Talk:Black widow spider

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Black widow spider is included in the 2006 Wikipedia CD Selection, or is a candidate for inclusion in the next version. Please maintain high quality standards and, if possible, stick to GFDL-compatible images.

There are spiders called "brown recluse" spiders, but none called "black recluse" spiders. Somebody must have either been confused or must have picked up some misinformation from the mass media, so I removed the sentence that questioned the relationship between black widows and black recluses. P0M 03:46, 12 Mar 2005 (UTC)

The hourglass marking on black widow females is most commonly red but doesn't have to be, nor does it have to be an hourglass shape. The two halves of the hourglass may be separated into 2 spots. This source from Ohio State Univ. can verify: http://ohioline.osu.edu/hyg-fact/2000/2061A.html User:Jdoty 11:45am, 16 May 2005 (EST)

The article fails to represent a recent taxonomic shift in how black widows are classified. In years past, there were two recognized species of black widow; the American Black Widow (L. mactans) and the Mediterranian or European Black Widow (L. tredecimguttatus); this excludes other widow spiders such as the red-back and the brown widow. Recently, the American Black Widow was reclassified into 3 species: the Southern Black Widow (L. mactans), the Northern Black Widow (L. variolus), and the Western Black Widow (L. hesperus); all of which probably should be described in a page entitled "black widow". User:EngineerScotty 09:49, 16 Jun 2005 (PDT)

There already is an article called "widow spiders" that lists a very large number of Latrodectus species, including the ones you mention. There have been many taxonomic changes for spiders in recent years and the specialist who has helped the Spider article greatly by doing the taxonomic categorizations has consulted the most up-to-date materials. It is not uncommon for terms like "bananna spider" to have alarmingly different meanings depending on who is using the term, so it is better to base everything on the taxonomy recognized among scientific researchers. Wikipedia kind of asks for trouble, however, because people frequently start articles with the English names and then resist their being renamed. I'll look at the Black Widow article. The people who encounter L. hesperus might be misled if they checked "Black Widow" and discovered that it didn't look like the one they were thinking of picking up while "posing" it for photographs. I'll have a look at the article. I think a "see also" would be the most appropriate way to handle this problem. Too bad nobody has provided pictures of any of the other Widow species. P0M 06:20, 17 Jun 2005 (UTC)

The three species of black widow in the US are mostly indistinguishable from each other (especially to the untrained eye); there is more intra-species variation (depending on sex and age of the spider, in particular) than there is inter-species variation. You'll probably have to dig deep in the literature to find a list of differences among the three species, other than the geographic region where they are found (which does overlap). My suspicion is that the black recluse and violin spider pages (the latter of which I've disputed) really refer to some morphilogical variant of L. hesperus that has been shown to be a western widow; rather than a different species of spider altogether. Unfortunately, while much modern research material is catalogued and available online; much older material is not. (The other possibility is that they refer to one of the false black widows, most likely S. grossa). EngineerScotty 11:49 17 Jun 2005 (PDT)

I'm of the opinion now that the Black Recluse/Violin Spider may very well be an old classification, restricted to some entirely local study, that has since passed completely into obsecurity. What I'd grown up taking for granted as a normal part of the area's biodiversity now seems to be completely absent from anything I can find on the web. As the description on the page says, the females of this species are back or very dark grown, and have a vaguely violin-shaped (or irregular hour-glass-shaped) red or yellow mark on the bottom of the abdomen. So this would only be a very slight morphological variant, with the exception of the males, who more closely resemble the brown recluse. Though their inclusion in the article should be removed, as the form of the males is original research on my part (I merely interpreted the partially-eaten males (I assumed males, as they had bulbous mandibles, which is an indicator of masculinity in many, many species) that I found in the distinctly widow-like webs of these "Black Recluses" or "Violin Spiders". So, any confirmation I've managed to get on these critters, upon reflection, seems entirely in the realm of original research -- and what's worse, is some of that original research is based on circumstantial evidence.
This does beg the question, however: What are these venomous, widow-like spiders commonly found in Southwestern Washington State, when black widows "don't exist here"?? The distinctive body-shape, the dark color, and the red spot on the abdomen are all tell-tale signs, which I am more sure of than anything I've ever been sure of before, are characteristic of this species as well. Perhaps just some as-yet undiscribed (or previously described and forgotten about) subspecies of the black widow?
There's other issues, but they can wait until later. I'm now determined to figure out what this spider is. --Corvun 02:44, August 3, 2005 (UTC)

