Loxosceles ( brown recluse spiders )

[Laurens]

after a few posts I thought it might be good to tell you something about my favorite spider species.
As in my last post someone had a question about the reason for keeping a specific spider.
Let me be the first to start with this subject
If there's one spider to be interested in, brown recluse spiders could be that species to enjoy investigation.
The behaviour of recluse spiders is very interesting to watch as in hunting strategy's, night activity and communion behavior.
I beleave the toxicity of this spider is just coincidence when it comes to the sphingomyelinase D and its effect on the human body.
with this in mind I do not think of this spider as a serious threat as recluse spiders are ''reclusive'' like their names and only bite as last choice.
The damage caused by an accidental bite could go from minor ( blister.swelling like ) to medically urgent ( lesions/tissue damage ) possibly spreading.
best way to avoid being bitten, this offcourse counts for all venomous animals. for some its just a scary little spider, but for me its like a world to discover.
Im always trying to answere as much of the questions but for now I leave you guys with the 2 subspecies Im breeding with.

Loxosceles laeta ( Chilean recluse spider ) Adults








Loxosceles rufescens ( Mediterranean recluse spider ) juveniles

 

[pannaking22]

Very cool! They are a very interesting genus.

 

[Laurens]

they truly are pannaking22 its not just an ordinary spider to be afraid of

 

[Richard McJimsey]

I'd love to get some laeta. Currently growing up some reclusa and rufescens.

 

[Laurens]

Great species Rick, I would love to have reclusa but I haven't found them yet.
they are on my wanted list like L.intermedia and L.deserta

 

[pannaking22]

After reading through Rick Vetter's book, I wouldn't mind getting some African species as well.

 

[antinous]

Wouldn't mind getting a few of my own either, when I get my own place. I'd love to collect all the species and see how their behavior ranges, as well as with the rest of the Sicariidae family.


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[Venom]

Just a reminder...but the L. laeta, L. intermedia, L. gaucho population in Santiago, Chile, causes regular fatalities. According to a study submitted to the National Institutes of Health, the collective fatality rate of these three species (mostly due to L. laeta) is 3.7% (1 death per 27 cases...which is not a funny stat), and serious blood and kidney poisoning occurs in 15.7% of bites (1 in every 6 cases of envenomation). Source: http://www.ncbi.nlm.nih.gov/pubmed/2577020

Those are some sobering stats! Why such high numbers of serious envenomation? Because the venom of L. laeta contains an ORDER OF MAGNITUDE (meaning 10 times!) more sphingomyelinas-D than does L. reclusa. "It is striking that venoms of L. laeta and Sicarius yielded an order of magnitude more total venom protein upon electrostimulation than the other Loxosceles species surveyed" - Source: http://www.lclark.edu/~binford/SMDDistribution copy.pdf

L. laeta should not be treated like L. reclusa, which generally has only mild to moderate local results and very rarely systemic symptoms. L. laeta has a HIGH prevalence of systemic poisoning, with a rate of fatality almost on par with Tityus serrulatus, and a rate of local poisoning of above 84%. Conclusion? Loxosceles laeta should be treated with as much caution as Sicarius spp.

 

[antinous]

^That's pretty interesting! I was wanting to find out if one species is 'more' venomous than the other, guess this makes it easier haha. I know there's a species of snake (possibly cobra? forgot, was a while ago) that occurs in Sri Lanka and India. One was more toxic than the other, but I forgot which one was. Anyways, it's always interesting to see if one subspecies is more potent than the other.

I'd still treat every venomous animal with the same respect, be it deadly or not, but that's just me.

 

[Venom]

^That's pretty interesting! I was wanting to find out if one species is 'more' venomous than the other, guess this makes it easier haha. I know there's a species of snake (possibly cobra? forgot, was a while ago) that occurs in Sri Lanka and India. One was more toxic than the other, but I forgot which one was. Anyways, it's always interesting to see if one subspecies is more potent than the other.

I'd still treat every venomous animal with the same respect, be it deadly or not, but that's just me.

I'm glad you enjoyed the info! Just FYI, L. laeta isn't a subspecies of L. reclusa though, but a full species on its own. There are over 50 species of Loxosceles "brown spiders" / "recluse spiders," and there is a great range of toxicity in the genus, from nearly-benign species like L. deserta to very seriously venomous species like L. laeta and the other Chileans.

