Apple Snails in Australia (or not) and Snail Sex Pheromones

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Apple Snails in Australia (or not) and Snail Sex Pheromones

Postby flaringshutter on Thu Nov 08, 2007 9:02 pm

I found these two articles today, thought they might be interesting to some of you too.

http://www.abc.net.au/rn/science/earth/ ... 108695.htm

Saturday 04/03/2000

Golden Apple Snail

Summary:

The Golden Apple Snail which is originally from South America was introduced into Asia through the aquarium trade. It was then also promoted as a potential food source for humans. Now it's in plague proportions in many ricefields and could find its way to Australia.

Details or Transcript:

The Golden Apple Snail begins life as bright pink eggs that are laid on the edge of waterways, and grows into an adult the size of your fist. It resembles the Golden Delicious apple, hence the name. And it has a very healthy appetite, particularly savouring young rice plants.

This Golden Apple Snail has Dr Geoff Baker, from the CSIRO quite worried, and Lynne Malcolm found out why.

Geoff Baker: The Golden Apple Snail’s origins are in fact in South America; it lives in the swampy lands to be found in Southern Brazil, the borders with Argentina, Paraguay, that part of the world. In about 1980 the animal was introduced through the aquarium trade into Asia, in fact into Taiwan because it’s a pretty snail, and people liked having it in aquariums, and it feeds on the scum that forms on the inside of a glass tank, and so it had its uses as well as being attractive. And all went very well, and then somebody got the bright idea that these things might, because of their size and their rapid growing and huge reproductive potential, might be an ideal thing to rear as a source of food, high in protein content.

There were in fact government programs set up in Taiwan and the Philippines to encourage this, and the way things went, and people mass reared them, set up farms, and then suddenly they realised that nobody really liked the taste of them, which was absurd in hindsight. But that’s the way it happened. And these farms were abandoned; the snails escaped into the waterways and spread around through the Philippines, Taiwan, and became major pests of rice. And that scenario has been repeated in several countries, such that now the snail has spread all the way from Japan down to New Guinea and Malaysia. It’s through Thailand, throughout Vietnam, through Laos, Cambodia, into China, and is now a big problem.

Lynne Malcolm: So the snail actually feeds on the rice plant itself, is that the main problem?

Geoff Baker: That’s the overt main problem. It feeds on the young seedling rice. It won’t damage a mature rice plant, but feeds on the very young seedling rice and can cause huge damage, very, very significant damage. That’s one problem, that’s the thing it’s most notorious for. But you can’t have billions of snails in the waterways, they’re not just in the rice paddies, but the waterways that supply the native waterways, that supply the rice paddies. And so the snails are riddled throughout those habitats. Really we have very little idea of what damage it might be doing, but because it’s such a catholic animal in its taste, it’ll feed on all sorts of vegetation, it must be doing huge environmental damage there. It’s competing with native snails, and some of these native snails in Asia look very similar to the Apple Snail.

What then happens is that there are tonnages of pesticide being used by the rice farmers throughout Asia to try and combat the Apple Snail. They don’t recognise the difference between it and the native snail, so any native snail then gets pesticided as well. The snail has another insidious problem associated with it: it harbours parasitic worms which are of significance in human health. There’s so many snails that when they die they get crushed into the paddies, the snail shell edges are sharp and cutting the rice farmer’s feet when they go in there in bare feet. And so it’s a very general problem, not only from an agricultural point of view, but also from an environmental point of view.

Lynne Malcolm: So why are you in Australia in the CSIRO concerning yourself about the Golden Apple Snail?

Geoff Baker: This pest is sitting on our doorstep, and with all the best will in the world in terms of quarantine interception, eventually we’re going to get this snail in Australia. My concern and others, is that we’d better know something about this problem before we get it. We can predict through climatic matching, this thing is not just going to stay in South East Asia, and if it gets into Australia we expect it will get into our waterways across the north of Australia and down the East Coast of Australia. It should be a threat to our rice industry, which is essentially based in Southern New South Wales, so there’s an agricultural issue for Australia on the horizon, but also an environmental issue, that if this thing gets into Australia, into our waterways, we’re worried about the environmental impact that it will have, and the environmental consequences of trying to control it.

