Talk:Latrodectus mactans

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Economic Use[edit]

An interesting fact: Silk from widow spiders is harvested and used for making reticles for fine optics and the like. JE1977 01:11, 21 July 2007 (UTC) (talk) 04:36, 18 April 2008 (UTC)

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: 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

How long do the males live?[edit]

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)

A species made in the bowels of Hell[edit]

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.)

Uh, could we add a section on their adolescent stage I saw one these but smaller only I am not certain as to if it really was one or not. how can you tell if it is one. it is black with red on it but has a much smaller abdomen and I swear I see an hour glass, scary stuff.-- (talk) 16:01, 21 October 2008 (UTC)

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)

Widow's Web[edit]

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?

Enough citations?[edit]

"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)


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

Reverted claim[edit]

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)
I found and removed this claim again for the reasons given above. Sperril 15:53, 13 May 2007 (UTC)

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

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)

Killing their mates[edit]

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)

Size in Description is incorrect[edit]

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)

Removed unsourced assertion.[edit]

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)

A few comments mostly about the difference in species[edit]

I don't have enough expertise to edit this article but I felt that some of the information is not consistent with what I understand the case to be.

From the article: "Adult female black widow spiders are gloss black with an hourglass shaped marking on the topside of its abdomen..." I believe the hour glass is on the bottom side of the spider for the western black widow. I live in CA and I don't recall ever seeing any black widow spiders with red markings of any kind on the top of the abdomen.


The book "The book of Spiders and Scorpions" (1991) by Preston-Mafham has drawings of the Northern and Southern species which show red dots on the top of the abdomen of the Northern species and an hour glass on the bottom of the Southern species. The book suggests that the western and southern black widow females are similar in appearance but that the males appear significantly different. Both males are about half the size of the females but the western male is a light brown color with strips and the southern male appears similar to the female except for its size.

Which brings me to a general complaint about the article. There aren't any pictures or drawings of the males.

If you can find such pictures, please provide them. P0M 02:17, 31 May 2007 (UTC)

I just linked to a picture of a western black widow male (I took it, I believe it might be a second instar). I wasn't sure where in the article to put it. Right now the article does a poor job of providing information about how to differentiate the three species. The males seem to have the most visible variations between the three species and pictures of them probably should be included in a section on differentiating the three species. The females also have visible variations between them and at least some pictures indicating those differences would be nice. Right now the pictures selected for this article are not great. I was looking through wikicommons in latrodectus category and saw a few that might be superior (for the purposes of this article) to the ones linked to in this article. Davefoc (talk) 17:51, 7 September 2008 (UTC)

Concerning egg incubation period[edit]

I have within the last 6 months caught several black widow spiders around the premises of my house and was surprised to see that they could produce eggs without a male. Later, I learned the reasons behind this, but I am writing to acknowledge an apparent discrepency in information. The information in wikipedia states that the incubation period lasts "twenty to thirty days," which I have found to be grossly wrong. I planned on twenty to thirty days, and was surprised when by the end of this time, the only thing I found was another egg sac. I concluded that these eggs were in fact not fertile and disregarded them for several months. At the end of the third month I was surprised to find hundreds of tiny black widow spiders crawling in the jar, only from one of the eggs (I assume the first). In all three of the spiders I caught the timing on the eggs was nearly the exact same - egg laid within ten days of being caught and hatching about 3 months later. I changed the info the day of the hatching and came back to see it has been edited back, so here is why I changed it, and have done so again. --Pariah316 02:26, 28 May 2007 (UTC)

