my new babies

[paul fleming]

I thought hahni was only slightly more toxic than terrosus, is there an ld50 to compare the species? Are theese the only two known species of Sicarius?

I don't think there is mate.
They are doing studies on mamals now but nothing has been released so far.
I really don't think anyone can say how bad they or any other species of sicarius are until more data is available.
Not to be messed with,that's for sure.
It does seem strange that they are not on the DWA and DEFRA have no plans to put them there either.......do they know something we don't ?

 

[paul fleming]

http://www.vincelewis.net/deadlyspider.html

 

[Irene B. Smithi]

Wow, that's an exciting spider to have!! Way too much for me, but wow neat to see!!
Do you have a plan if it escapes? Could it survive and thrive in your home on the run? That would be what would worry me the most.

 

[Moltar]

Interesting read Spit. I don't know if I agree with everything he says though. He downplays the toxicity of the Sydnet funnel web, implying that its venom is comparable to that of a widow or brown recluse. It is, in fact considerably more potent than either and AFAIK stronger than any Phoenutria by far. Before they had antivenom in Australia a bite from this species quite often resulted in death.

Still, a good read.

 

[paul fleming]

L.hasselti is a lot worse the Atrax mate......I think they are all bad mind
I would also say the Loxosceles laeta is a lot worse than Atrax so he is sort of right about certain recluse spids....I know which one I don't want to tagged by given the choice.....lol......don't fancy my body parts falling off.
"According to one study, the venom of the Chilean recluse (along with the six-eyed sand spider), contains an order of magnitude more of this substance (dermonecrotic agent, sphingomyelinase D), than that of other Sicariidae spiders such as the brown recluse[4]."

Another intersting read with medical facts this time
http://www.mja.com.au/public/issues/179_02_210703/isb10807_fm.html

 

[Widowman10]

L.hasselti is a lot worse the Atrax mate......I think they are all bad mind

really? i've always thought (and read) things that implied that atrax were much worse than hasselti. are you talking effects on humans, or LD50? atrax have a slightly lower LD50 value than latrodectus. and, the effects on humans (primates) are worse with atrax. wondering what you are basing this on.

 

[paul fleming]

http://blog.hotelclub.com/the-10-most-dangerous-animals-in-australia/

http://www.australianfauna.com/t10dangerous.php

http://www.famie.com/australia/mostunusual_mostdangerous.htm

I think until we get an Ld 50 for humans......can't see that happening some how......there is no real way to say which is the most deadly.

 

[Moltar]

Yeah, i'd always thought the same as Widowman about L. hasselti vs A. robustus. From what i've read and seen on Discovery Channel, etc (and they're never wrong ) A. robustus was quite often fatal before antivenom whereas L. hasselti is, like other Latrodectus, fatal only in a very small percentage but can be extremely painful.

I think this discussion has been done before but, as you say, until we have LD50 data on humans it's all academic. If it comes down to it though, i'd rather take a hit from a Redback than a Sydney Funnel any day. Same thing with an American Latrodectus spp. vs L. reclusa (brown recluse) That Loxosceles venom is some nasty stuff! At least with a neurotoxin you know what to expect...

 

[Widowman10]

the LD50 for Atrax is the same if not lower than Latrodectus. also, consider the amount of venom injected with each spider. on top of that, robustoxin has a particularly nasty effect on primates, whereas latrotoxin does not.

latro bite - no huge deal, lots of pain. atrax bite - big deal. probable need of antivenin. i would much rather take a hit off a hasselti than a robustus any day of the week.

 

[Widowman10]

Yeah, i'd always thought the same as Widowman about L. hasselti vs A. robustus. From what i've read and seen on Discovery Channel, etc (and they're never wrong ) A. robustus was quite often fatal before antivenom whereas L. hasselti is, like other Latrodectus, fatal only in a very small percentage but can be extremely painful.

I think this discussion has been done before but, as you say, until we have LD50 data on humans it's all academic. If it comes down to it though, i'd rather take a hit from a Redback than a Sydney Funnel any day. Same thing with an American Latrodectus spp. vs L. reclusa (brown recluse) That Loxosceles venom is some nasty stuff! At least with a neurotoxin you know what to expect...

Moltar, you're right. latro bites are only dangerous with the young, elderly, and immune-compromised. robustus bites are dangerous with all.

and LD50 is great (not perfect, but great). all the tests are done on mice, which are also mammals and are very similar to humans. the effects are much closer than if they were done on say, amphibians or something else. it's a pretty good rough guess. the big difference i can see right away is if there is another chemical / toxin that is specifically designed to be nasty towards a certain group. like the robustoxin found in atrax robustus. it is geared towards primates and has a nasty effect. obviously the LD50 isn't going to convey this


EDIT:
here's some quick info on the similarities of mice and humans, since this plays into the discussion of LD50 a little:

Fourteen genes on mouse chromosome 16 are not found in humans. All the others—more than 700 mouse genes—have counterparts in the human genome, most of which are grouped together and in the same order as in the mouse genome.

In short, the human and mouse genomes are remarkably similar not only in the structure of their chromosomes but also at the level of DNA sequence.

 

[Moltar]

Thanks Widowman. I guess i'm sort of a realist in how I think of envenomations. What I tend to think of is what will the real effect of an envenomation be? A robustus is a good example; it doesn't matter if the venom is no stronger than some other toxic species (like L. hasselti) if you're being injected with 10x as much. Plus those Atrax are mean! Well, so i've heard...

I think if our country can ever get over itself and allow more stem cell culturing we may see human LD50 values (or whatever the equivalent would be called) in a few more years. These things can be accomplished by just exposing tissue to venom, right? Like it doesn't have to actually kill an organism to find the value?

