insects

excuse me if i asked this before but could a native spider bite and kill a fish, lets say one fell in could it pose a threat

I doubt it very much bro. What are we talking about here? Giant house spider Vs neon tetra or what?

Jay

Viperbot wrote:

Giant house spider Vs neon tetra?

lets say for instance, yes, would the spiders fangs penetrate a fishes scales or mouth resulting in death or serious injury

A friend in Dublin had a problem with feeding a spider to a fish,I think it bit it in the mouth or throat,causing problems,I just cant recall exactly what happened though.

Oh, I thought you actually had this scenario playing out. I dunno, I guess if you were to catch a small fish and place it in the web of a big spider like that, then yeah it would probably be toast. If the spider was to fall into the water though, I think it would play out differently. I cant see the spider going for a meal when its probably tring to escape drowning. Most likely the fish would nip at him instead...

Jay

Native spiders are venomous.....but I doubt that there is much in the way of LD50 toxicological data for wolf spider venom on the various tropical fish.

igmillichip wrote:

Native spiders are venomous.....but I doubt that there is much in the way of LD50 toxicological data for wolf spider venom on the various tropical fish.

Indeed...

Jay

Some of the larger native spiders are capable of biting large prey, including humans. There's also at least one (dysdera crocata or something like that) built to penetrate the armour of woodlice, which would be well capable of penetrating fish scales. All spiders are venomous and can cause damage equivalent to a wasp sting.

Hypothetical - would have thought lotto style odds of it happening

I know someone that fed a big spider to a large African cichlid (C. Moori) and next day found the fish dead. Whether it was a bite or not is another thing..

I think most common spiders would just drown maybe? Smaller fish would come in for a nip, and the spider is hardly in a position to combat, being in water, as jim said, lotto odds, I reckon a spider will just drwon and end up fishfood

Mark

Look at this

if i see a house spider (the bigger meaty looking ones) i will catch it as quick as possible (wife's screams are unbearable) and throw it to the fishies. they dont drown they can walk on water.
and either the archer fish, severum or rainbow have all eaten them with no ill effect. very quickly too, they like em better than crickets or shrimp.

Jim wrote:

Some of the larger native spiders are capable of biting large prey, including humans. There's also at least one (dysdera crocata or something like that) built to penetrate the armour of woodlice, which would be well capable of penetrating fish scales. All spiders are venomous and can cause damage equivalent to a wasp sting.

Hypothetical - would have thought lotto style odds of it happening

I've been stung by a wasp, and it hurt......but believe me, I would not like to get nabbed by anyone of many of my spiders......the damage would be a lot more (and more painful) than a simple wasp sting.

Hi Ian,
I guess you know more about different insect/arachnid toxins than I do, but I only know two people bitten by spiders in Ireland and they compared them to wasp stings. Perhaps it was due to the volume injected?

One did say that his arm swelled up quite a bit for about 24 hours

is there much danger of being nabbed by Irish spiders?

i never knew natives could bite, i knew there was fairly potent venom but not capable of pircing skin

Maybe i am barking mad but I have worked on the docks and currently work for a coffee roaster and have seen some big ass spiders in both places. What was native 20 years ago could be very different to current spiders here.
I was sitting in an office a couple of months ago and something caught my eye running accross the floor. I thought it was a mouse. When the screams started I went over to investigate and had to get a big cup to trap the spider.
Instead of squashing it I put it outside. God knows what species it was.
Point is do we really know whats living here any more with all the shipping from foreign climes.

funny you should say that when i worked dunnes back in the day the lads on the fruit & veg opened a box of bananas and as they were packing them out came one huge spider! they caught it in a little plastic conainter and the DSPCA were called who then took it away

i can picture the spider screaming "you dirty snitches" as he's getting cartered off in cuffs

@Pat…there is always a possibility of exotics being brought in on cargo. Maybe such sightings are best reported to the appropriate authorities (and you could always contact the Herpetological Society of Ireland as we also cover Tarantulas).
As for exotic spiders becoming naturalised? That is a bigger discussion, and one which would greatly concern me.


