Tripedalia Cystophora Essay

What is the role and purpose of the many eyes found on the box jellyfish Tripedalia cystophora?

Introduction:

The box jellyfish Tripedalia cystophora is a small jellyfish that can be at least 1cm long. Its bell is shaped somewhat like a square, which give it the name “box” jellyfish. Each of the four bottom corners of the bell have three tentacles. Even though it is in the same family as the sea wasp, T. cystophora is harmless. This jellyfish has been observed living in mangrove swamps where it stays in the light near the surface and feeds on copepods like Dioithona oculata. T. cystophora is diurnal, so it is actively feeding and moving about during the day, and at night, it rests on the muddy floor of the mangrove swamps.

The taxonomy

for species T. cystophora is the Domain Eukarya, Kingdom Animalia, Phylum Cnidaria, Class Cubozoa, Order Cubomedusae, Family Carybdeidae, and Genus Tripedalia.
Unlike other jellyfish, the box jellyfish has 24 eyes where each one has a specific purpose that helps it survive in the mangrove swamps. There are four different types of eyes, which includes parts like lenses, retinas, and corneas. These four types allow T. cystophora to move around their environment in response to changes and movement of shadows and solid objects. They also have a special eye which is always looking up through the surface of the water so that they can see what’s above them.

Source I:
Abiahy B, Alder V, Angel M, Bernstein R, Binet D, Boltovskoy D, Bouillon J, Bradford J, Casanova JP, Cornelius P, et al. Zooplankton of the south atlantic ocean. Marine Species Identification Portal [internet].
http://species-identification.org/species.php?species_group=zsao&menuentry=soorten&id=2412&tab=classificatie
This source is a website that is used to identify species of organisms that live in the ocean. The website has many authors who each specialize in a certain type of taxon of ocean creatures. For the section that includes the species Tripedalia cystophora, the website lists information including a description of the organism, its classification, and images of what the creature looks like. This site included complete taxonomic classification information that started at kingdom and went all the way to the species. The description of the jellyfish included many scientific terms and names that I did not know. These words described the look of the jellyfish, its structure, and what the purposes are of each structure or part. The website doesn’t mention much about T. cystophora’s eyes, and focuses more on its biological structure and how it looks.
From this source, I learned about the entire taxonomic classification of the particular species of box jellyfish. I also learned that it is 1cm in diameter and that it has three tentacles on the bottom of each of the four corners that make up its bell. This website also taught me about the structure of its internal organs, such as the stomach and gonads. I also learned about important structures like the nematocyst warts which act as “stingers”. I also learned that the type of larva that the jellyfish produces is called “planula” which have flagella so they can swim freely. Not much information was stated about the eyes of T. cystophora, so this site didn’t help with answering the question about the purpose of the eyes, but it did answer my personal questions about some general information of the species of jellyfish.
I believe that this is a credible source because of how thorough the information is. I also believe that it is credible because on their website, it lists who all of the authors are and what organizations or groups that they work with. The website also states how they used something called “Linnaeus II taxonomic data management package” to put together all of the information that their scientists, researchers, and taxonomists gathered.

Source 2:
Mirsky S. 2011. Box jellyfish eyes aim at the trees. [Internet podcast] Scientific American
http://www.scientificamerican.com/podcast/episode/box-jellyfish-eyes-aim-at-the-trees-11-04-29/
The source from the Marine Species Identification Portal helped me figure out the name and what exactly the species was that I chose. After I knew the basic information, I began looking for sites with information that would help me answer the question that I had about the 24 eyes. I found this source, which is a podcast that was posted on the website of Scientific American. I had searched on the website for the box jellyfish eyes, but I mostly got articles about the sea wasp, but eventually, I found this podcast. The narrator of the short podcast talked about the basic information of the jellyfish eyes and talked more specifically about the eyes that faced upwards towards the surface.
From this podcast, I learned that the jellyfish have 24 eyes that are split up into four types. I also learned more about where the jellies live and how there are four eyes that face upwards towards the canopy of the mangrove forest. By facing in this direction, the jellies are able to move around to ideal spots where their food would be. I also learned, and found it interesting, how the “box jellies have different eye types responsible for informing different behaviors, with no brains”.
I believe that this source is credible because it is a magazine and website that is dedicated to science. Also, the podcast itself was unbiased and factual. The narrator also listed a source from the journal, Current Biology, and a link to the article, which I ended up using as my next source.

Source 3:
Garm A, Oskarsson M, Nilsson DE. 2001. Box jellyfish use terrestrial visual cues for navigation. [internet] Current Biology 21(9):798-803.
http://www.sciencedirect.com/science/article/pii/S0960982211003587
From the information given in the podcast from Scientific American, I was able to discover this peer-reviewed article that discusses research information about the eyes of the box jellyfish.

The article talks about how the group of researchers wanted to figure out the purpose of the eyes, so they decided to look at “the upper lens eye” of the species Tripedalia cystophora. The researchers performed several experiments where they looked at the behaviors of the jelly fish, how the four eyes functioned, how the jellies reacted when they were moved to a different location, and how the eyes were oriented. For the tests on behavior, the scientists tested 15 jellies in three separate groups in different locations in a lagoon. “Five medusae were collected and tested on the northern shore on the lagoon, five were collected and tested on the southern shore, and five were collected on the northern shore but tested on the southern shore”. They put the jellies in tanks and moved them farther and farther away from the shores to see how they would react to being moved out from under the mangrove canopy. Through this experiment and the others, the scientists were able to conclude that “visual detection of the mangrove canopy by the upper lens is the only plausible explanation for the behavioral results”. The behavioral results were that T. cystophora would begin to swim faster and towards the trees as they were moved away from

them.
From this article, I learned a lot about the four eyes that look up and how they help T. cystophora to know where they are. It was interesting to learn that they would stop eating if they were moved too far away and that they would try to get back to their original locations. I learned that they jellyfish prefer to be close to the shore and under the tree and that they will move around by looking at the layout of the shore. I also learned that the eye that looks up is always looking up no matter what direction the jellyfish is swimming.
This is a credible source because the place of where each author works is listed, and each are some sort of science department at a university. Also, the article was published in a science journal, and the article cites all of the resources that they used for their experiments and research. The article is without bias and is very factual, and includes statistical data from their experiments. The article was published four years ago, so it is recent. Also, the article does have some large science words, but it also includes simple explanations that make it easy for almost anyone to read and understand.

Source 4:
Garm A, Bielecki J, Petie R, Nilsson DE. 2012. Opposite patterns of diurnal activity in the box jellyfish Tripedalia cystophora and Copula sivickisi. [Internet] The Biological Bulletin 222:35-45.
http://www.biolbull.org/content/222/1/35.full
After I read the article about the four surface facing eyes, I decided to look for more articles about the jellyfish eyes. I found this one, which has some of the same authors as the last. In this article, they talked about two different species of the box jellyfish and their diurnal behaviors.