 14, 2012
@Dessky: I admit a bit of hyperbole here. but, perhaps due to the warm climate and therefore a profusion of things, and a long history of hardship, thus a determination of trying everything to keep the stomach full, Asians eat (or try to eat!) more stuff than anyone else on this planet. Therefore, I should be rightfully saying the Western diet is regretfully limited (by comparison, no derision intended.)
@gmurphy: Sure brother, I DO enjoy a burger delicious taste as anyone once in a while..with a teeny disquiet about its healthfullness in the long run. As for the toad poison thing, like fugu fish, it's all in how you prepare them. Humans have tried (and died!) to find ways to make a thing to be edible and tasty. Google perhaps? I ate tons of poisonous toads and i am still here *harassing* you lot!
@alfie_null: Intensive raised farm chicken is tasteless. Over boil them and they turn the consistency of cardboard in hot water. Try (true)free range chicken and you'll see the meat are so..
Skepticus
2.7 / 5 (7) Jun 14, 2012
(cont.)
different. A bit of chewy tendon, a bit of fat, all indication of muscles had been working instead of atrophied and force-fed in a cage. As for vegetarian foods, I do agree, as i do eat everything!
@kaasinees : that's a bit unkind mate. Humans are omnivore. We can't expect our desires and our physiology to follow either one or the other. Just don't discriminate and be flexible, listen to your body needs.
PCB
3 / 5 (1) Jun 18, 2012
As evolution favors "survival of the most adaptable", Asians may one day supersede your race! So, 'better start eating "everything under the sun" too! Oh, and be sure to over-cook those squid innards or risk having a mouthful of live squid sperm painfully inseminate your mouth and throat.

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