I am content to listen to the specialists who have solid credentials in this field. I have seen differences of opinion on nomenclature, and people whom I've written to when trying to identifying some same genus different species tarantulas tell me that the only way you can know for sure is to examine the genitalia under a microscope. If the key won't fit in the lock the mating won't occur, and the inability to make babies is the rule of thumb for species differentiation. (Actually, the "what is a species" question is more complicated than that. Sometimes creatures that are regarded as belonging to different species can mate and at least produce "mules" -- and sometimes the young are capable of reproducing. Much to my surprise I have learned that some cross-genus mating produce viable young -- but I think those are all plants. Anyway, if two kinds of spiders can't mate because "it won't fit" then there is no question of whether they belong to different species.) I think the specialists are well aware of the difference between two species and two subspecies, and our job is to report "the state of the art" research, not to go off on our own. P0M 20:33, 17 Jun 2005 (UTC)

Agreed. EngineerScotty 15:06 17 Jun 2005 (PDT)

It says that the female black widow "often" kills the male. Is this true? I've looked at many pages on the Net that imply this is a myth, or at least the black widow rarely kills the male.

Valid point. Almost all spiders will kill and eat conspecifics, some even when they are still very small. That fact leads to some special characteristics of various Genera of spiders. For instance, different species of spiders have different ways of identifying themselves as potential mates. The jumping spiders perform a special dance, and the chelicerae of one genus is specially modified so that the male spider can immobilize the chelicerae of the female, thus preventing her from biting if she feels like a snack in the midst of intercourse. There is one Genus in which the male spider removes one pedipalp (which is the body part that is inserted into the genital cavity of the female) to lessen the burden of weight (that kind of spider's male pedipalps are huge and heavy), and then while they are mating the female breaks off the other pedipalp while it is still inside her -- and eats the rest of the male spider. The female widow spiders sometimes eat the male spiders after mating, but I'll bet nobody has every done a statistical study to determine how often this happens. P0M 13:19, 19 Jun 2005 (UTC)

Rich Reynolds

Contents

[edit] How long do the males live?

The article is somewhat confusing on this point - perhaps someone can offer some clarification. "The female live on for 180 days after maturing, while a male only lives on for another ninety days"

(1) Please sign your postings.
(2) New stuff should go at the bottom. Otherwise it's like to get ignored because people won't reread the "old" stuff at the top.
(3) The listing of precise numbers of days is a bit silly. Nobody's days are numbered to that degree of specificity, unless God keeps busy making individual termination dates. I don't have a book on hand that states what their life span is. I know from personal observation that the adult females winter over and that probably means that they begin laying new clutches of eggs as soon as the weather is warm enough. Female spiders, like bees, can keep the semen from a mating safe in special receptacles in their bodies, and release the sperm to fertilize eggs when the time comes. So it is possible that the early egg masses are fertilized with sperm stored from a mating or matings of the previous summer. That would mean that they might do very nicely during the spring without males to mate with. Early hatchings would provide a fresh supply of males for matings to occur later in the summer. So a three month difference in theoretical life span might have something to do with the females wintering over and the males dying in the fall -- but that is all speculation on my part. Unfortunately, whoever wrote that part did not leave us any citations. Google may provide a lead to something on the University of California at Riverside site, or some similar dependable site. Give it a try. P0M 06:04, 19 March 2006 (UTC)

[edit] A species made in the bowels of Hell

After I saw a huge black spider on the wall of my basement bathroom last night before I turned in (wish I hadn't gone in there -- turning on the light was a terrible move), I checked this article's pictures and descriptions. All I know is that it was big and black, I'm totally scared of spiders (especially ones as big as that one), and that I'm just even more creeped out than before. >>

You didn't say where you live. If you saw a black spider on the wall, it in all likelihood was not a black widow spider. The only dangerous spiders in the U.S. that are black are the black widows. (They generally have a little red too.)