For any venomous animal, there are a number of things that need taking into account.

Firstly, we consider that every substance is poisonous…..it is the dose that counts (a basic tenant of toxicology).

All venomous animals are hazards; the risk of envenomation is a factor that determines how dangerous a situation is.

We need to consider….
The actual toxicology of the venom. The LD50 is a value used to indicate the dose that will kill 50% of all test subjects (and that is cited for a specific species of test subject)…..the lower the LD50, the more potent the poison is to the test subject.

Within that, different substances act on different animals in different ways; and different animals have different ways of dealing with a substance. If something can be detoxified and excreted rapidly then that may lower the potency.
All of that indicates the level of the hazard.

But for anything to do any harm it needs to get into the body of a victim.
So that leads us to the questions of Risk.

If the venomous species has no way of delivering venom to a victim, then the risk of envenomation is reduced (but that does not alter the level of hazard). Eg if the venomous animal is on the moon then it is no risk to me (but it is still a hazard), if the venomous animal has fangs unable to penetrate my skin then the risk of envenomation is reduced etc etc

The behaviour of a venomous species also comes into play……is the spider more likely to run away than stand and fight? Is it an aggressive spider? Does a potential victim frequently come into contact with the venomous species?

Venom is an energy expensive thing; a spider needs to conserve it as much as possible.
As such, many spiders will only use their venom if absolutely necessary…..in such cases a ‘bite’ may be a dry bite warning (if the fangs penetrate, then it could hurt).
Spiders are very good at determining, to quite a level of precision, the amount of venom to inject. (a bit different to the case with bees).

A large volume of venom of low LD50 is not a promising sign for a victim injected with such venom; a very small volume of venom with a very high LD50 is much more promising.
That is where Danger comes in….we have a Hazard, then individual situations indicate a level of Risk…..if the Risk is high and the intrinsic potential for doing harm is high (eg potentially fatal substance) then the Danger is high.
If the hazard is potentially fatal yet there is zero chance of contact then Danger is zero (eg me on earth with the spider on the moon).

For our native spiders, there is little danger to us….but that does not mean that they do not pose a danger to small animals.

Now, some spiders have venom mixes that contain a substance that stimulates the pain receptors (a bit like having an intravenous injection of the hottest vindahloo curry)……now they hurt yet may have no medical significance other than pain.
And others are extremely hazardous and extremely dangerous (if in contact with them)….but that tends to be reserved for exotic species.

ian

ah come on now Ian, spiders on the moon? lol no i get it, so i have the chalk board out and i'm deciphering all the possibilities and i got E=MC2? after a bit of back tracking and altering i came up with the spider would fall into the tank the fish would strike and the spider might give him a bite as a warning but could deliver venom so depending on the size of the fish, type of spider and speed of the strike he might be lunch, so the mythbusters answer is, it's plausible

dar wrote:

ah come on now Ian, spiders on the moon? lol no i get it, so i have the chalk board out and i'm deciphering all the possibilities and i got E=MC2? after a bit of back tracking and altering i came up with the spider would fall into the tank the fish would strike and the spider might give him a bite as a warning but could deliver venom so depending on the size of the fish, type of spider and speed of the strike he might be lunch, so the mythbusters answer is, it's plausible

I decided not to include any quantum mechanics calculations outlining possible spatial distribution of electrons in venom (especially the high-spin vs low-spin quantum state and relative volume of Iron) and then limiting that to the most probable distribution.....but the offshot to the question is Yes, it is plausible (given the variables described in your post Dar).

and.....I like the 'toxin-on-the-moon' analogy for 'low risk' situations.

igmillichip wrote:

I've been stung by a wasp, and it hurt......but believe me, I would not like to get nabbed by anyone of many of my spiders......the damage would be a lot more (and more painful) than a simple wasp sting.

