Latrodectus sp from San Antonio

Canth

Arachnolord
Old Timer
Joined
Dec 16, 2005
Messages
655
I posted these in the Arachnocon Picture thread already but I'm interested in getting these IDed so I figured I'd just post them here.

Pretty L. hesperus which I believe to be adult.


And a teeny L. hesperus male. I need tips on breeding these so, the more the merrier. I'm thinking of waiting a week or two to see if any of the wild ones produce sacs and if they don't, I'll introduce him to them before my two virgin females.


I'm pretty sure this one might be L. mactans. Also adult


And that concludes my IDing ability. These 2 are ones I'm not sure about but am leaning towards hesperus.

Adult



Juvie


After looking at all the pics and spiders, I think they're all hesperus. They all have a white bar or dot right above the cephalathorax like in the juvie above.
 

Python

Arachnolord
Old Timer
Joined
Mar 21, 2005
Messages
631
I'm not sure but the red spot just behind the spinnerettes seems to say mactans to me. Also if I'm not mistaken, in hesperus, the hourglass is seperated in the middle while in mactans it isn't. I could be wrong. I've had several adult female mactans with white on the abdomen just above the carapace and I've had them with red there too. They are beauties but I think the first one is still a juvie. I'm not sure on the range of the Lats but I'm pretty sure those are mactans.
 

Canth

Arachnolord
Old Timer
Joined
Dec 16, 2005
Messages
655
If that first one is a juvie, she'll be a huge Latro. I'm almost positive she's an adult. Is it possible that the mactans and hesperus intergrated?
 

buthus

Arachnoprince
Old Timer
Joined
Jun 8, 2006
Messages
1,381
1st hesp ...like I said before on VL, if she is an adult, she is special. I have a feeling she will molt again though. (hope Im wrong ...;) )
2nd hesp male ...most likely mature, ready n' willing.
3rd ..mac probably, but an hr glass shot would tell the tale. From what I understand variolus have been found down your way.
4th hesp ..most likely. The hr glass screams hesp. The dorsal line is thin like a hesp will occasionally have. As she gets older the dorsal line will recede from the dorsal towards the spinneret usually end result is a faded dot. Shes a keeper.
Last two.. most likely hesperus.

I'm not sure but the red spot just behind the spinnerettes seems to say mactans to me.
Not a good way to ID. Though mactan dorsal lines are usually thicker... most of the time the dot/line next to the spinneret will be the same width as the hr glass.


Also if I'm not mistaken, in hesperus, the hourglass is seperated in the middle while in mactans it isn't
Both species can have seperated hour glasses, though from what I gather with macs it is rare. The "average" hesperus has a full hourglass, but hesps can range from full to having nothing down there.
 
Last edited:

Canth

Arachnolord
Old Timer
Joined
Dec 16, 2005
Messages
655
The 4th an 5th pics are of the same spider. I'll try and get an hourglass shot of the supposed mactans.

Thanks guys :)
 

edesign

AB FB Group Moderatr
Old Timer
Joined
Apr 23, 2004
Messages
2,110
I just brought home an L. mactans like the one in your third pic :) Well...earlier this week anyway
 

Python

Arachnolord
Old Timer
Joined
Mar 21, 2005
Messages
631
Not a good way to ID. Though mactan dorsal lines are usually thicker... most of the time the dot/line next to the spinneret will be the same width as the hr glass.
I'm curious now to know what the differences are between the two. Is there a reliable way to tell? I had always read that the hourglass was the biggest difference but now I'm not sure.



Both species can have seperated hour glasses, though from what I gather with macs it is rare. The "average" hesperus has a full hourglass, but hesps can range from full to having nothing down there.
That actually makes sense since not too long ago, I found a widow that had a split hourglass and I'm not in hesp territory. I thought for sure it was a mactans when I found it but when I saw the division there, I found myself second guessing.
 

David_F

Arachnoprince
Old Timer
Joined
Feb 9, 2004
Messages
1,767
I'm curious now to know what the differences are between the two. Is there a reliable way to tell? I had always read that the hourglass was the biggest difference but now I'm not sure.
Spermatheca and palpal emboli differences. There are pattern differences as well, as buthus mentioned, but the best way to tell, as it seems with any spider, is by examining sexual organs. Good luck with that. Patterns and locality seem to be the defining factor for hobbyists.

I wouldn't be surprised if the spiders Jared has are intergrades. The unknown adult seems to have characteristics of both mactans and hesperus.
 