The males widow spiders wander around a bit looking for mates, but they are not dangerous to humans. The females establish a web as soon as they can after they leave their mothers, and they're about like us. If they have a home they are not eager to move somewhere else unless it gets swept away in some disaster. If they do get knocked off their web they are pretty helpless because they can't move very fast on the ground and they can't see very well either. If that had been a black widow it would have been moving upward at a slow but steady rate, looking for some safe crevice to hide in until it could get itself together well enough to think about building another web. If you live in Florida, Southern California, or maybe some of the other states in the southern tier -- or Japan, Australia... you might have seen a Huntsman (if it was very big). But they are generally brown. I am raising a couple of them now, and they run like hell if anything gets too close to them for comfort. If the spider in your basement was large and black you probably saw a big wolf spider, although they generally don't like vertical surfaces too much. But the spiders that like the insides of houses (which don't really include black widows) are all generally pretty dark in my experience. When I see one in my house I always try to catch it so that I can photograph it. They always run the other way. They never want to bite me. If you saw a creature the size of the Empire State Building bend down and try to drop an open dumpster over you, what would you do?  :-)

I've been playing with spiders for 50 years, and the only one that ever bit me did so because I unintentionally pinched her between the folds of skin in the palm of my hand. (It was my all-time favorite kind of spider too. But I was hurting her, so she had only one way to tell me to ease off.) You probably have heard of the infamous tarantula spiders that live near Tarentum in Italy. The legend says that if one bites you you will die unless you indulge in wild dancing -- and all your neighbors have to pour a libation and help you dance, of course. A famous naturalist in the 1800s wanted to know what would really happen if this kind of spider (officially named Lycosa tarentula, wolf spider from Tarentum) would bite him. He tried the whole rest of his life to get one of these fearsome creatures to bite him, but he never succeeded. It isn't recorded whether he ever danced the Tarantella despite failing to get bitten. ;-)

When people do get bitten by spiders (except for the genuinely aggressive kind that live around Sydney, Australia), it is generally because the human has either grabbed the spider by mistake, has rolled over on it while sleeping. or has put on an article of clothing that has lain on the floor for so long that the spider has moved in and then finds itself trapped. Black widows generally make their webs under a box or something that has gotten turned over in your back yard. So a bit of care can protect you quite well. P0M 07:16, 3 August 2005 (UTC)

[edit] Widow's Web

How about adding something on the black widow's web, which is very disorganized in structure as compared to most common spiders? It might help people to identify them.

The widow's web is actually more organized than that of most common spiders. It is only disorganized in comparison to orb webs. Every strand is placed in a widow's web for a specific purpose, and they are placed very specifically. The appearance is, of course, disorganized,; however if you were to look at any complicated structure with no understanding of how it functioned it would appear disorganized. For instance, imagine the inside of a bee's hive or an ant's nest: how disorganized it would seem if you did not understand anything that went on in it. I do agree with the identification, however. I find widow webs in the day, when the widows are in retreat, and I wouldn't even know they were widow homes if I didn't know what the webs looked like. There's another arguement for the organization- if they were not organized, how would you recognize them?

[edit] Enough citations?

"Black widow spiders live in temperate and tropical zones (McCorkle, 2002). They typically prey on a variety of insects, but occasionally they do feed upon woodlice, diplopods, chilopods and other arachnids (McCorkle, 2002). When the prey is entangled by the web, L. mactans quickly comes out of its retreat, wraps the prey securely in its strong web, then punctures and poisons its prey (Foelix, 1982). The venom takes about ten minutes to take effect, meanwhile the prey is held tightly by the spider (Foelix, 1982). When movements of the prey cease, digestive enzymes are released into the wound (Foelix, 1982). The black widow spider then carries its prey back to its retreat before feeding (Foelix, 1982)." I don't know the proper form, but this seems a bit misused. Themightychris 09:56, 30 January 2006 (UTC)

Well, it's not the best format for citations in this kind of article. The worst part is that whoever supplied that paragraph failed to give page numbers and book titles. Leaving it the way it is would be better than deleting the citations. Somebody could look for the book that the original writer used, dig out some page numbers, and set up some footnotes. P0M 15:17, 30 January 2006 (UTC)