@ Ian, I've googled this a bit now - a lot of work done in the US where one of our spiders is known as the hobo spider and blamed for a lot of biting. However, most sites claim very little harm, with a lot of comparisons to wasp stings. Are your spiders exotic rather than native species?

Also - many scientists have had trouble trying to provoke the spiders to bite, so it seems pretty rare for them to bite anything larger than their normal prey. Maybe the original scenario is "possible" rather than "probable" - don't know where "plausible" fits in . . .

@Jim, I have to take care with spiders. J (my OH) and I have quite a nice selection of exotic spiders....I treat all with caution.
As for native spiders.....they are big problem for me as well. I have a number of small animals (frogs, eg PDFs, pygmy chameleons, minute geckos) that might try to eat a spider. So I need to make sure all vivs are clear of spiders. Not sure if these animals would actually attempt to eat a spider....but I take no chances.

Possible vs probable vs plausible.....hum, well I guess that everything is possible, but the world works by weighted probabilities IMO. It is possible that when we step outside the front door that our first step will be onto the moon, but the probability of that happening is almost zero (so it doesn't happen); I see that Dar quote Dar quoted E=MC2, so that leads me to think of the notion of every step being an unavoidable consequence of the preceeding one (maybe weighted probabilities????).

On the subject of probabilities......often the method of scientific investigation gives incorrect answers simply because we are observing an event. An aggressive spider may not attack a large human proding at it....as maybe the spider things that there is no benefit in wasting energy.

gobble-dee-gook

if a native spider bit you and you had a reaction its similar to some people having serious allergies to wasp stings

i was bitten when i was younger by a big ass spider in england, no reaction just a pinch as he bit and i only feel a little sting from a wasp bite and it looks like a small red pimple for a day

those who HAVE had a reaction from a spider bite, how do they react to wasp stings? in other words, compared to a wasp sting that is only lethal for insects and just gives us an irritation, if a spider doesn't even give the average person an irritation and only puts a fly into a state of unconsciousness i very doubt the potential it has to kill a fish, especially as freshwater fish live in rivers and lakes, around these are ecosystems of which spiders would be a part of, some more dangerous than our own natives, and these spiders may fall onto the water and be eaten by said fish. if a fish wont eat it then it wouldn't feed on it in the wild, my archers specifically hunt (often poisonous) insects including very dangerous spiders in south america and the are usually first to the spiders i throw in my tank
the rainbow fish eats insects from the surface in rivers/lakes in australia home to the most dangerous creatures and my rainbow has no problem snapping spiders from the surface
severums from south america will also have insects falling on the rivers and will, when possible, eat said insects. and so too does my severum

Hold on wait



You certainly don't have to convince a Rainbow to eat a spider:)



I think what is implied in previous posts is that even with those fish in the wild, some may die from this feeding although death from eating spiders may be very rare indeed, thus it matters not, lots of those fish in their native waters, but in your tank if you get unlucky, your one or one of a few fish might die and it is a risk some are not prepared to take.

Takes Bertie Bassets matey:)



Mark

i do recall watching a documentary where this little spider (i think his name was incy wincy or something simular but that is not relevant) who lived under water and sure the little scamp would come up and trap air and scurry on back down to his little safe spot where he was successul in catching and eating fish

@joey…..gobble dee gook, I think not. Despite any tongue-in-cheek science humour (and I do see science as being one big topic for humour anyway), we can never ignore the difference between possibility and probability (and I will, for the sake of sanity not go into the science of that as I end up cackling when even starting to type about science!!!!)

…..we also know that poison dart frogs eat highly toxic insects....the PDFs manage to avoid the toxic effects, yet most other animals would not be able to avoid being poisoned.

Each venom has differing effects on differing animals and on individuals.