 

[Widowman10]

you're right ethan. i always think of the rattlesnake and the widow. the widow has venom 15x stronger, but it doesn't inject nearly as much, which makes the snake much deadlier.

and with LD50, it is technically defined as "the amount of the substance that kills 50% of the test population of experimental animals when administered as a single dose."

so, that being said, i don't know if it would be possible to do an "LD50" on humans. you could easily observe the effects it would have on human tissue, yes, but i don't know about killing 50%

 

[paul fleming]

how about if they did an LD50 on dogs (which I do not want as I am a dog lover and ownner).
Atrax would then have a very figure.
We are humans and not mice so it is a bit different.

 

[Widowman10]

how about if they did an LD50 on dogs (which I do not want as I am a dog lover and ownner).
Atrax would then have a very figure.
We are humans and not mice so it is a bit different.

a bit yes, but mice and humans are very similar when you look at the sequences. not exact, but pretty close. and yes, certain toxins would have different effects (such as the robustoxin in atrax robustus ) when in different animals.


how bout LD50 testing on primates? now THAT would give some pretty dog-gone good results. not advocating this though...

 

[paul fleming]

a bit yes, but mice and humans are very similar when you look at the sequences. not exact, but pretty close. and yes, certain toxins would have different effects (such as the robustoxin in atrax robustus ) when in different animals.


how bout LD50 testing on primates? now THAT would give some pretty dog-gone good results. not advocating this though...

I know it sounds cruel but that is what we really need.
It could also help with antivenin for the spiders where none exists and so save human lives.
I say yes.
It is not as if we are testing lipstick or mascara on them.....which is a waste.

 

[Moltar]

I think I'll offer a counterpoint just for the sake of argument...

What do we actually gain from knowing specific LD50 values? If venom was being tested simply for the amount of damage it did to a certain tissue culture in a given time period doesn't that tell us just as much, if not more? We've already established that LD50 often has little to do with the real world effect of an envenomation by this, that, or the other species. Latrotoxin is stronger than robustotoxin yet A. robustus is a much more deadly spider because of how much venom it injects. Ditto rattlesnakes vs latrodectus. Does it actually benefit us as humans to know that latrotoxin is stronger per ml than robustotoxin when A. robustus is much more likely to actually kill you?

I'd like to see a chart or system of ratings by species that has some sort of scale for actual danger instead of this abstracted ratings system that focuses only on the venom, not on actual the effect of an envenomation. There are quite a few variables at work though so it would be a daunting task.

 

[Widowman10]

I think I'll offer a counterpoint just for the sake of argument...

What do we actually gain from knowing specific LD50 values? If venom was being tested simply for the amount of damage it did to a certain tissue culture in a given time period doesn't that tell us just as much, if not more?

yes, and no. while that info could be helpful, i still think you need to test the organism itself, and not just tissue. it would interesting and helpful to see what the venom does to certain tissue, but then how would that venom then affect the rest of the body, i.e. circulatory system, nervous system, etc. that's a big reason behind testing the whole organism and not just a tissue sample. is that what you were getting at, maybe?

We've already established that LD50 often has little to do with the real world effect of an envenomation by this, that, or the other species. Latrotoxin is stronger than robustotoxin yet A. robustus is a much more deadly spider because of how much venom it injects. Ditto rattlesnakes vs latrodectus. Does it actually benefit us as humans to know that latrotoxin is stronger per ml than robustotoxin when A. robustus is much more likely to actually kill you?

i'm sure there's other things, but i think we as humans are really interested in how strong venom can be, and which species have stronger venoms. maybe that helps when distinguishing prey types and observing how venom makeup affects different species (this can come into play when learning about the ecosystem and how different predators will prey on spiders, and how the spiders have evolved/adapted their venom to counteract the predators. just a thought).

now what i would like to see, would be an LD50 number, coupled with an average dosage number (how much venom is usually injected in a full bite). those 2 numbers coupled together could give us some pretty sweet results. cool?

I'd like to see a chart or system of ratings by species that has some sort of scale for actual danger instead of this abstracted ratings system that focuses only on the venom, not on actual the effect of an envenomation. There are quite a few variables at work though so it would be a daunting task.

again, i agree with you, but read the paragraph right above this one. if we were to implement a system such as this, maybe it would take out the subjective opinions and whatnot. that's where many of the crazy "most dangerous" lists come from is peoples' subjective opinions. and that's why there's so many lists with different animals and wrong orders.

 

[Richard McJimsey]

I am mate.

Sorry mate, but based on what you've posted on here, and the countless occurances of ridiculously incorrect information, I'd say it's only a matter of time before you get hurt.
I won't even touch on the subject of LD50 tests done on primates being "needed"...
Nice spiders, though! :clap:

 

[paul fleming]

Sorry mate, but based on what you've posted on here, and the countless occurances of ridiculously incorrect information, I'd say it's only a matter of time before you get hurt.
I won't even touch on the subject of LD50 tests done on primates being "needed"...
Nice spiders, though! :clap:

Merry Christmas to you as well mate......thanks.
I won't wish the same to you.
I hope you never get hurt and spend the rest of your time enjoying life,your family and kids.......like I wish to do.
Anyway,they are only monkeys so can't see what the problem with testing spider/scorpion venom on them is.
Better them than than good old human beings.

 

[Moltar]

now what i would like to see, would be an LD50 number, coupled with an average dosage number (how much venom is usually injected in a full bite). those 2 numbers coupled together could give us some pretty sweet results. cool?

That makes a lot of sense. Like (Venom quantity) / (LD50)="danger quotient" or something?

Funny, another thought I had just now is how futile these types of measurements really are in the real world. It's pretty much a given that the local population already knows that this organism or that one is dangerous and to avoid them. The people that live with these creatures usually know enough about the danger to keep themselves alive well before some scientist shows up and collects some specimens for LD50 testing.