Spiders page 2 (Nephila clavipes)
Spiders page 4 (Jumping Spiders)
Spiders page 5 (Orb Weavers)
Spiders Page 6(fishing spiders)
Spiders Page 7(spitting spiders)
at Brazos Bend State Park Introduction
Critters at Brazos
Bend State Park Page 1
Snakes-nonvenomous 1------------------------------------------- Critters at Brazos Bend State Park Page 3
Snakes-nonvenomous 2-------------------------------------------------Insects, non-toxic
This is my third page of information I've found about spiders. Most of these pictures were taken at Brazos Bend State Park. I hope that, like me, the next time you see a spider (and they are almost everywhere), you'll take a second to admire their form and function.
morning, it started raining just as I pulled into the park. However,
that doesn't mean that I couldn't find evidence of hunting around me anyway.
The image below (HOW DID THIS HAPPEN?) shows what must have seemed like
a very lopsided battle with a surprise ending. The small, round spider
is probably a Common House Spider (Achaearanea tepidariorum). These
are generally the culprits who make those tangled cobwebs in corners. Unlike
some of our other spiders (like the Nephila Clavipes, or Golden Silk Spider),
this spider appears to suck the softened bodily fluids from small holes
in the exoskeleton of its prey. From what I can find, this is a female,
and she is extremely full. The three images below (EATING 01,02,03) are
closeup views of her as she daintily takes her meal.
HOW DID *THIS* HAPPEN? EATING 01 EATING 02 EATING 03 C
larger spider is kind of hard to identify, but from the position of the
legs, and by the general appearance, I'm pretty sure it's part of that
rather large group of spiders that are sometimes known as Aranea Mortuus---or
Update 11/19/03--Ok, I thought the dead spider thing was funny. But, I started wondering about what kind of spider this might actually have been before it became an "aranea mortuus". It's probably the same type that we've seen with their sparse webbing around various notholes and crevices both inside and outside the VC/NC at Brazos Bend State Park. Since I didn't take any pictures of the dead spider's face, I'm only guessing though. I think that I'm looking at a Southern House Spider (according to "A Field Guide to Spiders and Scorpions of Texas, by John A. Jackman); also known as Kukulcania hibernalis (Or perhaps in this case "Kukulcania hibernalis mortuus? HA!). In the image "CREVICE WEAVER" above; strands of the webbing are visible to the right. This spider will spin a sort of open "funnel" into a hole or crevice, with the loose flat strands radiating out around this hideout. Passing prey can walk upon these tripwires, which will alert the spider to run out and attack. I took this picture September of 2002, when the spider was next to one of our windows at the VC/NC. The eyes of this spider are supposed to be close together, but I haven't inspected one in enough detail to tell. The female is the large (13-19mm), dark one I have pictured. The male is about half this size (9-10mm), with a generally thinner body that is lighter in color.
Now that we're looking at it, why do spiders' legs curl up like that when they die? Well, that's pretty interesting. As in the past, I went to the book Biology of Spiders, by Rainer F. Foelix, published in 1996 for an answer. Spiders' legs, as I've mentioned before, are composed of seven segments. That means that there are six articulations, or joints between them (see LEG SEGMENTS, below). For general body part names, see BODY PARTS, below. Although I used the Folix book for a reference while I made these images, any mistakes that may be apparent are surely mine.
BODY PARTS LEG SEGMENTS HYDRAULIC PUMP
Now, most animals have two sets of opposing muscles that operate their joints. Flexors, which bend them, and extensors, which straighten them. In the spider leg, with six joints, there are two joints which do NOT have extensor muscles (from the tip of the leg, this is joint number 2, and joint number 4. see HYDRAULIC PUMP, above). That means that there are no muscles to straighten those joints! How then, can the spider straighten its legs?
While you take a moment to wonder about that, consider that spiders not only possess an exoskeleton (the "armor"), but they also have a sort of endoskeleton, or inner structural supports as well. They are called "endosterna". These serve as attachment points for certain muscle groups (entosternal muscles).
