Man is but a worm

Man is But a WormI’ve had a lot of life changes since my last activity her. I’ve gotten married, defended my PhD, and moved to Lund, Sweden to do my postdoctoral research with Dan-Eric Nilsson. I’m changing gears a little bit from my mantis shrimp, but I’m staying in vision research. I will now be working on some slightly less ridiculously elaborate eyes in annelid worms and various other phyla. Instead of looking at vision in one of its most complex and convoluted forms, I am going to be exploring some of nature’s simplest eyes in order to learn more about the origins of vision and visually guided behaviors. I still love my crunchy arthropods though, so hopefully this space can provided a nice outlet for me to talk about something other than my specific research – which is what burnt me out of blogging previously. Stay Tuned!

I guess this means my study animal is mainstream now?

Mantis shrimp have always been the coolest animal in the universe (don’t bother arguing this point), but now everyone finally seems to be aware of this fact.

All it took was being feature by one of my favorite webcomics, The Oatmeal.

This is a great piece of pop-science art. Sure it is rife with misconceptions, but it has also driven interest in these animals through the roof. Google search traffic for “mantis shrimp” is at an all time high, and traffic to my blog has spiked quite a bit as a result. Hopefully all this interest will lead some people to learn more about the Worlds Best Animal (TM).

Thanks Oatmeal.

Here are a couple of my favorite bits from the comic:

This is poetry.

This is poetry.

Sure, we have no idea if this is true, but it's a fun analogy.

Sure, we have no idea if this is true, but it’s a fun analogy.

I now have a response for when my aging relatives ask me what the practical application of my research is.

I now have a response for when my aging relatives ask me what the practical application of my research is.

Some shots from the field 2012: Critters

Here is a collection of critter shots from Lizard Island last field season.

Mantis shrimp larva, Lysiosquillina maculata. This penultimate larva is about ready to molt into its post-larval juvenile form, and is starting to look a bit like a mantis shrimp. The adult eyes are developing alongside the degenerating larval retina, and the raptorial appendages are visible. Like the majority of mantis shrimp larvae we catch, this individual was lured in with a dive light and scooped up with a fine net.

Another species of mantis shrimp larva, Alima pacifica. This animal is the largest mantis shrimp larva I have seen.

A juvenile Zebra Lionfish, Dendrochirus zebra.

I wonder why they call it Lizard Island? The island is in fact named after the omnipresent monitor lizards, Varanus gouldii. It was named so by Captain Cook in 1770, who stopped at the island in order to get a better view of the outer barrier and chart his course out. The summit of Lizard Island is called Cook’s Look.

Some sort of bumblebee shrimp. This adorable female turned out to be carrying a lot of eggs and soon hatched out a number of larvae.

Frilly slug

Happy slug

Some shots from the field 2012: Places

Here is a collection of photos from my most recent field trip to Lizard Island on the Great Barrier Reef last summer. I neglected to post them at the time since I was on a bit of a hiatus. As things look right now, I will have one last trip to this special place this coming summer to wrap things up before my post-doc. It’s going to be a sad summer when I can no longer make my annual visit this biological wonderland for my research.

This post will show off some of the locales around the reef, and a subsequent post will show some critters up close.

Some pretty coral on the outer barrier. The outer barrier is about 10 miles from the Lizard Island reef platform, which is shielded from the Coral Sea by the outer barrier.

A couple of my colleagues diving amongst the coral heads on the outer barrier, at a beautiful spot called No Name Reef.

This shot gives you some idea of the density of fish and coral on the outer barrier.

One of the couple small mangroves at low tide.

An unusual view of Lizard Island, taken from Palfrey Island, a member of the Lizard Island Group. Unlike Lizard, which has an airstrip, resort, research station, pub and campground. Palfrey is undeveloped, save for a lighthouse with a heli-pad. This includes no trails, so the climb to the summit was extremely treacherous, over granite bolders obscured by chest high grass. By the time I made it down to my boat I was fairly mangled from the climb, as well as from a painfully comical wipeout when I tried to take a timed photo of this view with myself on the bolder on the bottom right.