I'd really like to see more citations for the venom section. Numbers need sources. H2P (Yell at me for what I've done) 08:11, 29 July 2006 (UTC)

[edit] myth

Myth: When black widow spiders mate, the female always kills and eats the male.

http://www.washington.edu/burkemuseum/spidermyth/myths/blackwidow.html

[edit] Reverted claim

I removed the following claim (inserted today) from the article:

They (black widows) have the most potent venom of any spider in the world, but are less dangerous than Sydney Funnel Webs or Brazilian Wandering Spiders because those spiders produce a lot more venom. Black widows have venom 20 times as potent as the venom of the Common Cobra

Several things wrong: 1) The claim isn't substantiated by any reference provided by the author. 2) Making claims about which spider has the "most potent venom", without clarification of what is meant, are meaningless. It wouldn't surprise me to learn that that Latrodectus venom has a higher LD50 in mice than the venom of A. robustus or P. vera, but the latter spiders (especially the funnel-web) are known to be far deadlier to humans. And consideration of a venom's potency, without considering the typical dose, isn't very useful--were I to be deprived medical treatment and forced to choose between a full envenomation from a black widow or a Sydney funnel-web; I'd probably choose the widow, because I'd have a much better chance of surviving the experience. (Even though I'd likely wish I were dead for several days). 3) There is no such species as the the "Common Cobra". That sort of reference makes me suspect that someone is inserting an urban legend (probably unwittingly) into Wikipedia. (Latrodectus venom may well be more concentrated than cobra venom--which is deadly because of the quantity the snake injects--but it doesn't matter; one has a far better chance of surviving a black widow bite than a cobra bite; any species of cobra). --EngineerScotty 03:36, 7 March 2006 (UTC)

I didn't write the text that was removed, so I won't replace it, but widow venom is more potent, and less is injected. That is true. And you have simply one hundred percent agreed with what the text said. Why did you remove something that you agreed with? The information is useful- studies on venoms oftentimes require weak or stong potencies. As far as your "without clarification of what is meant", look up the word potency. And why does your user name have the word engineer in it if you are so obviously not an engineer? - till