As a Hazard, venom’s hazard level is not necessarily inherently dependant upon a single individual’s reaction; but an allergy does recon within the Risk and Danger aspect (that is why proper risk assessments are important).

The standard measure of toxicity is the LD50….but that only tells us the amount needed to kill 50% of the test population, thus, inherently, indicating that we need to recognise that a single given dose may or may not kill a given specimen.
If a substance has a low LD50, then, in my opinion, it would be rather ignorant to listen to anecdotal stories of someone getting zapped and surviving and using that as an example to say the substance is not as dangerous as it is made out to be.

Allergies or other types of applicable hypersensitivity are a set of factors that complicate the potential danger of an envenomation.

I recon that my saratoga's regular jumps after dark are for catching spiders and other forms of inverts from above the water, but that doesn't mean to say that all fish would be safe to eat a spider.

A sub-lethal dose of venom doesn’t mean that no harm is done.

Do we really have enough info about long-term sub-lethal doses? The answer is no, and LD50 data have little role in such scenarios, but it is a focus of more and more attention.

ian

Presumably there are different degrees of reaction even within a given species(hence Ians LD50, some test subjects die, some live).

Joey has almost no reaction to wasp stings. I was stung twice in the chest a couple of weeks ago. It swelled up and hurt for about 8 hours, but nothing more. Some people die.

As Mark said, do you want to risk that your 1,000 euro arrowana is the one that will die? Has a tropical fish evolved any tolerance on the venom of temperate invertebrates (or are they the same.) Would you feed wasps to your fish?

I try not to feed anything that may possibly harm or cause discomfort to my fish, or even permanently impair it in some way as it would be hard to tell if one of my fish was say blind in one eye, shorten its lifespan or lastly kill it.

So if I am not sure that spider venom of a certain available spider for food is safe or not for my fish to consume I prefer not to feed it. I even checked before feeding crane flies even though I assumed them to be safe.

Have found many spiders as you do, but one big black horrible on in the hallway, man it was ugly and quite big, put it outside, never even thought of feeding it to the fish.



Mark

The subject of selective toxicity is a fascinating area.

There are some interesting variations and some equally interesting questions about selective toxicity.

Even if we take one of the most toxic substances known…..tetradotoxin from poison dart frogs and some fish (eg puffer fish).
Tetradotoxin is a pretty ubiquitous poison, yet how do poison dart frogs and puffer fish not succumb to its action?

In fish it appears as though the tetradotoxin is produced by bacteria in specialised cells, but the jury is out with respect to poison dart frogs….in that there is a case that the frogs may obtain it or a pre-cursor of tetradotoxin from dietary sources.

So, could a poison dart frog or other amphibian (and it would have to be another much larger amphibian) having tetradotoxin swallow a tetradotoxin laden puffer fish and survive?
And what about vice-versa?

In toxicology, it is not just what the poison does to the body that counts…what the body does with the poison also counts.

Think about heavy drinkers versus normally non-drinkers on a heavy booze night. The acute toxic effects of alcohol are probably going to be more noticeable in the normally non-drinker, but the chronic effects of alcohol in the heavy drinker will be added to.
There are differences between acute, chronic and cumulative poisoning…..different outcomes and illness.

In insects, the insecticide malathion is, as a molecule, not particularly toxic….because the insect can ‘detoxify’ it…..Aaaagh, but wait….that’s the problem and that is why malathion is used as an insecticide:
the insect’s attempt to detoxify malathion produces another compound (malaoxon) that is deadly to the insect and one which the insect cannot detoxify rapidly (or at all)
In humans, we have a different detoxification system wrt malathion….hence the acute problems of malathion are low risk (although there is concern about chronic exposure).

Much of the work in toxicology is very ‘now’ and knowledge is increasing at an alarming rate. When I first started working on frog toxins (for example), I could probably name and draw all compounds known at that time…..but nowadays, I need my database to help me keep up with just the count of the number of toxins.

I love toxiciology…..