Largest of the structures of this endoskeleton is shallow cuplike construction that sort of bisects the cephalothorax (prosoma) horizontally. This is called the "endosternite". There are groups of muscles that attach this structure to the carapace (upper surface) and sternum (lower surface) of the prosoma. The picture I made above shows these in VERY simplified form. If you are interested, find the book and look at the professional version. These muscles can move the endosternite, which can lower the volume inside the cephalothorax. Doing this can increase the fluid pressure inside the spider. This is similar to you squeezing a toothpaste tube which lowers the volume, which increases the pressure, and forces the toothpaste out . This increase in fluid pressure acts like a hydraulic pump; and this is what extends the second and fourth leg joints. Without the pressure the legs will fold, if the muscles contract, and stay folded.
While this seems like an odd arrangement to me, spiders were here long before I was, so glitches in the design must have been worked out by now. Pretty complicated creatures...these "simple", "primitive" spiders.
I am able to find the creature I wanted to see, and take photos of it.
Today was such an occassion. A cold front was due to hit the park around
noon today, dropping the temperature at least 20 degrees (that's from around
70F to 50F for you northerners), with more severe drops overnight. I'd
hoped to be able to find a few spiders before they were possibly killed
by a freeze. My target today was the Southern House Spider (Kukulcania
hibernalis), which has webs all over the VC/NC--both inside and outside
the building. I found a willing subject in our Volunteer Lounge.
WHO'S OUT HERE? LEFT FRONT LEG HER CHARMING FACE HER SIZE
She was poised outside her hole, but when I turned on the lights. she went inside. Some gentle probing persuaded her to come back out, and I took a lot of pictures. The picture below (STRETCHED OUT) shows a good full-body picture, as she started moving back towards her funnel. WHO'S OUT THERE (above) shows her coming out of the hole. Note the widely-spaced web strands, and the loose funnel of her home that is visible in some of these images (and the clips). The next image, LEFT FRONT (above) shows a closer view of the left leg in the first image. The two claws at the end of the leg are visible. HER CHARMING FACE (above) shows the long pedipalps (appendages in front of the head), and the eyes arranged in a close group. The whiteness of some of the eyes is due to reflection from the camera flash. When possible, I like to show something with the spider for scale, and HER SIZE (above) shows her with a quarter. Through all of this, she was very cooperative. The sunken condition of her abdomen probably shows that she hasn't eaten for a while, though. I took a view short clips with the digital camera, also. The images below are a single frame from each clip, and clicking the image will show the clip. The first one (CHECKING THE WEB) shows her pulling on the strands of the web. The second one (GOING BACK HOME) shows her as she decides she's had enough photography. I was using a flashlight for illumination so the lighting shifts a lot.
--------- CHECKING THE WEB (flv video 329 kb) STRETCHED OUT GOING BACK HOME (flv video 253 kb)
March 07, 2004 The image below (THEY SING) shows a cluster of baby spiders. They appeared to come from an egg case which I'd assumed belonged to my favorite spider, the Golden Silk Spider--Nephila Clavipes. But, I'm not so sure, judging by the bulbous abdomen that they show. The image below (AREN'T THEY CUTE?) is a close-up of some of these spiders, while the image below (JUST HAVE TO PET THEM) is an image from a short video clip (flv video 218 kb) of them responding to my finger. Isn't it interesting how they move in unison? It's hard to focus on such a mass of small objects, and I was reluctant to separate any from the stack, so I don't have a very good image of a single spider.
THEY SING ABOUT THESE? AREN'T THEY CUTE? JUST HAVE TO PET THEM
December 12, 2004Later that afternoon, I went to the VC/NC for a while. While I was there, I decided to try to get pictures of our tarantula. According to my Field Guide to Spiders and Scorpions of Texas, by John A. Jackman, the tarantulas are in the genus Aphonopelma and there are 14 species that are difficult to tell apart. So, I'll just go with "tarantula".
I'm trying to put together a presentation about spiders, and thought some closeups of a tarantula, which is normally considered a "primitive" spider would be good to contrast with other, more common types. Also, I figured it was about time to handle that particular spider, since I hadn't before.
Unfortunately, the lighting in the VC/NC and perhaps the fuzziness of the spider's outline made it difficult to focus my camera--especially since I was holding the spider in my other hand.
