I haven’t had much time to write this week on account of wanting to graduate someday. Here is one of the animals that I’m working on at the moment.
N. bredini is the easiest mantis shrimp to find on the east coast since they commonly hitch-hike on reef rubble, cultured in Florida for the aquarium trade. The photo above shows the ‘smasher’ raptorial appendage nicely, as well as the black pseudo-pupil (the facets of the eye that are directly facing the camera). These guys come in a bunch of different color morphs including the rusty color above, green, and grey mottled.
I’m trying to improve my photography skills, but the old Olympus C-5050 I’m using isn’t cutting it any more. It’s no fun trying to manually focus on a moving critter using a 1.8″ 110,000-pixel screen.
Edit: Correction, this animal is actually N. wennerae. This species is physically indistinguishable from N. bredini. The only reliable determinant other than genetics is habitat depth.
I haven’t been able to post any hard science this week since I’ve been working on a presentation for my department’s annual symposium. So far, this is the largest audience I have presented my work to.
I thought I might quickly share one of my slides from that presentation as a preview for a much larger future post about the ridiculously complicated mantis shrimp visual system.
Click to embiggen. Stomatopod Photo: Roy Caldwell
This is a comparison of photoreceptor classes in human and mantis shrimp retinas. Each photoreceptor class has a distinct wavelength sensitivity curve. On the human plot, you can see our three cone photoreceptor classes; blue, green, and red. These receptors cover the electromagnetic light spectrum between 400 nm (violet) and 700 nm (red). Our brains are able to process relative stimulation between the three cone photoreceptor classes, allowing us to differentiate many colors.
Mantis Shrimp don’t have the advantage of a large brain for downstream processing, so they take another approach to seeing many colors: They have 16 distinct photoreceptor classes, packed via optical filtering into tight slivers of the spectrum. Of these, five classes are sensitive to UV light, below our visual range (these are the receptor classes that I am attempting to characterize). In addition, not shown in this slide, mantis shrimp can discriminate linearly and circularly polarized light.
Stay tuned for an in depth mantis shrimp vision post at some point.