As you have probably read, the females of some cold-blooded animals can keep sperm viable within special receptacles in their bodies for a long time.
Fertilized eggs can stay dormant for some time. In plants, a seed may lie dormant for hundreds of years. (I think the record was for some seeds found in Egypt a few decades ago.) Birds lay fertile eggs but do not start to brood until they have finished laying; that way the eggs all hatch at the same time.
So it would not be surprising to find that spider eggs can hatch after different time intervals. At one time there was a great interest in black widow silk for making reticles in gun sights, so people probably made many observations at that time because they would have been breeding the black widows in preference to having to go out to catch them in the wild. They were probably interested in getting the eggs to hatch promptly by providing optimal temperature, humidity, etc., so their eggs may have hatched much faster than the ones you observed.
We are not allowed to include personal research in Wikipedia articles, so what you will need to do is to track down some scientific research that can be shown to be objective. P0M 02:33, 31 May 2007 (UTC)

Are they large or arent't they?[edit]

Opening paragraph describes "large widow spiders," then in the section about venom, it says they "aren't especially large."

They aren't the size of your hand or anything, but they are big enough to notice a huge spider crawling around. The body is about the size of your thumb, and then add some nice long legs to that, and you have your lovely black widow. —Preceding unsigned comment added by (talk) 09:10, 22 October 2008 (UTC)

Creationist myth smuggled in???[edit]

"Males, being less venomous, are less of a threat to predators, so having similar marks not as prominent helps predators to better judge their prey (some large birds can eat male widows without adverse effect, and so only avoid female spiders."

The above passage, found in the article, implies that make black widow spiders have less-prominent markings because it helps certain predators realize that they are safe to eat. Stated without qualification, a creationist could use this article to form the argument from ignorance that a deity must have created male black widows to serve the purpose of food for certain animals, because (the creationist would posit that) natural selection would never result in this situation.

The creationist tone of this passage could be corrected by invoking the handicap principle, which states that certain species have disadvantageous traits due to sexual selection. It would then still be true that male widows have less-prominent markings because it makes them vulnerable to predators, but it would no longer sound like this was to the sole benefit of the predators-- female black widows prefer to mate with males that have avoided predation in spite of their less-prominent markings. 21:05, 4 July 2007 (UTC)

Taking a single badly-worded sentence and turning it into a conspiracy theory propagated by those insidious, sinister Creationists seems to me like just a little bit of a stretch, don't you think? As far as I'm concerned, feel free to change the sentence if you can come up with a clearer version that doesn't drag a bunch of irrelevant information into the article - but if (as I suspect) what you're really looking for is someone to argue with, then I don't think that will satisfy you. 'Card 18:43, 5 July 2007 (U


Black Windows are found in Arizona alot.. but only in some areas. you do not see them alot anyway they are usally hidding too. And they do not bite you unless you try to kill it or take down its web. In Arizona i do not see how that bug can survive as it is today it is 115 deggres. even if we do have alot of bugs i do not see them. I have lived in Arizona for about 3 years and have have not seen 1 single black widow. before that i lived in Florida and that had black widows too. I did not see a single one there ethier. I lived in Florida for about 3 1/2 years.The reason why we do not see them is because they are busy doing other things like making a web, taking care of there egg sack, ect. and they do not have time to bite us or scare us they have way more important things to do. Bugs will not hurt you if you do not hurt them. If you have one in your house be nice and let it crawl into a jar and let it go. that way you did not hurt the bug and the bug will not hurt you. Not many people are a big fan of bugs but just know they are like people but really tiny and have venom in them.

Arizona - Rob

Hi - I also live in AZ (Phoenix) and am constantly killing black widows, mostly in the yard (but also in the garage) I'm taking note of the nesting locations, then a night I arm myself with a flashlight, poison spray, and a weapon (broom etc). This summerI've killed at least 15 females - 4 per night on 2 different nights! Can anyone post pics of the males as well (it does take 2 to tango, afterall!)I'd like to rid my yard of them as well. I also lived in Fla, but only saw a few widows there. But North Florida's loaded with brown recluses. Not here in Arizona, yet.....