 

[antinous]

I'm glad you enjoyed the info! Just FYI, L. laeta isn't a subspecies of L. reclusa though, but a full species on its own. There are over 50 species of Loxosceles "brown spiders" / "recluse spiders," and there is a great range of toxicity in the genus, from nearly-benign species like L. deserta to very seriously venomous species like L. laeta and the other Chileans.

Thanks for catching my mistake haha. I only just started reading some papers on them to learn more, and even tho I read they're different species, it's still engrained in my head they're subspecies for some reason aha.

That does remind me, while in Peru, a professor had brought back a Loxosceles sp. At that time I wasn't too into true spiders, as I am now, so I just wrote it off as L. reclusa, which was obviously wrong. Looking back, I wish I was able to take photos of it to see which species it was aha.

 

[pannaking22]

Thanks for catching my mistake haha. I only just started reading some papers on them to learn more, and even tho I read they're different species, it's still engrained in my head they're subspecies for some reason aha.

That does remind me, while in Peru, a professor had brought back a Loxosceles sp. At that time I wasn't too into true spiders, as I am now, so I just wrote it off as L. reclusa, which was obviously wrong. Looking back, I wish I was able to take photos of it to see which species it was aha.

Photos might not have helped you too much since there's so much similarity between Loxo sp. and coloration isn't as helpful because they can change color to an extent depending on what they last ate (from Rick Vetter's recluse book). Identification will likely come down to checking out the genitals because that's how arthropod taxonomy works anymore lol.

Great post as always, Venom, and a good reminder to people that (potentially) highly venomous spiders aren't something to be messed with.

 

[antinous]

Photos might not have helped you too much since there's so much similarity between Loxo sp. and coloration isn't as helpful because they can change color to an extent depending on what they last ate (from Rick Vetter's recluse book). Identification will likely come down to checking out the genitals because that's how arthropod taxonomy works anymore lol.

Great post as always, Venom, and a good reminder to people that (potentially) highly venomous spiders aren't something to be messed with.

Ah, thanks for the heads up. And now I really want his book haha.

Most be hard to keep the different species then since they do look similar then.

 

[Hanska]

A question just popped in my head. Can Loxosceles spp. climb glass/smooth plastic?

 

[The Snark]

^That's pretty interesting! I was wanting to find out if one species is 'more' venomous than the other, guess this makes it easier haha. I know there's a species of snake (possibly cobra? forgot, was a while ago) that occurs in Sri Lanka and India. One was more toxic than the other, but I forgot which one was. Anyways, it's always interesting to see if one subspecies is more potent than the other.

I'd still treat every venomous animal with the same respect, be it deadly or not, but that's just me.

Probably Russells viper. The colder the clime, the more hemotoxin is present in the venom which aids in prey digestion. Unlikely to be similar to spider venom variations between species, but something to consider.

 

[pannaking22]

A question just popped in my head. Can Loxosceles spp. climb glass/smooth plastic?

Not very well from what I've seen. If there are little scratches they can sometimes get footholds, but they aren't great at climbing smooth surfaces.

 

[Hanska]

Not very well from what I've seen. If there are little scratches they can sometimes get footholds, but they aren't great at climbing smooth surfaces.

Ok, thanks. I've been thinking about L.laeta but this thread has put some new insight on the subject. I guess the ms. has a good point to deny me one. Not that the Latros or the Sicarius puts her off put Loxos she finds ugly. And I think "It's not that bad" no longer cuts it.
And thanks for the paper Venom. I had no idea L.laeta was that much of the scale.

 

[Laurens]

its been a while, sorry busy busy days
About Loxosceles venom, there are a lot in researchers who tried to find out the differences between the venom of all the species of recluse spiders.
Due the fact that the Chilean recluse spider is the largest species of recluse spider it pretty obvious that they contain a larger amout of venom, not nessacarely more toxic.
Yes I´d beleave there are some variations but in context with the damage it can cause, in my personal oppinion its the amount of venom what differentiate the dangerousness.
All species of Loxosceles have a very tiny amount of venom in their glands and most subspecies don´t even grow big enough to posess a real danger to a human being.
about the climbing, recluse spiders usually don´t climb on smooth surfaces this goes for adult specimens. but they still can climb on every little scratch or between small surfaces
including glass when there´s less room between it so it can press itself up or using a tiny bit of their web on their legs.
The documents above are really interesting offcourse, and I´m familiar with the work of Grady binford so its really reliable information.

at the end I need to show you guys something that made me really happy yesterday !!

 

[pannaking22]

Nice, congrats on the sac! Which species is that?

 

[Laurens]

thanks, Loxosceles laeta