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Pedipalp, distoventral view - Latrodectus hesperus - male

Pedipalp, distoventral view - Latrodectus hesperus - Male
Las Vegas Wash within the Clark County Wetlands Park, Clark County, Nevada, USA
July 7, 2011
Size: 4 mm
Showing the 3+ turns of the unbroken embolus. The palp is rather large, relative to the spider; diameter of the embolus loops is approx. 0.6 mm.

Specimen collected by J. Eckberg:

Images of this individual: tag all
Pedipalp, distoventral view - Latrodectus hesperus - male Pedipalp, mesal view - Latrodectus hesperus - male Pedipalp,

Wow, nice!!
I wonder what this looks like during the mating "process"...

Very nice
Stacked images, I assume? What magnification and camera are you using? I think it's about time to upgrade my "hold a point-and-click camera up to the eyepiece" method for palp and epigyne pictures.

This sort of detail is very useful. I'd be especially interested in similar images of the other four NA species, for comparison.

There is a distinct beauty to spiders at the microscopic level. I wonder what mathematical formula would describe the spiral of that embolus?

Thanks. Yes, stacked images.
Thanks. Yes, stacked images. Here the magnifcation was only maybe 30-35x because the pedipalp was so large. I thought you were already using a trinoscope. Mandy is using the same approach as you, but I think she has some sort of attachment device (or tripod?) -- I'm not sure. Perhaps I can talk here into posting something about her set-up in the Forum (I just helped her fix some lighting issues via PM).

I can't help with the mathematical formula, but agree about the beauty of these structures.

I still can't believe how long I stared at this specimen before I made the connection with Latrodectus -- I finally did an online search for "three loops embolus pedipalp" and came up with an article about a Latrodectus species in Pakistan; this finally rang a bell upstairs with me.

I told John a little while back about getting all the "black" images from the microscope shots. It's fixed now, though! I have to thank Kevin for that. In a single email, everything I had been struggling with for months and months was suddenly easy! :-) (I just had all the camera settings wrong & also was not submerging the spider in enough alcohol.) I did buy a camera mount that clamps onto the microscope eyepiece, which allows me to use a longer shutter speed and get more light on the images without them being too blurry from hand-holding the camera (this is the mount I have). Next week I plan on getting a trino 'scope, though, which has a higher magnification than what I have now and I suspect that having the 3rd eyepiece for the camera is going to be really handy.

I have always envied both of your shots and am so excited to finally be able to take some images myself. At least I can see what's in them now! Yay! :-)

I posted some of this in the Forum -- I hope it's okay that I uploaded your test images?

Totally fine
I hope they help anyone else that is having the same trouble, so I am happy to be a test subject! :-)

> I thought you were already using a trinoscope

No, but it's on my wish list.

>I still can't believe how long I stared at this specimen before I made the connection with Latrodectus

Been there, done that! I once spent a few days trying to figure out what kind of araneid a Pityohyphantes costatus specimen was. :)

I may be wrong, but I think the easiest way to recognize the Latrodectus genus (once you know you've got a theridiid of some kind) is from the arrangement of the PLE and ALE, which are separated from each other by about the diameter of an eye. Mandy can double-check me on this, but I think that feature distinguishes Latrodectus from just about all other theridiid genera in NA.

I use the eyes to separate Steatoda from Latrodectus (in instances where that's all I have to work with; i.e. frontal images)... but I can't say that I know for sure if Latrodectus is the only one in the whole family with the separated lateral eyes. I do think so, but I've never specifically researched it, so don't want to commit all the way. (By the way, I have always felt that you two are much more experienced than me! Hearing "Mandy can double-check me" was kind of a shock, haha, but a flattering one)

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