I’m surprised that I haven’t gotten around to posting this yet. Here is one of my favorite mantis shrimp videos of all time.
This segment was a bit of humor produced for ‘The Fastest Claw in the West,’ a documentary from 1985 about mantis shrimp. It is narrated by blog-hero David Attenborough, and features stomatopod expert Roy Caldwell. It turns out you can watch the whole thing on Youtube. It’s great fun and very informative. I highly recommend it:
‘The Fastest Claw in the West’: Part 1, Part 2, Part 3
Also, check out Dr. Caldwell’s youtube channel for more great stomatopod videos.
In contrast to the pretty and placid G. playtsoma, today I have a photo and video of one of the meanest mantis shrimps I have encountered. Gonodactylus chiragra occurs in the same intertidal reef flats as G. playtsoma, but its temperament is the polar opposite. It hits hard and often.
You lookin' at me?
Its coloration is a mottled brownish-yellow-green on creme; except for bright orange and yellow accents on the antennae, mouthparts, and walking legs.
Here is a quick video of G. chiragra, whalloping the wall of its aquarium; attempting to hammer my finger (off-screen). It plays at regular speed and then at one-tenth speed (the slow-mo is much more impressive and/or comical, in my opinion).
If you want to know more about the astounding stomatopod strike, check out my previous article: Why Stomatopods are Awesome, I: Super Strength.
This was my first attempt at editing together a video, and I will hopefully have more content like this in the future.
I first saw this species of stomatopod in the field this year. They are really beautiful animals, with subtle but vibrant color accents on their dactyls, antennae, eyes, and on the edges of some of their somites (body segments). This individual is about 72 mm in length, and the species seems to be fairly docile (for stomatopods).
This animal also has very beautiful fluorescent patterns on its body:
G. platysoma; UV-excited fluorescence.
I talked previously about fluorescence in stomatopods here. However, I don’t know if the patterns on G. platysoma are used to amplify any particular signals. These animals live in shallow water and would have less use for fluorescent signal amplification.
Disney Nature has a new IMAX documentary out titled, ‘Oceans‘. A quick survey of the reviews of the film indicates that a mantis shrimp, Odontodactylus scyllarus, is a part of the most memorable sequence of the film. Here is a clip of the mantis shrimp’s scene, (available in 1080p on Youtube). Near the beginning there is a really nice shot of the pseudopupil (the facets of the eye looking directly at the observer).
I, however, have a couple criticisms of this sequence. First off, this was almost definitely shot in an aquarium. Secondly, what is it with IMAX movie makers and repeatedly pushing animals towards stomatopod burrows until they lash out? Similarly to the sequence from ‘Deep Sea 3D’ where an octopus is forced to approach the burrow of a Hemisquilla californiensis, the mantis shrimp in this video shows no interest in predating the crab. He just seems to be trying to get the crab away from his hole. Normally, the crab would surely oblige if it wasn’t for the Disney filmmakers repeatedly pushing it back.
I can’t help but be reminded of Disney’s ‘White Wilderness‘ documentary where the filmmakers pushed lemmings off a cliff into the ocean in order to convince people, incorrectly, that lemmings engaged in suicidal behavior. They are quite a viscous bunch over in the Magic Kingdom.
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.
Mantis shrimp use a variety of visual signals in order to communicate with one another. One set of commonly used signaling structures are the antennal scales; flattened, paddle-like structures derived from the second antennae and set on either side of the mantis shrimp’s head. They have a wide range of motion and can be directed at other mantis shrimp as part of intraspecific threat and mating displays. The antennal scales are often adorned with attention grabbing color and polarization patterns that stand out to other visually adept mantis shrimp.
Attenuation of light in water. Adapted from Levine and MacNichol, 1982
However, the deep ocean is not kind to color contrast. As you move deeper, the absorptive and refractive properties of water attenuate the spectrum of available light. Longer and shorter wavelengths are filtered out until eventually the only available light is blue-green, around 480 nanometers in wavelength (left). Despite this limitation, some deep water mantis shrimp have found a way to preserve their color signals in an essentially monochromatic environment.
Lysiosquillina glabriuscula has bright yellow spots on its antennal scales and the underside of its carapace. This species is found in the shallows as well as at greater depths. It turns out that the yellow spots contain fluorescent materials that are stimulated by blue light and emit yellow light, similar to the yellow reflected light that the spots produce in white lighting. Therefore, these mantis shrimp are able to preserve their yellow spot signals at depths where there is only blue light available.
L. glabriuscula in white light (left) and blue light (right). Blue light is filtered out in the second picture in order to better show the green and yellow fluorescence on the animal. Adapted from Mazel et al., 2004
- Mazel CH, Cronin TW, Caldwell RL, & Marshall NJ (2004). Fluorescent enhancement of signaling in a mantis shrimp. Science (New York, N.Y.), 303 (5654) PMID: 14615546
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.