Lynne Malcolm: How would it end up in Australia, would you imagine?

Geoff Baker: It can come in as eggs or as snails on crates, or in produce by accident. Or it might be brought in by deliberately by some not too wise person. But it can slip in very easily.

Lynne Malcolm: So what type of work would you like to do now on the problem?

Geoff Baker: What we’d like to see done is a lot more work on the basic biology of the animal in Asia, so that we understand the animal better than we do, and maybe in doing so, find the cracks in its defence in terms of finding ways to control it. Now there is some work going on in Asia, it’s hardly that relevant for protecting our waterways. The other opening that we should be looking at I believe, is looking at the animal in its native South America. In South America we know virtually nothing about its natural enemies; what sort of biological control agents might be living in South America adapted to this snail that we could make more use of. We should look and see if there are options there that we could safely apply, both in Asia and also be prepared in Australia.

Lynne Malcolm: So how difficult is it to get funding to do work on something that’s not yet a problem in Australia?

Geoff Baker: It is difficult. It’s pre-emptive research; by definition it is difficult. All you can do is say Look, we have a threat coming, and we should be prepared. At the moment we can’t find that funding. There are agencies that are interested in the topic, but there are higher priorities and few dollars. So all I can do is get us as prepared as we possibly can be in the eventuality that this problem does come.

Guests on this program:

Geoff Baker
Senior Research Scientist
Division of Entomology
CSIRO, Canberra

Reporter:
Lynne Malcolm


-------------------------------

And: http://mollus.oxfordjournals.org/cgi/co ... t/eym027v1


A WATER-BORNE SEX PHEROMONE AND TRAIL FOLLOWING IN THE APPLE SNAIL, POMACEA CANALICULATA

Mari Takeichi1, Yoshio Hirai2 and Yoichi Yusa1,
1Faculty of Science, Nara Women's University, Kitauoya-nishi, Nara 630-8506, Japan; and 2Sena 7-chome 12-11, Shizuoka 420-0911, Japan


Correspondence: Y. Yusa; e-mail: yusa@cc.nara-wu.ac.jp

Abstract

We investigated whether individuals of the apple snail Pomacea canaliculata were attracted by conspecifics or follow mucus trails of other individuals. The snails' behaviour was studied by a series of choice experiments in a T-maze and in Petri dishes. Both males and females chose the side with a snail of the opposite sex significantly more frequently than the control side without a snail. Males were attracted by water conditioned with females more frequently than unconditioned water, whereas females did not show a preference for male-conditioned water. Moreover, juveniles were not attracted by water conditioned with a male, a female and a juvenile. These data indicate that males were attracted by female odour, which contains one or more water-borne sex pheromones. In addition, both males and females follow mucus trails of snails of the opposite sex. Since females also followed trails of females, the function of trail following is not necessarily related to reproduction. In these experiments P. canaliculata did not distinguish the direction of the trail.

(Received 10 March 2007; accepted 12 July 2007)
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Postby jonfr on Fri Nov 09, 2007 12:10 am

They must be meaning cana, not brigs. Far as I know, cana eats plants, while brigs don't.
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Postby pbgroupie on Fri Nov 09, 2007 12:24 am

You're right, GAS is the cana.
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Postby Pollux on Fri Nov 09, 2007 1:00 am

thanks flaringshutter :). i have found several papers from the CSIRO about GAS done after 2000 so they must have gotten funding eventually. i found this article a while ago that says that there was an infestation in Brisbane where i live at one point, but im not sure if it is true because i found no other reference to it:
They were introduced into Australia up in the Brisbane area and the most effective way to get rid of them was, they let kids in the local schools out for a day, then they went through the area and just hand picked them and then they put in baskets of whatever and then they were just smashed and killed by the adults that were with them.

http://www.applesnail.net/phpBB2/viewtopic.php?t=15939
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Postby Pollux on Mon Nov 12, 2007 2:54 am

i think now that that article i found is about GALS not GAS. i knew it was too good to be true :(.
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