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PING Bug Girl - Another Arachnid Q

NoZed Avenger

Penultimate Amazing
N
Joined
Apr 19, 2002
Messages
11,286
Bug Girl:

I have a small web spinner out front on the porch, and was wondering if you had any idea what it is.

It is slightly smaller than the nail on my pinky, and colored like a lady bug.

It has what looks like a carapice that is reddish (a little orange-y in the red) with some black spots. The carpice has 6 points on it, at 10, 8:30, 7, 5,3:30, and 2 o'clock. It is industrious -- has a good size web.

I have never seen one like it (Central Texas area).

Any clue? I have tried some rudimentary searches without any luck.

N/A
 
Ok, looks like it is probably a spinybacked orbweaver, Gasteracantha cancriformis.

I refined my search a bit and the description seems to fit.

It also ranges in Texas, so looks like a good fit.

N/A
 
I'm no bug doctor, but I am an enthusiast. Everything I have ever read about spider identification, beyond families has said that one needs a microscope to identify the genus and specie, though something like orb weaver or jumping spider are not so involved, just not precise.

Spiders are COOL.
 
c0rbin said:

Spiders are COOL.
Click to expand...

I hate spiders.

Whenever I see one in the house, I always suck it up with the vaccum cleaner.

Then, just in case it still survived, I will suck up a bunch of pop-corn kernels to pummel it in the vaccum cleaner bag.
 
NoZed Avenger said:
Ok, looks like it is probably a spinybacked orbweaver, Gasteracantha cancriformis.
It also ranges in Texas, so looks like a good fit.
N/A
Click to expand...

oh yeah, it's a.....
dang. never mind. :D

But c0rbin is correct, you can't be 100% sure about genus and species without a detailed examination.
 
Bug Girl more questions:

mr. Hoyt posted the following on a thread in the sceptical forum about biomagnetics. Apparently Roger Coghill said that bugs such as butterflies (moths?) can sense IR. Apparently mr. Hoyt does not believe it. I checked and found hundreds of references that they do. Is this correct? The refs also said pythons have infra red sensing organs around their mouth and rattlesnakes have IR sensing organs on their face.

Perhaps you can settle this argument...can some bugs such as butterflies sense IR and if so, what purpose does it serve them? Thanks. vanessa

Here's what mr. hoyt wrote:

--------------------------------------------------------------------------------
Originally posted by cogreslab

My point is that insects can be regarded as flying IR spectrophotometers,
--------------------------------------------------------------------------------


hoyt:

Hey, look, kids! I've got this thin little glass tube here that I filled with mercury. Voila! Spectrophotometer!


Roger, do they put you in a corner at IoB meetings and only let you out for milk and cookies?
 
I do know that some insects that like to eat from flowers can see in ultra violet, but that's at the other end of the visible spectrum.

I also know that pythons and some boas do indeed have infrared detectors, heat sensitive pits, on their lower jaw.

As for rattlers and insects seeing in IR, I just don't know.
 
Rattler snakes are pit vipers. Pit vipers have heat-sensitive pits on their faces. I don't know if they count as "seeing" - I'm not sure they form an image so much as give the snake a general idea of where to find the warm tasty snack.

A cursory Google searched turned up a Dr. Schmitz who's apparently published a number of papers on infrared sensitivity in insects: http://www.zoologie.uni-bonn.de/Neurophysiologie/home/Schmitz/PublikationenD.htm but I didn't find a whole lot else.

Edit to add: I believe birds (some? all?) can see into near UV as well, and some bird plumage is very reflective in UV.
 
Segnosaur said:


I hate spiders.

Whenever I see one in the house, I always suck it up with the vaccum cleaner.

Then, just in case it still survived, I will suck up a bunch of pop-corn kernels to pummel it in the vaccum cleaner bag.
Click to expand...

Idiot.
 
materia3 said:
Bug Girl more questions:

mr. Hoyt posted the following on a thread in the sceptical forum about biomagnetics. Apparently Roger Coghill said that bugs such as butterflies (moths?) can sense IR. Apparently mr. Hoyt does not believe it. I checked and found hundreds of references that they do. Is this correct?
Perhaps you can settle this argument...can some bugs such as butterflies sense IR and if so, what purpose does it serve them? Thanks. vanessa
Click to expand...

Well. my answer will probaby be somewhat suspect, since i think Bill is a complete and utter git.
Having revealed my biases:) :
It's actually not an easy question. Insects are very sensitive to the ultraviolet end of the spectrum. Here's a great, detailed summary of insect vision from a leading insect physiologist: http://www.faculty.ucr.edu/~insects/pages/teachingresources/tmlectures/vision.html

On the IR end there is less evidence:
"Since insects see color, they are sensitive to green, blue or ultraviolet, and thus view the world at the blue end of the spectrum. Some insects are suspected of being insensitive to much of the red end of the spectrum, and many are thought to be blind to infrared light, although exceptions are now known. "

Quite a few butterflies respond to red, although not Infrared, as far as i know. Research on insect vision has really taken off in the last decade, as new instrumentation becomes available. Most of the references i found were for the Catocala genus, which is a really nifty little group of moths.

I haven't read this, but did see it in my library:
Hsiao, H. S. 1972. Attraction of Moths to Light and to Infrared Radiation. San Francisco Press, San Francisco. 89 pp.

