Video depicts how chromatophores embedded in the skin of octopus expand or contact to enhance camouflaging. Video credit-https://www.youtube.com/watch?v=OWbanx8U4cM
Octopus bimaculoide , my species of interest is classified further as member of subclass Coleoidea and order Octopoda. There are various distinguishing features of this organism but I am choosing to headline their chromatophores embedded in their skin for today.
O. bimaculoide, a coleoid cephalopods evade predators by changing the appearance, marking and texture of their skin. Camouflage in cephalopods depend on central nervous system, eyes and skin (chromatophores). (2)
The morphology of chromatophores in coleoid cephalopods is unique compared to other members of mollucsa as well as different phylums such as Arthropoda.(1)
Chromatophores in coleoid cephalopods have evolved into small, elastic pigment granules filled cells with surrounding muscle cells. When the muscle cells contracted, they stretch the cells into pigmented sheet and when the muscles relax, the chromatophore shrinks back to small circles. This contraction and relaxation changes their appearance faster than other animal.(Fig A and B) (1,3)
Cephalopods utilize their well-developed eyes to gather information about the brightness, contrast and edges of light in their surroundings. Information gathered highly affects changes in the color, texture and markings of their skin. This also serves as a means of communication.
New studies has determined that the skin of O. bimaculoides can sense light independent of the central nervous system.It’s ability to sense light is not as detailed but can sense increases and brightness.(3)
Chromatophores in skin of O. bimaculoides reaction when illuminated. Photos from infrared video of adult O. bimaculoides funnel skin light-activated chromatophore expansion. (A) Contracted state of chromatophores after 3 s of exposure to bright white light. (B) Expanded chromatophores after 6 s of exposure to bright white light. (C) Chromatophores in skin of O. bimaculoides reaction when illuminated. Scale bars: 100 μm.
Joke of the day
How do you make an octopus laugh? You give it ten-tickles.
References
1.Hickman et al (17) Integrated principle of zoology, McGraw-Hill Education chapter 29 page 642. Viewed online on 3/1/2018 at https://newconnect.mheducation.com/flow/connect.html
2.Messenger, J. B. (2001). Cephalopod chromatophores: neurobiology and natural history. Biol. Rev. Camb. Philos. Soc. 76, 473-528. doi:10.1017/S1464793101005772. Viewed online on 3/1/2018 at http://onlinelibrary.wiley.com.ezproxy.gsu.edu/doi/10.1017/S1464793101005772/abstract;jsessionid=EE9341B5C9616D73519F116B64E411F1.f04t02
3.Ramirez M. Desmond, Oakley Todd (2015) Understanding the dermal light sense in the context of integrative photoreceptor cell biology. Journal of Experimental Biology 2015, 218: 1513-1520; doi: 10.1242/jeb.110908. Viewed online on 3/1/2018 at https://labs.eemb.ucsb.edu/oakley/todd/publications/107