The Lizard’s Neck. In the previous photo, you can see a point on the far right side of Lizard Island. That point vaguely resembles a lizards neck and head. This photo is taken from the head, looking back over the narrow neck. To the left is the central lagoon, and to the right is Coconut Reef. At extreme low tides, this reef comes completely out of the water, making it an ideal hunting ground for mantis shrimp roaming in the shallows. This is the worlds greatest tide pool, and collecting here is my favorite part of every field season. Also, the neck is usually covered in long grass, but there had recently been controlled burns in this area, making it a bit more barren than usual.

A sunset at a very low tide. I need to make a coffe table book about Lizard Island sunsets. I must have photos of over a hundred unique sunsets, all taken from this exact position.

Peacock

It’s been a while, but I’ve gotten the itch to get back to writing here. Lets jump back in with a bang!

Last month. I finally got a hold of the species of mantis shrimp that many would consider the crown jewel of Stomatopoda – Odontodactylus scyllarus.

Odonotodactylus scyllarus. You can see her smashing appendage on the bottom left.

Personally I think O. scyllarus is a little too gaudy, completely without subtlety of appearance or demeanor; more of a painted tramp in my estimation. This particular animal is a female, as evidenced by the rusty carapace color. Males tend to be more green-ish.

This species is commonly referred to as a ‘Peacock Mantis Shrimp’ for obvious reasons; they are a riot of color. In addition to the color we can see, they also sport an impressive array of polarized signals around their bodies. They can make good use of these visual cues with sixteen spectral classes of photoreceptors and have been trained to discriminate color, linearly polarized light, and circularly polarized light.

O. scyllarus is also one of the largest true smashers, reaching over 7 inces in length. When you hear about mantis shrimp that can break aquarium glass, they are likely referring to this genus. They have been shown to generate strike forces with their calcified dactly hammers of up to 1500 Newtons, and can lash out at speeds of 20 meters per second.

O. scyllarus hails from the Indo-Pacific waters, and are found in slightly deeper waters, generally between 10 and 30 meters.

Brushing off the attenules with modified scrubbers on the first maxillipeds.

Hmmmm, I wonder why they are called ‘Peacocks’?

Finally, below is a video showing off the wild eye movements that this animal makes.

You’ll notice that each eye pans and rotates on multiple axes independently. They can do this and retain depth perception because each eye has independent range-finding capabilities. In order for optical range-finding you need at least two spatially separated visual fields observing the same point. We can use our two eyes together for binocular depth perception. Mantis shrimp on the other hand, have trinocular depth perception in each eye.

This is evidenced by looking at the pseudopupils. The pseudopupils are the areas of dark facets looking directly at the camera that seem to move around the compound eye of the mantis shrimp. You’ll notice that when an eye is looking directly at the camera, there are three spatially separated pseudopupils. Thus, by having three separate parts of each eye looking at the same point in space, mantis shrimp possess the capability for trinocular depth perception.

For information about aquarium care of this popular pet species, check out Roy Caldwell’s page.

References:

  • Marshall, J. et al., 1999. Behavioural evidence for polarisation vision in stomatopods reveals a potential channel for communication. Current Biology, 9(14), pp.755–758.
  • Marshall, N.J., Jones, J.P. & Cronin, T.W., 1996. Behavioural evidence for colour vision in stomatopod crustaceans. Journal of Comparative Physiology A, 179(4).
  • Chiou, T.-H. et al., 2008. Circular Polarization Vision in a Stomatopod Crustacean. Current Biology, 18(6), pp.429–434.
  • Patek, S.N., Korff, W.L. & Caldwell, R.L., 2004. Biomechanics: deadly strike mechanism of a mantis shrimp. Nature, 428(6985), pp.819–820.

“Go it Charlie”

Happy (slightly belated) Darwin Day! To celebrate, here is a cartoon of Darwin I first saw when visiting Down House last summer.

It was drawn by Darwin’s friend and classmate at Cambridge, Albert Way, in 1832. I think the drawing quite nicely speaks to Darwin’s enthusiasm for natural history, and especially beetle collecting, well before his historic voyage and academic achievements later in life.

Spectrum of Life

Here’s my attempt at creating a blog meme. Arrange a selection of your nature photos according to their color in the light spectrum.

Unfortunately, I don’t have a picture of anything purple, so I left that out. Also, feel free to be a bit subtler than I was. The arrangement can also tell some sort of story; mine unintentionally appears to be about a bunch of hungry invertebrates surrounding a cute, hapless chordate. Take what you will about my psyche from that.

If anyone wants to do this, please add your attempt to the comments.

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