Since moths are mostly nocturnal, IR could make some sense if you are flying around at night.
 
materia3 said:
mr. Hoyt posted the following on a thread in the sceptical forum about biomagnetics. Apparently Roger Coghill said that bugs such as butterflies (moths?) can sense IR. Apparently mr. Hoyt does not believe it. ........ [/B]
Click to expand...
Far be it from me to defend Bill Hoyt but

THe link

http://host.randi.org/vbulletin/postings.php?s=&action=getip&postid=1870477315

Roger Coghill's assertion was that moths used IR as a means of comunication and that they could control their body temperatures so as to modulate the frequency of their black body radiation to achieve this communication.

It was this suggestion, I believe, which produced the response from Bill Hoyt, not whether or not months could sense in the IR range.

It would be amazing if they could detect the difference in frequency which would result from a marginal difference in temperature
 
Thanks BugGirl and Don helping to clarify this. In google I found 463 links on the subject of IR reception in insects and some on rattlesnakes, plus many other kinds of pit vipers and the python snakes. I saw research papers by Schmitz in Germany also, thanks Zombi.

I didnt see nor could I access the link you give Don where Coghill says this is a sense used for communication. I guess some senses are adjuncts to communication like hearing (obviously), seeing (visual signals) and feeling (braille comes to mind...) but this particular sense seems more related to locating prey, identifying enemies and finding spots to thermoregulate since both insects and reptiles are ectotherms.

Zombified wrote: "I don't know if they count as "seeing" - I'm not sure they form an image so much as give the snake a general idea of where to find the warm tasty snack."

I remember seeing a program on Discovery about pit vipers including rattlesnakes. As I recall researchers said snakes have lousy eyesight and detect prey (warm blooded rodents) by flicking their tongue out and sampling air and ground for prey odours. They have special organ for this called vomeronasal organ. But rattlesnakes and other pit vipers and pythons have additional benefit of IR sensing organs. They blindfolded rattlesnakes and surgically removed their vomeronasal organs and they were still able to detect and strike at warm blooded prey accurately. They showed thermal image of mouse which snake is supposed to see very much like thermal image we see with cameras that do this. I don't know how researchers know what snake actually "sees" but they used their strike accuracy to determine that they evidently see their target in this manner depending on how you want to define term "see."
 
materia3 said:
Bug Girl more questions:

mr. Hoyt posted the following on a thread in the sceptical forum about biomagnetics. Apparently Roger Coghill said that bugs such as butterflies (moths?) can sense IR. Apparently mr. Hoyt does not believe it. I checked and found hundreds of references that they do. Is this correct? The refs also said pythons have infra red sensing organs around their mouth and rattlesnakes have IR sensing organs on their face.

Perhaps you can settle this argument...can some bugs such as butterflies sense IR and if so, what purpose does it serve them? Thanks. vanessa

Here's what mr. hoyt wrote:

--------------------------------------------------------------------------------
Originally posted by cogreslab

My point is that insects can be regarded as flying IR spectrophotometers,
--------------------------------------------------------------------------------


hoyt:

Hey, look, kids! I've got this thin little glass tube here that I filled with mercury. Voila! Spectrophotometer!


Roger, do they put you in a corner at IoB meetings and only let you out for milk and cookies?
Click to expand...

You insist on this distortion of what I wrote and misrepresentation of what coghill wrote. Coghill wrote that they are spectrophotometers. Read the quote you presented here. The evidence he presented demonstrates they can detect IR. I never disputed that. Read the quotes you presented here. My point here, and on the original thread, is that photodetection is not the same as spectrophotometry.
 
materia3 said:
Thanks BugGirl and Don helping to clarify this. In google I found 463 links on the subject of IR reception in insects and
Click to expand...

Yes, but most of those are for *use* of IR in the monitoring of insect flight. The paper i looked at had data for responses to IR in one genus of moth, and speculated this had to do with bat predation. However, this is different than linking IR to bat avoidance--and that would be an extremely difficult task. I think until more information is in about moth vision, this will be an unanswered question.

Insects do thermoregulate all the time, and have many different mechanisms to do this.
 
bug_girl said:


Yes, but most of those are for *use* of IR in the monitoring of insect flight. The paper i looked at had data for responses to IR in one genus of moth, and speculated this had to do with bat predation. However, this is different than linking IR to bat avoidance--and that would be an extremely difficult task. I think until more information is in about moth vision, this will be an unanswered question.

Insects do thermoregulate all the time, and have many different mechanisms to do this.
Click to expand...

Thanks again. The main work on IR reception seem to be by Schmitz in Germany and Callahan. Coghill provided a reference and brief quote by Callahan: Ann Entomol Soc Amer-58(5):729-45 (in the other thread) where he calls noctuids flying spectrophotometers and FIR transmitters and receivers.

Correct me if I am wrong but this seems to be precisely what Hoyt was looking for, or I should say, pestering and badgering Coghill about. Coghill, after about 24 hours provided the reference.

What bugs with these abilities do with them, what their function is, seems to be undecided as you say. Empircally, such abilities evolved to do something.
 
materia3 said:
Thanks again. The main work on IR reception seem to be by Schmitz in Germany and Callahan. Coghill provided a reference and brief quote by Callahan: Ann Entomol Soc Amer-58(5):729-45 (in the other thread) where he calls noctuids flying spectrophotometers and FIR transmitters and receivers.
Click to expand...
a reference! Now i have something to work with. .....

Except i'm not at work, which is where my Annals are.
sometime next week i'll see if i can find that.
 
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