I agree with the removal of the passage -- for several reasons.
The most important thing to bring to people's attention is that the venom of widow spiders is too little in volume to kill average-sized healthy adults, but not too little to kill people with less body mass to diffuse the venom through. So children should be taught to recognize this one species of spider and warned of its danger. These spiders just look like they mean business, so my impression is that children rarely seek contact with them.
The second thing to make clear to people is that the venomous funnel-web spiders of Australia has plenty of venom even for large adults, and they are not stingy about injecting into humans, nor will they run away the way the widow spiders will. But that information doesn't belong in this article
The LD-50 of the S. American wandering spiders appears to be very low. Fortunately these spiders seem to give mostly defensive bites. (I recently read that one of the main occasions for bites is a military training mission in which troops sleep in sleeping bags in the jungle. Getting in bed with a spider is not a good idea. Again, that information belongs in another article
There is supposed to be one other kind of spider that is even deadlier than the other three, but it is one that lives where humans rarely go, so the chances for actually being bitten are quite low. (I think they are a kind of wandering spider that digs burrows in sandy places.) We don't even have an article on that kind of spider yet.
Actually, we do; see six-eyed sand spider. --EngineerScotty 18:39, 26 March 2006 (UTC)
It must be a coincidence, but the chances of getting envenomated are inversely related to the toxicity of the venom. That means that even though widow spiders are not too likely to kill any given person, they account for the most deaths by spider venom the world over simply because their geographical range is so broad and there are so many of them per unit of land surface. The Australian venomous funnel web spiders used to kill people with some regularity, but since the invention of an anti-venom deaths have gone to zero or thereabouts. Again, comparisons don't really belong in this article.
What is interesting, and probably relevant here, is that it is very difficult to determine an LD-50 for spider venoms because they have vastly different effects on the various different kinds of lab animals that might be chosen for making tests. If memory serves, rabbits are almost immune to black widow venom, and horses are extremely vulnerable to it. So maybe you would choose lab rats -- but you still would not know how lab rat sensitivity compares to human sensitivity unless you injected measured doses of Latrodectus venom to both humans and rats. It might be theoretically possible to work out a ratio between human vulnerability and rodent vulnerability without killing too many humans in the process, but there would be strong ethical objections raised against performing skuch tests.
So, we have to deal with lots of approximations. We can measure the venom carried by large numbers of widow spiders and gain some kind of average among, but then we still would not know how much venom was injected in a given bite. The Australian critters aside, most spiders seem to bite as a way of telling people to stop squeezing them to death, and as soon as the human lets go the impulse to bite disappears. But I've never seen an opinion ventured as to whether widow spiders deliver a full dose or not. I think I remember reading one one dry bite.
That's probably one of the reasons that when I tried to collect information to use to characterize the degree of danger involved with various spiders I could not find even a single measure such as LD-50 or average venom volume for some species. Sometimes I found one measure, sometimes the other, rarely if ever did I find both. I think the lack of that information probably tells us something about how much the experts are concerned to be able to make these comparisons. Some of them are, however, interested in the medical use of the "active ingredients" of the venoms of spiders -- not all of them particularly troublesome to humans.
If I had to risk getting bitten by these spiders I'd be lots happier dealing with a black widow. I've had other members of their family run over my hand when I was trying to get them to hold still for a photograph, and it was a rather pleasant experience, actually. My next choice would be the South American wandering spider. I've noticed that they seem to be aware of the people who are photographing them, and they make a nice threat display. But if they are anything like my old tarantula they won't do anything unless you don't respect their threat display. I think I might even choose the super-deadly sand burrow dweller, whatever it is, over the Australian funnel-web spider -- even though I recently saw a picture of one of them resting on a spider fancier's bare shoulder. I get the impression from things I've read that the Australian ones tend to move toward humans who come withing their sphere of awareness. I would hope the other (sand dwelling) kind of spider would have the attitude that it wouldn't try to hurt me unless I tried to hurt it.
I'll go back, when I have a chance, and review the on-line articles I found. Someday we should have enough information to produce a real chart with volumes of venom, deaths per thousand bites, etc., which should be interesting. I seem to recall that there was one M.D. in Taiwan who was assembling such information. I think they have a member of the same family as the Australian terrors, and probably they aren't one of the few places to escape widow spiders. I doubt that they import very many crates of banannas from South America, but maybe they still have an interest in their wandering spiders anyway. P0M
I found some data, which I will add. I must go back through my "history" and recover the URLs. P0M 07:30, 22 March 2006 (UTC)
I've found some really strange data on LD-50 -- it looks like the right numbers with the decimal points misplaced. I am now working these materials into a separate article in which we can centralize all the "medical effects" information. As Scotty pointed out, various animals react in very different ways to the same venoms, and nobody is using humans for lab animals, so all of these figures are problematical. The most useful data will probably turn out to be "deaths per 1000 reported bites." The biggest surprise, so far, is the the Phoneutria are supposed to be the deadlies of all but the six-eyed crab spiders, but they don't actually kill very many people. It may be as other contributors have indicated--those spiders use only enough venom to discourage interference from humans, so most bites do not result in full envenomations. P0M 07:09, 1 April 2006 (UTC)
With some good help from my tarantula-loving friend from Finnland, I got some better information on the amounts of venom of the Brazilian Wandering Spiders. I thought the published figures (yes, M.D.s get things wrong too) were off by a factor of 100. It turns out that they were only off by a factor of 10 -- which means that each of these spiders have enough venom to kill a roomfull of people. I have to track down the reference again, but I recently saw something that indicated that many of the bites by those spiders occur when soldiers are camping in the jungle as part of their exercises. A spider and a human being get into the same sleeping bag, and then somebody gets hurt. Fortunately they rarely die. The spiders exercise restraint. I corresponded with a lady here in North Carolina who wrote that she was putting on a shoe in which a large wolf spider had taken refuge and its bite pierced her toenail. She said she didn't "get bitten," by which I guess she must have meant that the spider let go as soon as she pulled her foot out of contact with it.
The data I have accumulated is still rather shaky. Different people measure things in different ways perhaps. Anyway, the main trouble with the data is that research is usually done on lab mice and the spiders frequently have very different kinds of venom, so something that didn't bother a mouse at all might bother a human being a great deal, or vice-versa. Some other lab abnimals seem to have very different kinds of responses form those of humans, so I guess the mouse data are the best we can get unless people get busy and compile data on the number of deaths or other serious consequences per 1000 reported bites.
For what its worth, the comparisons are at Spiders_having_medically_significant_venom. I need to tidy them up some now that final exams are past. P0M 04:18, 17 May 2006 (UTC)

