Hourglass of black widow spider

[rjlittlefield]

Live specimen, stack of 119 frames:



In this live animal, there is some irregular movement of the light blobs seen through the red hourglass. Here is an animation of two adjacent frames in the stack:



Background story is that I've always wanted to take a close look at the red hourglass pattern on a black widow spider. So, when this one set up shop just inside my garage door, I talked my wife into letting it stay there until the time was right.

Yesterday the time was right. I transferred the beast to a small plastic container, thinking only to confine it until I could figure out how to photograph it live. To my great good fortune, the spider chose to spin her web right at the top of the bottom section of the box, then finished the gift by positioning herself upside down and sitting still long enough for me to take off the top section of the box, set up a stack, and shoot it.

Right after that, she got quite a bit less cooperative.

Here's an "after the shoot" snapshot. You'll notice that she's not positioned anywhere near the center of the objective. I'm just happy that she's still inside the box!



Getting back to the hourglass, it seems to be composed of a red window over some light-colored globules inside the abdomen. Apparently the globules sit just under the cuticle, since a stereo pair showed very well the hairs sticking up, but hardly any depth below the surface. So I skipped the usual stereo, but I got lucky enough to catch some internal motion between two frames of the stack, which shows up pretty well in the animation.

Canon T1i camera, Mitutoyo M Plan Apo 5X NA 0.14 objective , Raynox DCR-150 tube lens, two Jansjo lamps diffused through kleenex tissue, ISO 100 at 1 second with EFSC, 119 frames at 0.02 mm focus step, shot by hand to avoid StackShot motor noise that I was afraid might spook the subject.

--Rik

Edit: to add explanation of the movement, and frame numbers to the animation.

[zed]

It's really great that you were able to capture details like this in a live specimen. I especially like your clear cuvette solution where you can position the box based on the spider's orientation.

This pulsating effect you see is quite mesmerizing to watch. This past summer I collected a few spiders that had been paralyzed by mud daubers - and watching them in this almost suspended animation state was extraordinary.

Congrats though on illustrating how this type of imaging is possible on live specimens - it would be great to see more of this type of work.

[Lou Jost]

Beautiful and challenging. I have trouble even photographing live flowers,while you are succeeding with live Black Widow Spiders and stinkbugs! Congrats.

[rjlittlefield]

Thanks for the kind words, guys!

zed, the rectangular plastic boxes are something that I've used a long time for storage. The sides can be viewed through with a binocular scope, but photographing through them doesn't work very well because they aren't uniform enough. Most live things that I photograph in the box are done with the box open, like this black widow. For things that I need to shoot through glass, I have a very small cage made of two microscope slides, like for https://www.photomacrography.net/forum/ ... php?t=3699 and https://www.photomacrography.net/forum/ ... hp?t=17295 (images #5 and 6). For somewhat larger things, I have one of the larger rectangular boxes that I've mounted a UV filter in, to serve as an optically clear glass window.

The first thing that I tried with this black widow was to knock her out with CO2 and transfer her to the microscope slide cage for photographing. But that didn't work at all, because when confined that way she wouldn't hold still. So I transferred her back to the storage box while I figured out what to try next, and after a while I noticed that she seemed calm enough to just "go for it". If the black widow had decided to make a run for it while I was shooting the stack, I might have had some difficulty explaining to my wife.

Lou, I'm pretty sure that my live stinkbug is more robust than orchid flowers. The BMSB is still going strong, weeks after the photo shoot, and after shedding its epoxied holding jig. This black widow might even have been more cooperative than a flower. The last time I tried to stack a small flower, it seemed to tremble something awful!

--Rik

[brentbristol]

Wow! Just Wow!

[rjlittlefield]

Brent, thanks for the enthusiastic support!

Update: the spider has now been returned to suitable habitat, but outside the garage instead of inside it. My powers of persuasion do not extend to sharing inside space with black widows.

--Rik

[MarkSturtevant]

Very interesting. I agree the hourglass is likely a clear window in the cuticle.
The pulsing is some sort of breathing? Not sure. Never seen that before with spiders, though of course insects ventilate with movements of their abdomen.

This too is a good demonstration that these spiders are not remarkable in their behavior. Dangerous but not aggressive.

I had an occasion to make a little box out of larger microscope cover slips. Spot-joined together with silicone glue.

Well done!

[rjlittlefield]

Thanks, Mark.

Bear in mind, the apparently "rhythmic" pulsing is a misleading artifact of the flash/flash animated display that I intended only to show movement between two successive frames of the stack.

In the original stack, the movements are irregular and occur mostly between frames, which were shot about 4 seconds apart (with 1 second exposure time).

I've updated the animation shown above, by adding frame numbers.

Here is a longer animation from a little later in the stack, with a pause at the beginning and end.



I hope this helps to clarify!

--Rik

[MarkSturtevant]

That is helpful.

[TheLostVertex]

I always try to do photos of spiders live, so them having a transparent body is often times a challenge. I imagine if you were successful in "knocking her out" you would still have the same issue(maybe to a lesser degree though).

I took a video of one spider some time ago https://streamable.com/gkuyu Its pulse is quite evident

[Tim Boomer]

I know I'm way late to the game, but I just have to say this is absolutely incredible work! Kudos on showing the black widow some love, Rik!

[Sym P. le]

Nice work. Here is a short video I inadvertently took of a Spider pulse https://www.flickr.com/photos/60839073@ ... otostream/. It was news to me when I saw it.

While using focus bracketing, I also became aware of breathing pulses in globular springtails as well and later was able to catch on video https://www.flickr.com/photos/60839073@ ... 297259145/

[rjlittlefield]

Thanks for the kind words!

I have to confess, even though this was only two years ago I seem to have lost all independent memories of this episode. I'm sure glad I wrote it down!

(Oh wait, "Dec 2019". That was not long before covid got distracting, surely the cause of my mental lapses. It makes a good pretense, anyway...)

--Rik

[Olympusman]

BRAVO!
Mike

[Caddo]

Hello,

I'm a long time forum member but only occasional poster. Always enjoy reading everyone's great info and seeing the wonderful images. Now that I'm retired with more time maybe I will post photos more often. This post piqued my interest!

I just thought I would clear up the not unexpected assumptions that the movement seen in the opistosoma (abdomen) of the Black Widow photo of Rik's is not breathing but actually the heart beating, as also may be seen in other spiders which have transparent enough cuticle and areas lacking color. The spider heart is along the dorsal portion of the opistosoma. As with ants which gaster is used for abdomen, in spiders often opistosoma is the term among arachnologists most of the time. (I am not one of them....just passionate amateur)

Spiders do not respire (breath) as we may assume but have two types of "lungs". They are book lungs and tubular tracheae which transfer oxygen from the air to the hemolymph just from passive surrounding airflow. Thus no "breathing" as such. Different spider families may have only two pairs of combinations book lungs (tarantulas for example), others one pair or no book lungs. A limited number of families may only have tubular tracheae or another variation, sieve tracheae.

For the interested you may refer to "Biology of Spiders" Third Edition by Rainer F. Foelix for the full story.

Hope all find this interesting.
Caddo