On two occasions I've spotted a spider much similar to the black widow, only I'm certain that the hourglass was on it's back. I've looked into the possibility of it being an Australian Red-Back however the red formations on it's back looks nothing alike, and I live in Israel, which is, well, fairly far from Australia. One was spotted indoors, the other was building a web between a wall and the street floor-which is unusual for a black widow. (BTW by back I mean the top of the abdomen) —Preceding unsigned comment added by (talk) 19:50, 30 October 2007 (UTC)

Any clue as to what it is? —Preceding unsigned comment added by (talk) 19:46, 30 October 2007 (UTC)

On Widows the hourglass is on the stomach not the back. Usually it's red for females and orangish for males (whom are smaller and less poisonous). —Preceding unsigned comment added by (talk) 06:04, 15 August 2009 (UTC)

Immature spiders look different[edit]

The immature spiders of Latrodectus mactans especially look rather different, such that people unfamiliar with them might easily misclassify them as some other species. It might be a good idea to add a section about their development, potentially with pictures like in (which seems to be cc-non-commercial?) 08:10, 5 November 2007 (UTC)

Living Locations[edit]

A section on where these are commonly found would be nice. Speaking as a meter reader, the most common place in the southeast to see Black Widows are inside water meter boxes and around gas/electric meters attached to houses. Fyi, I see a couple dozen of them a month. Anyone wishing to make sure their property is widow-free should start with their meter box. It might also be useful to know that reaching near one of their webs will get you bitten, it's happened to me.

Noted, I saw a large female black widow here in Las Vegas which points to them being native/spreading to this area. I have adjusted the local extension from Arizona to Nevada, though they're likely spread throughout the southwest. Usually they are fairly reclusive but this one was building a web from the sidewalk to a shrub (remarkably). Comparable to the size of the widows I used to see in Pennsylvania, around an inch from hind leg to head.

Contradiction in Description of Males[edit]

The first paragraph of the description contradicts itself. It says "And male black widow spiders' hourglass color is yellow to white to various shades of orange and red.", but it also says that "They are also usually dark brown with varying colors of stripes/dots, with no hourglass mark." Do the males have hourglass markings or not?

Also, it'd be good to have a picture of a male. —Preceding unsigned comment added by (talk) 07:08, 22 January 2008 (UTC)

Male Widows absolutely have the same hourglass markings on their bellies. Usually they are smaller (half the size) and their markings are in Orange. I have only seen females with Red markings. Neither are aggressive and generally the females only bite when threatened and/or protecting an egg sack. —Preceding unsigned comment added by (talk) 06:07, 15 August 2009 (UTC)

I located a decent picture of what the male will generally look like here:**http%3A// . Not sure if fair use applies. —Preceding unsigned comment added by (talk) 06:14, 15 August 2009 (UTC)

Caveat: I'm not an expert and I might be wrong. I suspect the spider you posted a picture of is a brown widow female. The Latrodectus hesperus article has some pictures of males (which I took). I suspect the L. mactans males look similar. They do have an hour glass or sorts but they look yellow to my eyes.Davefoc (talk) 09:14, 15 August 2009 (UTC)

Contradiction in Reproduction Section[edit]

On the page, it does have contradictory information under the "reproduction" section, saying, "Contrary to popular belief, the female only rarely eats the male after mating..." and then stating, "This is a general misconception, as the name seems to suggest that the males are invariably consumed after mating." Just pointing this out. —Preceding unsigned comment added by (talk) 21:45, 11 August 2008 (UTC)

Those sentences aren't particularly well written, and are easy to misunderstand - but if you read them carefully, they're actually saying the same thing. They're somewhat redundant, but not contradictory. - Ken Thomas (talk) 22:10, 11 August 2008 (UTC)

SVG picture of Black Widow - Si tu veux[edit]

I vectorised a black widow, take it or leave it.

[Black Widow SVG]


It's a great illustration, but I'm not sure we need it on this article when there are so many excellent, high-resolution photos of actual Black Widows available. My suggestion? Upload it to Commons instead, and add it to the Latrodectus category. That way people who follow the Commons link from the article will see it there. - Ken Thomas (talk) 14:02, 1 September 2008 (UTC)

Administrator question: what's wrong with my ref (format)?[edit]

Why does the ref generated by:


...just show the .pdf filename as hyperlinked (or why does it show it AT ALL), when:


...seems to work just fine?


