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.
I will be presenting a talk about my research tomorrow at SICB in Charleston. If you are at the meeting and want to see what I’ve been doing instead of updating this blog, come by Room 1 at 1:20. I will also be a the Crustacean Society social tomorrow evening.
Come say hello!
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.
Who can tell me what this classic figure is demonstrating? This is a lead in to a much more involved post that I am working on for next week.
I’ve always westled over a good way to share all the interesting science articles I come across around the web. In the past, I would horde bookmarks and put together “arthropod roundup” posts from time to time. However, that became a bit of a chore and I constantly fell hopelessly behind. Twitter seems like the obvious answer to this, but it has always felt a little chaotic to me; I still haven’t really gotten into any sort of groove with it. Facebook is also an alternative, but I’ve segregated that area of the web for family, and non-science inclined friends/nonsense.
Recently, I’ve settled on Google Plus as a superior (to me) science communication alternative. I really like the sharing interface and the nice emphasis the system puts on photographs and images. I’ve added my public Google Plus stream to the left sidebar of this page. This is where you will find lots of additional sciencey goodness, while Arthropoda will be reserved for full-fledged articles from me. Feel free to keep an eye on my feed, or join me on google plus, which seems to be growing great, professional communities of science enthusiasts and photographers.
I am going to start building a collection of posts about specific species of mantis shrimp; including photos, general information, and the research that they have been a part of. I will make an index for these posts and update them periodically with additional information. First up is the mantis shrimp that I spent most of my summer with:
Haptosquilla trispinosa
Haptosquilla trispinosa
Stomatopoda (Order)
Gonodactyloidea (Superfamily)
Protosquillidae (Family)
Adult size: Up to 44 millimeters
Distribution: Northeast Australia,
East Indonesia
General information and care: Roy’s List
H. trispinosa is very common at our field site, living in small burrows in coral rubble. We typically collect them from intertidal habitats, but they can be found deeper as well. Though they appear a drab tan or cream color at first glance, they actually have some beautiful color accents up close. These include orange antennae, blue spots on the back, and beautiful blue maxilliped mouthparts that are held front and center, just below the head.
A clearer, slightly enhanced view of the blue maxillipeds.
Much of the recent research on this mantis shrimp has focused on these blue maxillipeds. The light coming from them is polarized and they are almost certainty used for visual communication. Also, their wide habitat depth distribution has made them ideal for studying the adaptation of photoreceptors to variable light environments through tuning of light filters in the eyes. Social interactions and chemosensory have also been studied in H. trispinosa.
I predominately use these animals for behavioral learned choice experiments, in which I train them to associate a food reward with a particular light stimulus. Thus we can ascertain the functional limits of their visual systems. These experiments exploit the intrinsic predatory behavior of this mantis shrimp. For the majority of the day they will sit in the entrance to their burrow, scanning the water column for a potential snack. When something delectable drifts by, they lunge out, snare their target and dive back into their burrow. This behavior, called “hawking”, gives us a clear response when we present them with a stimulus choice.
Here is the best video I managed to get fo this behavior from an animal in one of my artificial burrows in an aquarium:
Selected research about H. trispinosa:
Epomis beetle larvae eating a toad.
You can read more and watch some videos at Wired, or check out the original research paper at PloS ONE.
I can’t find any information about these beetles being found in Australia, so hopefully Plugg is safe… gulp
Check out this great graphic detailing important steps in the evolution of a visual system, created by Voltier Creative:
I think it does a really good job of presenting the classical example of eye evolution by gradual changes, each stage of which is observable today in nature. The only thing I take any exception to is the “most evolved” statement regarding the mantis shrimp eye. Truth be told, many biologists use the same language when talking about any especially complex biological system. However, that doesn’t really sit right with me. Everything has been evolving for exactly the same amount of time. Nothing is more or less evolved, and complexity does not necessarily mean that more evolutionary “work” has gone into it. Modern animals with less complex eyes, like Euglena, are not less evolved; their visual system is continuously evolutionarily tuned to be as close to ideal for its lifestyle as possible.
A better way to put it would be something along the lines of, “mantis shrimp have the most diverse photoreceptor array of any animal.” Furthermore, mantis shrimp don’t really represent sight perfection either. Because of damning resolution limitations inherent of compound eyes, almost any animal with a camera eye has much better spatial resolution. Even through they have the second best spatial resolution among animals with compound eyes (behind dragonflies), mantis shrimp are still well below humans in that regard.
My stint in Australia has been extended by two weeks to finish up some behavioral work. Since I’ve finally got the shrimp circus preforming, it would be a waste to pack it up with so many experiments left to do.
In the mean time, here is a little pop quiz:
Who can tell me what this is?
???
Here is a set of adorable (non stomatopod) animals that I have come across here at Lizard Island. I know, only two are arthropods, and I don’t usually like to post about cephalopods that aren’t being bludgeoned to death by mantis shrimp, but these are still really cute/awesome animals.
A baby blenny that rode our salt water system into the aquaria facility. Luckily he dropped into a cleaner wrasse tank, and not one of my mantis shrimp tanks.
A swimming isopod, caught at night. Many pelagic nocturnal creatures are attracted to light, so we bring them in with dive lights and scoop then up with fine mesh nets.
One of the thousands of small skinks around the station.
A baby cephalopod caught during a night dive. It is about a centimeter in size a is disgustingly adorable. Squeee! Check out the chromatophores and iridophores.
Finally, an ant that I found chugging the ink out of my fountain pen for over an hour last night. Its abdomen is usually brown, but has turned dark black as it filled with ink. Eventually she just wandered off, to a fate unknown. You may also notice some raw SCIENCE! in the background.
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