[edit] L. hesperus and L. variolus, again

This subject was discussed above, a while ago, but without much resolution:

Does the term "black widow", absent any regional qualifier like "western" or "northern", refer only to L. mactans, or does it also refer to L. hesperus and L. variolus, the other two species commonly referred to as "black widow" in North America? From what I can tell by looking at the literature, it can be argued both ways; I've seen examples of papers and other authorative sources referring to L. hesperus as the "black widow", without the "western" prefix. (Especially here in Oregon, where L. mactans and L. variolus are not found).

The general public (in US), for the most part, is unaware of the difference(s) between the species; and in order to really tell them apart reliably you have to get them under the microscope. Wikipedia generally uses common names for things, which suggests that L. hesperus and L. variolus ought to be more fully described in this article. As the species have more in common than in distinction, this makes more sense than writing separate articles for the northern and western widows.

I wouldn't extend this treatment to other widow spiders like Latrodectus tredecimguttatus, which are occasionally referred to as "black widows" in English but are called something else (Karakurt, etc) in the languages natively spoken in their range.

--EngineerScotty 20:16, 1 June 2006 (UTC)

I'm not sure of the history of species differentiation/identification. Kaston's edition of 1953 does not mention any U.S. species other than mactans, and the descriptions he gives make it seem to me that he and his colleagues at that time were identifying all U.S. widow spiders as L. mactans. If that is the case, "black widow" would have surely applied to all of them then, and it seems unlikely that anybody has come up with a rationale for claiming we can only call L. mactans a "black widow." The important thing is for people to be able to identify the spiders that they really need to teach their kids not to mess with. So I think you are right to keep together the ones that would be regarded as "the same" under casual inspection. P0M 00:50, 4 June 2006 (UTC)

[edit] Killing their mates

Black widows do not kill their mates as part of mating ritual. (The redback spider, a cousin of the black widow from Australia, does kill its mate--the male actually jumps into the female's mouth--but this article is about the North American species).

The reason for this belief is that black widows in captivity frequently would. Black widows, like many spiders, will happily eat other spiders that they can capture; and in captive situations (where the male has nowhere to go), the female would often capture and eat the male after mating. But observations of mating in the wild have revealed that male widows usually escape after mating.

For that reason, I reverted the recent suggestion that widows do regularly eat their mates. It is simply not true. --EngineerScotty 19:52, 15 September 2006 (UTC)

[edit] Size in Description is incorrect

The Description says

A large female black widow spider can grow to 5.0 inches (51 mm), counting legspan. The body is about 1.75 inches (20 mm).

The mm dimensions are not equivalent to the inches measurements. An inch is 25.4 mm exactly. I'm not sure which of the measurements (inches or mm) is correct, however. Is there an entomologist in the house?

KerryVeenstra 00:34, 29 November 2006 (UTC)

Not only is the conversion wrong, somebody has been messing with the basic description. A black widow spider with a legspan of 5 inches would be huge. The legspan measurements are not very precise. Judging by some of the spiders I have bought by size the dealers must have an eight-peg device that they tie the spider's legs to and then they stretch the spider out to the max. Usually it is hard to get any spider to "stretch out" for you, and black widows do not stretch out at all unless they are running up or down their web in the process of subduing a large moth or something of that size. The body is not 1.75 inches either. That's bigger than the largest wolf spider in the United States.
Thanks for alerting us to this faulty information. P0M 03:47, 1 December 2006 (UTC)

[edit] Removed unsourced assertion.

An anonymous user added: "The lethal dose of the black widow venom is reported as an LD50 of 0.0009 mg venom / gram body weight (mouse)." If a valid source can be found for this information, the information and citation should be added to the Spider bite article. P0M 16:11, 24 December 2006 (UTC)

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