mantis changing color

[Reefgoddess2]

I have a two inch mantis I managed to capture from my main tank in December 2003. The stomapod expert on here thought it was a G. smithii based on my photo. At that time it was basically brown with some colorful flecks of color. It recently moulted and it is now a farly bright green for the base body color! Is color changing common in mantis and what casuses this? Just curious. BTW he is not exposed to any special lighting - he is in one of those 2 gal Explorer tanks without a light - he just gets the ambient room lighting. I am feeding him frozen brine shrimp and squid soaked in Selcon.

 

[Hwarang]

Good morning!

Mantids change color with each molt, in response to their lighting conditions. Even though your lighting may not be supercharged, it's got different parameters than sunlight filtering down to the natural reefs. I've heard 500,000 people post that the very bright colors our mantids get come from the intensity and spectrum of aquarium lighting - but I've never seen a technical explanation of what's going on. I'd suspect, since aquariums feature a range of lighting with a wide range of output, that it's primarily intensity that causes the color shift.

I just checked some links but none gave the answer I was looking for. Perhaps our resident expert can give us some in-depth information.

-B

 

[Gonodactylus]

Color change is influenced by many factors. The most important is species. Some species never change color. Others such as Neogonodactylus wennerae and Pseudosquilla ciliata are highly variable and change dramatically when they shift from one habitat to another. Major color changes only occur when an animal molts. You can get minor shifts in color due to chromatophore changes, but in most species these only are reflected in a darkening or lightening of the body. Developing ovaries and changes in the hepatopancreous can also cause a change in appearence. However, the dramatic changes in color involve shifts in the pattern and color of pigments deposited in the cuticle and only occur when the new cuticle is laid down. They are then revealed when the old cuticle is shead.

As far as we know, color changes are controlled through visual pathways. There is no evidence that light falling on any structure other than the compound eyes can influence the color of the cuticle. There is evidence in a few species such as P. ciliata and N. oerstedii that not only the color, but also pattern of light reaching the eyes can control body color and pattern.

In most cases, intensity is not as important as spectral composition and the surrounding habitat although there is certainly an interaction between intensity and spectral characteristics with depth. Diet can also play a role. In some species there are also ontogenetic changes.

G. smithii is primarily a low intertidal species that is exposed to broad spectrum lighting and a great diversity of reflected colors on the reef. In the field, most animals have a background color of mottled green or olive, However, a few G. smithii settle out at depths greater than 15 m where most downwelling ight is blue. These individuals are often maroon or brownish. Placed in broad spectrum illumination, they usually turn green after one or two molts

Roy.

 

[Hwarang]

*soaks it up*

Thanks!


*mills it about*

Hmm what about the fact that a huge number of wennerae turn bright green (perhaps you'd care to debate or correct my impression of this "fact")? The fact that so many turn bright green under such a range of home aquarium conditions suggests it has little to do with the parameters of the light, no? The only parameter that would be the same for all would be (relatively, compared to the ocean) intensity. So, from what you said, I would infer that after biological instructions, intensity - not specturm etc - would be the driving force.

This is all just from observation though, and since we know that correlation != causation, I could be hypothesizing out of my rear end.

-Me

 

[Gonodactylus]

The N. wennerae that are appearing in aquaria around the country are mostly from cultured LR farmed at depth. This same species occurs into the intertidal where they are usually green. In shallow water, there is broad spectrum lighting from the uv to far red. This is also true in the home aquarium. While the type of lighting used, if any, may vary, it is still broad spectrum with uv and red tails of the spectrum maintained. Sure, there may be strong peaks at particular wavelengths, but there will also be considerable ambient lighting in addition to the halides or flourescent lights. Very quickly as you go down in the water column, all but blue light in the 470 nm range drops out. We did experiments with several species of stomatopods looking at color change of filters in the eye and found that it was the narrowing of the spectrum to blue that cause the shift. Neutral density controls using dim, broad spectral lighting did not change from the shallow water coloration. There is no reason not to think that cuticle pigments are responding the same way, particularly when our green N. wennerae kept in dim, but broad spectrum light stay green. Obviously there is a lot of research that can be done here. We don't know if it is the ratio of photons at different wavelengths or the absolute number that is important.

Roy

 

[Hwarang]

Fascinating!

 

[goblinsharkman]

My N. wennerae was turning green, then he somehow lost one of his smashers (i have no idea) and has been hiding all week, now hes bright red again