Thanks, philiptdotcom (talk) 20:05, 7 November 2008 (UTC)


Intro is TOO LONG[edit]

There's too much info before the "Contents" box. Most of the info (past the first paragraph, e.g.) should be moved under a topic heading. philiptdotcom (talk) 20:09, 7 November 2008 (UTC)

Red Hourglass Marking on underside of Abdomen?[edit]

How in the world can the entire Black Widow article avoid talking about the appearance of the spider in question? Not including this kind of info makes the article ridiculous, and especially unhelpful. (talk) 18:30, 17 December 2008 (UTC)Derek

The hourglass marking is extremely variable. From almost nonexistant to completely full. Though, I dont see how adding info about the feature would better the article any...It *might* have a place on individual species articles, but not really on this page.(Also, there is already a bit about it on the genus page...) Arachnowhat (talk) 18:42, 17 December 2008 (UTC)

Male widows, and a question on the name in general[edit]

Are the males formally called "black widowers", or do they not have a gender-specific name? It seems odd that male spiders would have a female name. Also, historically, were the spiders originally called "black widows" simply because their black colour resembled a widow's dress, or was their supposed sexual cannibalism a widely-known trait? -Ashley Pomeroy (talk) 20:33, 22 December 2008 (UTC)

As far as I know the male black widow spiders, are referred to just as "male black widows" or "male black widow spiders". As for the name, I dont know for certain, but I would expect that it was related to the belief that was very common in the past involving the males almost always being eaten and not due to the coloration(something that is quite variable). - Arachnowhat (talk) 23:23, 23 December 2008 (UTC)

puzzled about this spider[edit]

I don't have the best eye sight, and am spider phoebic (though I try to make myself face it) but what I first was certain was a black widow I found a few minutes ago, I'm not so certain of, in retrospect. it was black, hung upside down, showing a redish mark on it's belly, but it wasn't bulbous at all. most of it's length was in it's legs. the body was more in the shape of the yellow and black garden spider, with the long legs that splay outwards rather than curl in like a black widow's can. I've looked at the "false black widow", and I've never mistaken them for a black widow, though we have plenty of both where I live. this wasn't one of them. also, it had chosen a high profile area, not a standard of the black widow. it's too late to go back and check it, I vacuumed it up and tossed the vacuum contents. was it a black widow? if so, why was it in a light web over the little used chair in a well lit corner (we live in spider capitol, U.S.A., nothing keeps them out of the house) instead of a powerful web in a dark area? we did have a true black spider make a nest near the door last summer, and it, also, wasn't in a very dark area, but it was behind a picture I'd propped up to take out to the car. —Preceding unsigned comment added by (talk) 23:52, 16 January 2009 (UTC)

Black Widow Spiders found only on the Bruce Peninsula in Ontario?[edit]

With all due respect to John Acorn's abilities as a naturalist, if he is being quoted correctly in the current version of the article, I'm afraid even a cursory amount of research indicates that he is incorrect in claiming that the Bruce Peninsula is the only location in Ontario where Black Widow Spiders reside:

The journal article below (on page 40) indicates that specimens of Black Widow Spiders have been obtained on the Bruce Peninsula in the past, but they have also been observed in both Lambton and Norfolk Counties, both of which are located 100-150 kilometers south of that location:

The Spider Genus Latrodectus (Araneae, Theridiidae) Herbert W. Levi; Transactions of the American Microscopical Society, Vol. 78, No. 1 (Jan., 1959), pp. 7-43.

