The magic of the light spectrum

TRection

Arachnoknight
Joined
Apr 19, 2017
Messages
271
I have heard a few people say that T's cant see red light, and others say they can, but what about other colors? what are your takes on this and have you tested different colors of light, if so, what effects did it have on your Ts in terms of activity?
 

Ungoliant

Malleus Aranearum
Staff member
Joined
Mar 7, 2012
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3,825
I have heard a few people say that T's cant see red light, and others say they can, but what about other colors? what are your takes on this and have you tested different colors of light, if so, what effects did it have on your Ts in terms of activity?
I don't know how well tarantula vision in particular has been studied, although the anatomy of their eyes -- as well as their behavior -- suggests they have poor vision.

For a discussion of how spider vision is assessed, see this post.

Some comments from Biology of Spiders:

Biology of Spiders said:
In most spiders the sense of vision plays only a minor role in behavior. Many spiders are active at night and are thus more dependent on tactile and chemical cues than on sight. For web spiders, visual stimuli seem to be especially unnecessary, since these spiders can build their webs at night and catch their prey in total darkness. But to conclude from these observations that vision is irrelevant for such spiders would be premature. The orb weaver Araneus sexpunctatus (synonym Nuctanea umbratica) can detect very subtle changes in light intensity; the time it leaves its retreat in the evening is apparently closely related to the diminishing light at dusk. Other orb weavers drop very quickly out of the hubs if their webs when an observer approaches them, and this behavior is most likely a response to visual stimuli alone.

Vision is important to some spiders other than orb weavers. Sheet-web spiders (Agelenidae) and wolf spiders (Lycosidae) can perceive polarized light, and they use it to orient themselves. For most modern hunting spiders (Lycosidae, Thomisidae, Salticidae), the sense of vision is important, not only for capturing prey but also for recognizing the opposite sex during courtship.
Biology of Spiders said:
Finally, even in some spiders that are not renowned for their visual system (in this case, large tarantulas), a discrimination of polarized light was demonstrated in behavioral experiments.
Biology of Spiders said:
That jumping spiders are often conspicuously colored has been noted repeatedly as an indirect argument for their color vision. This seems reasonable, since in fish and birds a colorful phenotype is often correlated with the ability to differentiate colors. Somewhat more convincing evidence comes from behavioral experiments in which jumping spiders could distinguish blue and orange paper strips from 26 shades of gray. The sensitivities of the main eyes to different parts of the visible spectrum further argue for color vision.
Biology of Spiders said:
Most spider eyes seem to be insensitive to red light, as are most insect eyes. A spectral sensitivity between 330 and 700 nm was found in the jumping spider Maevia. However, the sensitivity was much reduced around 700 nm (i.e., in the red part of the spectrum).
Jumping spiders are capable of seeing UV light.
 

TRection

Arachnoknight
Joined
Apr 19, 2017
Messages
271
I don't know how well tarantula vision in particular have been studied, although the anatomy of their eyes -- as well as their behavior -- suggests they have poor vision.

For a discussion of how spider vision is assessed, see this post.

Some comments from Biology of Spiders:









Jumping spiders are capable of seeing UV light.
:D thank you!
 

nicodimus22

Arachnomancer
Arachnosupporter
Joined
Sep 26, 2013
Messages
709
I use a red flashlight to peek at my crew every night. As far as I can tell, they've never noticed it. I have two VERY photosensitive Ts (Nhandu tripepii and Pterinopelma sazimai slings) that bolt into their burrows the second I turn the normal lights on. They go about their business as normal when I'm using the red light. Haven't tried any other colors.
 

Nixphat

Arachnosquire
Joined
Oct 8, 2016
Messages
62
Only thing I've noticed from a red light is that my sling reacts to it.. not necessarily in a bad way, but when I shine the light in, the sling walks forward out into the open (especially when she's(it's) hungry). @viper69 I had read uses a blue light that works better as far as seeing your T. I've been meaning to look into that more lately but haven't had the chance :)
 

Aaronsp10

ARACHNERD
Joined
Apr 16, 2017
Messages
58
I have red led lights built into my shelving... and a lot of my t's wait till its dark ( only red light) to cruise around... i only see my Hmac at night this way
 

viper69

ArachnoGod
Old Timer
Joined
Dec 8, 2006
Messages
11,521
Only thing I've noticed from a red light is that my sling reacts to it.. not necessarily in a bad way, but when I shine the light in, the sling walks forward out into the open (especially when she's(it's) hungry). @viper69 I had read uses a blue light that works better as far as seeing your T. I've been meaning to look into that more lately but haven't had the chance :)

Your observation doesn't make sense as the scientific literature indicates that tarantulas, well at least one species, and likely the rest, do not see red. I do not think they are seeing red at all based on the scientific paper.

Blue light works betters. Us reptile people know this, and have been using it for years! Red is so 1960s.
 

Nosiris

Arachnosquire
Joined
Aug 5, 2014
Messages
62
I too use a red torch to stalk my Ts during the night. None of them are bothered by it. If I turn a white light on the nervous types disappear.
 

Nixphat

Arachnosquire
Joined
Oct 8, 2016
Messages
62
Your observation doesn't make sense as the scientific literature indicates that tarantulas, well at least one species, and likely the rest, do not see red. I do not think they are seeing red at all based on the scientific paper.

Blue light works betters. Us reptile people know this, and have been using it for years! Red is so 1960s.
Yeah, my other two tarantulas have no reaction, it's either the cheapy light I'm using (a red light on a head light from walmart), or total coincidence that she comes out of hiding when I shine a red light in her enclosure. Either way, yeah, I thought I had read you saying blue lights were better :D
 

viper69

ArachnoGod
Old Timer
Joined
Dec 8, 2006
Messages
11,521
Yeah, my other two tarantulas have no reaction, it's either the cheapy light I'm using (a red light on a head light from walmart), or total coincidence that she comes out of hiding when I shine a red light in her enclosure. Either way, yeah, I thought I had read you saying blue lights were better :D
Blue is better for human eyes to see through. Human's don't see that well in red light. Ts are not affected by red light according to scientists. So it's merely coincidence on your part.

And by blue, I'm really referring to a hue of blue that is used in reptile "moonlight" bulbs. They work great.
 

ThisMeansWAR

Arachnosquire
Joined
Jan 26, 2017
Messages
97
According to TTKG they are especially sensitive to blacklight so using that with an enclosure is supposed to be very disturbing for the animals.
 
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