S3E4: Octopuses

  S3E4: Octopuses!

In today’s episode, The Captivating Creatures of the Deep, octopuses were the main topic of discussion. The octopus has a vast behavior repertoire and various unique characteristics that make them important for research and scientists to study. We wanted to dive into specific aspects of the octopus, including an introduction on the phylogeny of octopuses and a basic overview of how their camouflage works and how these cephalopods reproduce. 

Emilie highlighted the scientific classification of the octopus and what general characteristics they have. Octopuses and their relatives, cuttlefish, and squids, form the class of modern cephalopods. These are known as soft-bodied molluscan invertebrates. For starters, their soft bodies allow them to squeeze through tiny holes and fit in any space. They use their eight arms that are equipped with rows of suckers that are used for probing the environment, catching prey, and much more. Their mantle and siphon (used in breathing) endow them with fast, jet-propelled swimming. When a predator is after them, they can squirt streams of ink to deter them. Their unique chromatophore system generates different skin color patterns which allow them to camouflage to a variety of backgrounds. These are just some of the behaviors that are characteristic of the octopus. 

 Hanlon, R. T., Chiao, C. C. C., Mäthger, L. M., Buresch, K. C., Barbosa, A., Allen, J. J., … Chubb, C. (2011). Rapid adaptive camouflage in cephalopods. Animal Camouflage: Mechanisms and Function, (i), 145–163. https://doi.org/10.1017/CBO9780511852053.009 

Hanlon, R. T., Chiao, C. C. C., Mäthger, L. M., Buresch, K. C., Barbosa, A., Allen, J. J., … Chubb, C. (2011). Rapid adaptive camouflage in cephalopods. Animal Camouflage: Mechanisms and Function, (i), 145–163. https://doi.org/10.1017/CBO9780511852053.009 

Jordan then discussed the three different types of camouflage that octopuses can display; disruptive, mottle, and uniform (see above figure). A uniform pattern is one that has little to no contrast, usually being one color with a set level of brightness. A mottle pattern is one that has a small to moderate scale light and dark contrast, similar to that of gravel. The final type of camouflage, disruptive, is the most extreme of the three and is described as being a camouflage that has a large scale light and dark contrast.  The next aspect of octopus camouflage that was discussed was how octopuses base their camouflage off specific structures within their visual field instead of trying to match their entire visual field. Emilie provided a great example of this process with the octopus camouflaging itself in the algae on a rock (see figure below). Here the octopus chooses the algae specifically to match with instead of trying to match the entire rock. 

Hanlon, R. (2007). Cephalopod dynamic camouflage. Current Biology, 17(11), 400–404. https://doi.org/10.1016/j.cub.2007.03.034

After some of the general characteristics of octopus camouflage, RNA editing and signaling between octopuses were discussed. RNA editing is a post-transcriptional process that allows for the diversification of the proteins that can be expressed by an organism.Recent studies show that cephalopods have an extremely high number of RNA editing sites compared to humans and other mammals. Some of the advantages of altering their genetic information through RNA editing instead of hardwire changes in their DNA are increased phenotypic flexibility, innate immunity, and RNA level changes can better augment genetic diversity.

The last topic that was discussed in terms of camouflage was how octopuses use their color-changing ability in more ways than just hiding from predators.  In one particular study, it was found that octopuses will change color and size during interactions and that the displays predict the outcomes of the interaction. A raised mantle and darker colors are associated with aggression and when the colors of two octopuses are similar a fight is more likely.

 https://faquatics.tumblr.com/post/56260031936/the-penis-thats-as-long-as-an-arm-the-octopus.

Gabe then discussed the general ways that octopuses reproduce with males using their hectocotylus arm to insert it into the female to reproduce. Also how there are cannibalistic tendencies in certain species of octopuses. Then he covered how there are sexual preferences with octopuses and how females prefer males that have already mated with another female. With many observations by scientists showing females chasing down smaller males to cannibalize them. Certain male octopuses are in such of a risk of female predation that they were observed putting more risk of being out in the open for predation of other predators. Another thing that was discussed was the intelligence of these octopuses and the tricks females play on males. 

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Hanlon, R. T., Chiao, C. C. C., Mäthger, L. M., Buresch, K. C., Barbosa, A., Allen, J. J.,

Chubb, C. (2011). Rapid adaptive camouflage in cephalopods. Animal Camouflage: Mechanisms and Function, (i), 145–163. https://doi.org/10.1017/CBO9780511852053.009 

Josef, N., Amodio, P., Fiorito, G., & Shashar, N. (2012). Camouflaging in a complex 

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 Scheel, D., Godfrey-Smith, P., & Lawrence, M. (2016). Signal use by octopuses in

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https://mp3bearz.online/genuine-my-pony

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