Northern Black Widow Spider (Latrodectus variolus) documented in the 1990's in the Pinery Provincial Park, 100 kilometers south of the Bruce Peninsula: [1]

Photograph of Northern Black Widow Spider "in the wild" taken near Minden Ontario 2002, 200 kilometers east of the Bruce Peninsula: [2]

Black Widow Spider documented by Ojibway Nature Centre in 1995 near Windsor Ontario, 200 kilometers south of the Bruce Peninsula: [3]

Iowa State University Entomology Department site stipulates range as "south-eastern Canada", it does not restrict the spider's range in Canada exclusively to the Bruce Peninsula in Ontario:[4]

Medical and Veterinary Entomology By Lance A. Durden also describes range as "south-eastern Canada": [5]

Based on this information, I will be revising the present article. cheers Deconstructhis (talk) 20:42, 19 January 2009 (UTC)

Other countries[edit]

I live in South Africa and black widdows are common. This article makes it seem like a black widow only occurs and has its origin in the US. In Afrikaans it is called a 'Knoopie Spinnekop'. Directly translated into 'Button spider'.

-- (talk) 08:09, 18 February 2009 (UTC)

Very true, it does seem very Americas-centric in its wording. Did South Africa always have widows or are they an unintentionally introduced species. The article needs to include all places they are found for sure, the range section I just combined from the other disparate parts could be broken up into continents and native/introduced sections. Mfield (talk) 08:21, 18 February 2009 (UTC)

And also in Romania in Dobrogea —Preceding unsigned comment added by (talk) 10:35, 7 June 2010 (UTC)

In response to all of your comments, Latrodectus mactans only occurs in the United States and Mexico naturally. It has been introduced to a few other countries in small populations but, in almost all cases, the spiders you are talking about are different species of Latrodectus. Subverted (talkcontribs) 05:16, 10 June 2010 (UTC)

Focusing this article on L. mactans[edit]

I didn't see any discussion of the change. It looks like Cygnis insignis just thought it was a good idea and did it. And maybe it was the right thing to do.

But the article now starts off in a very misleading way. Black widow is a common name obviously and the scope of that word undoubtedly varies from individual to individual and location to location, but I suspect that the vast majority of people who use the term (at least in the US) are referring to the species (mactans, hesperus or variolus) which is near where they live. Who says that a black widow spider is only L. mactans? Is there an official determination that only L. mactans are black widows? This is absolutely inconsistent with common usage.

Based on my understanding (and I stand to be corrected) this article should be called Southern Black Widow or preferably Latrodectus mactans.

One thing that has been consistently missing from this article whatever it is called is how are the three species differentiated. It does appear that some patterns are unigue to a particular species but it also seems like the spider can exist in forms where all three species are visually very similar. Probably the scientific basis for distinguishing between the three species is based on an examiniation of the sex organs. If this is the case the article probably should mention that fact.

I wondered, given how similar the three species are, whether they could interbreed. I came across a study which looked at that issue and the results of the study suggested that they could not interbreed and produce offspring as I recall. I linked to that study in the Latrodectus article. But it might be useful to reference the results of that study in the article.Davefoc (talk) 06:18, 10 March 2009 (UTC)

There is not much I can add to that, I made some edits to many the members of the genus. This article was constrained by being wedded to a common name, the subsequent edits have helped to unravel this web. I moved it to the accepted name from the most reliable sources. I'm sure that splitting the other species to their respective names will facilitate their improvement. I also changed the dab at Black Widow. cygnis insignis 09:13, 10 March 2009 (UTC)
Agreed, the article previously had an even more unlikely claim, that the southern black widow specifically was the most well known of the widow spiders. Given the range of the western black widow over the highly populated areas of the west coast, and the fact that the public in general would refer to any black spider with a red hourglass, i.e. any of the three species, a black widow, i rephrased it. It now keeps the three species as a unit when talking about public perception, which seems less uncertain of a claim. Mfield (talk) 16:31, 10 March 2009 (UTC)

Reproduction Guidelines[edit]

I think that more information is needed in the reproduction section of this article. These questions should be all answered by the time a reader is done reading the reproduction section.