She (she's a number of years old, and therefore must be female, since male tarantulas don't live that long), was content to stay on her piece of bark at first (see RESTING, below). As I held her bark quietly, from time to time, she'd take a few tentative steps onto my hand. She seemed to be uncomfortable with the texture of my skin ("eww...it's...NOT HAIRY!") and would step on, then step back off. Finally, she decided to walk onto my hand (it took at least 10 minutes). Once she started walking, she kept on, though. (see I CAN WALK ON THIS below, or this short video clip, 692 kb). So, for a while, I let her walk up one arm, onto my right hand, then back onto left hand and back up my arm. I thought I detected a slight hesitation when she first encountered my arm hairs (see EWW!, THIS ARM IS...HAIRY, below, or this short video clip, 459 kb).
While this was going on, from time to time I'd grab my camera and take a picture, but only got a few usable ones, (see WRIST WATCHING and GIVE ME 5, below). Finally, I put her back into her cage, where she immediately rested. I liked
our little encounter. I hope she did.
RESTING I CAN WALK ON THIS! EWW!, THIS ARM IS...HAIRY WRIST WATCHING GIVE ME FIVE...ER...EIGHT
video clip 692 kb video clip 459 kb
another Easter at BBSP. When I walked into the VC this morning, there was
lots of talk about a mysterious spider on one of the benches on the deck.
At first glance, it looked like some kind of bird's poop. Well it
DID, don't give me that look. Anyway, when I saw it, I guessed that it
was a Bolas Spider--only because I'd thought something else looked
like one last year, and I looked at lots of pictures of them then. It was
just a lucky coincidence that this one happened along. Chuck Duplant pointed
out an egg case that belonged to it.
Then, Chuck and I went into our VC library and searched through everything we could find for a picture of a bolas spider. No dice, until a look in
the "Biology of Spiders" (by Foelix) book gave us the scientific name "mastophora" (it's on page 147, with a picture on page 171). AHA! Then, Chuck
got on the internet while I got some more pictures in the books in our library. We're pretty sure that it is indeed a Bolas Spider.
WHAT'S THAT WHITE STUFF? BETTER CLOSEUP VIEW BOLAS SPIDER AND QUARTER BOLAS CLOSE FACE VIEW
I got excited about this because the mastophora is another one of those spiders that uses webbing (and chemical bait!) in a unique way (as opposed to making a snare from an orb web or "cobweb".). It emits pheremones that males of a certain species of moth (Spodoptera) find attractive. This brings the moths near the spider. Meanwhile, the spider extrudes a single strand of silk with a sticky blob on the end. When insects start flying nearby, it hangs down and slings this blob around in circles (looking like one of those gouchos slinging a bolo--except with 4 more limbs) until it hits--and sticks to--a moth. Then it reels in the moth and has a meal. These spider average about 3 moths per night. (--see Foelix, page 171.) The spider is nocturnal, so I didn't have much chance of seeing it in action. So, I looked for a video clip.
I looked all over the internet but couldn't find a video clip of the spider in action. So...I made one. Actually, I pulled the clip out of a short film that
resides in the public domain. I cut this out, and recoded it as small as I could make it. Here's the link to my clip: BOLAS 04/17/06 WMV 2660MB
The images below are frames from the clip. Unfortunately, the spider is fed a moth by using a set of tweezers, so we don't get to see the slinging of the bolas.
MAKING THE BALL LET OUT THE LINE GO GRAB THE END READY TO SLING
of the original film is "Spider Engineers", 1956. At that time, the pheromone
discovery hadn't been made yet, so the original film clip indicates the
baiting mechanism is unknown. I've edited in a short note telling about
the pheremone discovery. This editing of the original public domain
material gives me ownership of the new video clip. The entire
short film can be found on the internet archive site, and anyone may download
it for free, and use it however they like. That is the only reason I'm
using it here. Since the film is in the public domain, it is
possible to edit and update the film (especially if one doesn't agree with
some of the points in the film) and present it in the updated version.
Thus, the film becomes a different work.
Here's a link to the film: http://www.archive.org/details/SpiderEngine It's downloadable in a number of different formats and sizes, but pay attention to those details. The files are pretty big.
If you'd like to know more about the park follow these links:
Brazos Bend State Park The main page.
Brazos Bend State Park Volunteer's Page The volunteer's main page.
Click on this image to see a flv video movie (942kb) of a series of 9 11 x 14 posters I'm working on.
Go back to my home page, Welcome
Go back to the RICKUBISCAM page.
Go back to the See the World page.