Why is P. metallica blue?

[becca81]

My husband and I were discussing this question last night and, without doing any research, batted around some ideas.

Many tarantulas are very brightly colored. I'm curious why some are camoflauged so well and others would stick out to a predator. Is the color a warning sign? If so, why are some "pokies" camoflauged and others brightly colored? They have similar predators, right?

P. metallica would be very easy to spot in a tree.

 

[Crotalus]

My husband and I were discussing this question last night and, without doing any research, batted around some ideas.

Many tarantulas are very brightly colored. I'm curious why some are camoflauged so well and others would stick out to a predator. Is the color a warning sign? If so, why are some "pokies" camoflauged and others brightly colored? They have similar predators, right?

P. metallica would be very easy to spot in a tree.

At night the blue color probably works as a camoflage. The bright colors pokes got on ventral side of their legs are used as warning colors to predators visible when the spider rear up.
Why for example some Brachypelma got striking coloration is most likely a warning signal. And the different colors break up the outline of the spider so it may work as camoflage aswell.

/Lelle

 

[becca81]

Which Ts are the most brightly colored?

 

[Brian S]

C fasciatum, B boehmei are brightly colored for sure.

 

[usumbaraboy]

the usumbaras are really brite in colour.

 

[FryLock]

Which Ts are the most brightly colored?

Which ever one's you spray paint i guess .

 

[Bean]

P. metallica would be very easy to spot in a tree.

Going along the lines of what lelle said, I wonder if they would? I'm leaning towards no.

I do know that many times pictures of tarantulas can be misleading, as the flash or other lighting provides an un-natural, sometimes more brilliant appearance. A question for those who keep P. metallica: Are the colors more subdued in natural light?

 

[metallica]

P. metallica would be very easy to spot in a tree.

after dropping a P. metallica in the backyard, i can tell you they are well camouflaged....... yes i did find it back after 15 mins.

Eddy

 

[Wade]

The pattern is probably more important than the color. Consider tigers, here you have a very large, bight orange animal that can virtually dissapear in the forrest due to the striped patter that breaks up the outline.

When viewed up close in a context divorced from it's natural setting, P. metallica stands out. On a tree hunting in it's natural element at night, under the mottled light provided by the moon filtered through leaves, it's probably invisible.

Wade

 

[Freddie]

P. metallica would be very easy to spot in a tree.

At night the blue color probably works as a camoflage.

Blue is the first color that disappear the first in the dark (specially if the night is blue, compare to diving). Black (or red, can't remember) is the color which you can see the longest.

If P. metallica is night active it's pure protective coloring, especially when thinking of pattern.

 

[DracosBana]

You also have to factor in that a lot of other animals are actually color blind. That's why deer hunters can walk around in bright orange without alerting the deer that they're there.

 

[Freddie]

Or was it blue that disappears the last... whatever LOL
Should check somewhere.
But blue is good camoflage in the night time.

Usually complementary colors are those which disappears the first so... (complementary colors against to surrounding environment). Colors are for the protection, warning or "flirting".

 

[mick]

after dropping a P. metallica in the backyard, i can tell you they are well camouflaged....... yes i did find it back after 15 mins.

Eddy

that must be a SCARY feeling losing one of those
Mick

 

[Ultimate Instar]

Although blue may be protective coloration at night, my P. metallicas run around during the day. So either captivity has a weird effect on their behavior, or there is something else going on. Is it definitely known that all Pokies (or all Ts) are nocturnal? Also, if blue is such a great color for night activity, why aren't more animals blue? H. lividum males are blue before their ultimate molt and then turn mostly black before wandering off in search of a mate. For that matter, can anyone explain the color changes in A. versicolor? I wish that more biologists would study Ts (inverts in general, for that matter); they are ancient and highly successful creatures, and they have some very odd behavioral and physiological aspects. Instead, entomologists get paid by pesticide companies who only fund research into better ways to kill insects that eat crops.

Karen N.

 

[tkn0spdr]

I believe that red disappears first as the yellow part of light gets filtered out of the visible spectrum as in your diving example.

 

[Tony]

I know Andrew Smith showed slides of pokies in the wild 'regalis complex' : )
and the black n white pattern made them blend in very very well
T

 

[Michael Jacobi]

This is a very interesting question and many replies, particularly Wade's, have given possible answers. What has always fascinated me is that blue is likely the rarest color in nature - at least out of the sea. Sure there are some striking exceptions: the Azure Blue Dart Frog, the Hyacinth Macaw, bluebirds & buntings, etc. etc., but the number of blue organisms living on land or in the air are proportionately low. Of course, the sea and the sky aren't really blue - it's appears that way due to light refraction.

So how did P. metallica become blue? I have no idea, but remember that most members of the genus have some sort of purple sheen, especially post-molt. This underlying color is often brought out with flash photography or bright sunlight. It's not such a stretch for this color to become blue in a related species.

And why is Haplopelma lividum - a species that spends most of its life underground - part blue? I wish I had more time to ponder these things right now, but in the end it is definitely about pattern, more so than color.

Cheers,

Michael

 

[Martin H.]

BTW, some years ago there had been a similar discussion on the ATS_Enthusiast mailinglist: why is C. cyaneopubescens orange and blue: >>click here<<. One might find some interesting thoughts/suggestions there, like: "... Lets concentrate on what the predator CANNOT see as opposed to what the predator can see. For instance, there have been many studies regarding the color perception of predatory birds. It has been found that they have trouble seeing certain colors, orange being one of these colors as well as blue. Even Owls have poor color reception. ..."

all the best,
Martin

 

[Wade]

It may be a mistake to assume the color has any specific purpose. If the color of P. metallica is not a true pigment and is the result of light refraction as in the case of other blue tarantulas (if it is a true pigment, feel free to enlighten me), it may not mean anything. The structure/composition of the spiders exoskeleton which causes the blue color may have an evolutionary benefit that is not apparent to us. The fact that the structure/composition causes the spider to appear blue may simply be a side effect. In the absence of any evolutionary pressure to NOT be blue, the color remains.

In short, the attractiveness of this spider may be just a coincedence of evolution. A happy coincidence!

Wade

 

[becca81]

In the absence of any evolutionary pressure to NOT be blue, the color remains.


Wade

I've never thought about it this way - how interesting!

I've been thinking along the lines of the colors that are seen by natural predators. If the natural predators are color-blind to any particular colors, it would make sense for a species to evolve towards these colors.

Or, perhaps, the natural predator can see one or two particular colors VERY well, and the evolutionary process has just steered clear of those colors.