  • Is this animal gonochoristic (separate sexes) or hermaphroditic?
  • What kind of mating system does this animal exhibit? Provide a brief description of its mating system.
  • How often does mating occur? Do individuals mate only once in their lifetimes? More than once? If more than once, at what time intervals does mating occur? Of what age does one of this animals typically have to be to mate (about how long does it take, after being born or hatched, for the animal to reach adulthood)? Does that age differ between males and females?
  • When does mating occur? Only during one time of year, during a restricted “breeding season”? Or can mating occur at any time once an animal reaches adulthood?
  • How often are males “ready” to mate? Do individual males typically mate with more than one female? Is there variation among males in how many females they mate with?
  • How often are females “ready” to mate? Do individual females typically mate with more than one male? Is there variation among females in how many males they mate with?
  • How do members of the two sexes get together? How do they find one another?
  • Is there courtship of one sex by the other? Which sex performs courtship behavior? What does courtship behavior entail?
  • Is there mate choice exercised by one sex? Which sex does the choosing? What is known about criteria on which mate choice is based?
  • Do the members of one sex fight or otherwise compete with each other for access to, or control of, mates of the opposite sex?
  • How are sperm and egg (ovum) brought together for fertilization? Is fertilization internal or external? If internal, do males have a penis or some other intromittent organ? Do females have a penis or some other intromittent organ? Does this animal species employ spermatophores or sperm packets for fertilization? If fertilization is external, how does the animal maximize the chances of fertilization?
  • In this animal species, is rape or homosexual behavior known to occur? (talk) 15:01, 11 March 2009 (UTC)

Range of the spider[edit]

I am no expert in the subject of spiders however I am a native of Cuba. In the intro and then in the Range section the article says the species appears in the southeastern US and Mexico. However, I believe that the range of the species is much bigger (pantropical) and it certainly includes caribbean islands such as Cuba. The introduction of the spanish version of this article suggests that the spider is to be found all the way from Mexico to Chile. In the case of Cuba, I don't know if they are introduced but I doubt it since many species found in Florida are also found in Cuba and also taking into account that there are documented experiments on black widows in Cuba going back at least to the 30s [6](in spanish). As for the actual presence of it, there doesn't seem to be much need of documenting it since there is already a picture of Latrodectus mactans taken in Cuba near Havana in the wikimedia common files which are linked by this article [7] Airsh (talk) 07:21, 6 November 2009 (UTC)


It is known that a colateral effect of the bite of this spiders is priapism. Spanish wiki asserts that. —Preceding unsigned comment added by (talk) 16:08, 17 March 2011 (UTC)

Proposed move at Black Widow.[edit]

For any editors concerned, there is a proposed moved at the disambiguation page Black Widow. If you have anything to add to the discussion, please do. Weebro55 (talk) 03:52, 26 June 2012 (UTC)


This article states: "The southern widow is primarily found in (and is indigenous to) the southeastern United States, ranging from Florida to New York..." New York is now in the southeastern U.S.? — Preceding unsigned comment added by (talk) 18:42, 5 August 2013 (UTC)

Problems with the current reproduction section.[edit]

The section on reproduction states that "It takes two to four months for black widow spiders to mature enough to breed". It then also states that the lifespan of a male is about three days. Is that not impossible? How could the species ever reproduce within those parameters? Furthermore, the sole reference in the section does not corroborate this. The cited page states " Males mature about 70 days after emergence and live only another month or two." There appears to be no source for the listing of three days and it doesn't make any sense in relationship to the other details about this species life cycle so I assume it has to be incorrect.

Furthermore, the one citation gives information that conflicts with the article section's stated life span of females, number of eggs laid, and number of young that survive. Almost none of the section's details match its only reference. The veracity of the reference itself, mind you, is not something I'm entirely confident in (the full descriptions do not always match the stat summary).

It generally seems as though the section needs an overhaul.


~Evander Berry Wall. — Preceding unsigned comment added by (talk) 06:28, 19 June 2015 (UTC)


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