Python

Arachnolord
Old Timer
Joined
Mar 21, 2005
Messages
631
I believe I'll just stick with the notion of locality for now lol. My eyes are nowhere near good enough to check the sexual organs on something that small! At least now I know though so if I ever get a microscope, I'll be able to tell the difference!
 

tom

Arachnosquire
Old Timer
Joined
Mar 19, 2005
Messages
104
latrodectus id

I have some interesting times also verifying the species L.hesperus from L.mactans,as they are DNA related,colour morphs do exist. especially in Lousianna,where a coffee coloured abdomned specimen was thought to be L.texanus before synomy with L.hesperus. I wonder if regional insect diet and locale :desert /savannah or urban areas may affect the spiders in some way. Texas seems to have L.mactans,L.variolus and L.hesperus plus introduced L.geometricus as Latrodectus populations.Just had to comment. Cheers ,Tom.
 

buthus

Arachnoprince
Old Timer
Joined
Jun 8, 2006
Messages
1,381
Correction to my statement...
Not a good way to ID. Though mactan dorsal lines are usually thicker... most of the time the dot/line next to the spinneret will be the same width as the hr glass.
I should NOT have said "most of the time". Their dorsal lines/spots CAN be as wide as their hourglass. Nevertheless, macs dorsal markings are much thicker than that of hesperus.

That actually makes sense since not too long ago, I found a widow that had a split hourglass and I'm not in hesp territory. I thought for sure it was a mactans when I found it but when I saw the division there, I found myself second guessing
If you live in mactan country, you probably live in variolus country also. A split hourglass would point towards variolus until proven otherwise. ...esp if the split was a clear gap.

I wouldn't be surprised if the spiders Jared has are intergrades. The unknown adult seems to have characteristics of both mactans and hesperus.
Interesting.
But, I have raised sacs from both the classic black hesps and from the browns w/retained dorsal markings and I have found both can and do produce young of both flavors. (also including the in-betweens)
I have to suspect that for the sake of specie survival within a given environment a small amount of these more unusual color variants emerge from any given gene pool. Looking at different species from around the globe, one notices that even though all latros start off with basically the same markings, the markings they retain after final molt seems mostly due to the amount of humidity/rainfall. The more the rainfall, the more plant life, the more diversity of potential predators. Woodland and jungle species seem to be the most colorful (with some exceptions of course). Predators within such environments have more prey options, thus more likely to skip eating something with nasty bright warning colors. Old world arid/desert species have gone all black (one went white, but that exception almost seems like an even more "clever" adaption for the same problem). These have even lost their hourglass. Predators in those environments have far less prey options ...so why bother advertising danger if it only leads to you being eaten?
Hesperus and mactans (but esp hesps) are still trying to work this dilemma out. Thats why I get excited when I find colorful oddball hesperus and at the same time I have been searching for the elusive hesperus with NO hrglass. Andrew found one with 0 hourglass and gave it to me. She came from a nasty dry place. Evidence for the above "theory"? ...maybe, maybe not... but at the very least fuel for speculation.
 
Last edited:

Python

Arachnolord
Old Timer
Joined
Mar 21, 2005
Messages
631
That's a great theory. It makes sense to me that colors would be more drab in an arid environment where colors would just advertise an easy meal. Now that you mention it, I have noticed that most desert species are less colorful, even the birds are drab.

Sadly, where I live we only have mactans. I would love to have some other species living around here but so far I've found nothing but mactans, and I've never heard of any other species being local. I guess I'm too far south for the northerns, and too far east for the westerns.

Great info Buthus, keep it coming. I'm always looking to learn more about widows but it's hard to sift through the info to know what's bona fide. Thanks for the lesson, I'll put it to good use.
 

buthus

Arachnoprince
Old Timer
Joined
Jun 8, 2006
Messages
1,381
Great info Buthus, keep it coming. I'm always looking to learn more about widows but it's hard to sift through the info to know what's bona fide. Thanks for the lesson, I'll put it to good use.
Thanks, but please categorize my shat under "boneheada fide" which doesnt even exist on the same plane as "bona fide". If the two planes ever collide, well, I dont know what would happen... probably the end of the hobby as we know it or something. ;) :D
 

Canth

Arachnolord
Old Timer
Joined
Dec 16, 2005
Messages
655
Well it's official. That patterned one at the top is an adult. She just made an eggsac. As did the supposed mactans. I'm so excited! Pics to come tomorrow when I'm not supposed to be sleeping. :D
 

Canth

Arachnolord
Old Timer
Joined
Dec 16, 2005
Messages
655
Got pics. The first one is the patterned female. The 2nd is the supposed mactans


 

8+)

Arachnolord
Old Timer
Joined
Feb 21, 2007
Messages
645
Wonder if I can talk my wife into moving to Texas?
 

Canth

Arachnolord
Old Timer
Joined
Dec 16, 2005
Messages
655
Haha. It's nice here. I might be passing through the same area that these were caught, soon. I will deffinately be looking for more.
 
Top