Ophiopsila aranea :
Organisms have adapted to use Bioluminescence in many different ways to defend against predation within the deep-sea; where visible light from the sun is near non-existent. An example of an organism that utilities a lot of these methods is Ophiopsila aranea a member of the Brittle Star or Ophiuroids class, in this class at least 77 species are known to be luminescent. O. aranea is able to utilize its bioluminescent adaptation, with regards to defence against predation, in different methods;
Organisms have adapted to use Bioluminescence in many different ways to defend against predation within the deep-sea; where visible light from the sun is near non-existent. An example of an organism that utilities a lot of these methods is Ophiopsila aranea a member of the Brittle Star or Ophiuroids class, in this class at least 77 species are known to be luminescent. O. aranea is able to utilize its bioluminescent adaptation, with regards to defence against predation, in different methods;
Sacrificial Lure:
As you can see in the image on the right the luminescent capabilities of O. aranea is spread homogeneously along their arms. This organism is able to, under sufficient stress, undergo autotomy of distal parts of their arms when attacked. This sacrificial behaviour is used to distract a predator if other behaviors such as the startle and burglar effects fail to be effective, but surely this is detrimental to the organism? Well, O. aranea is also able to regenerate the sections of their arms which may undergo autotomy, although this process consumes a large amount of energy, it is still implemented by a range of Ophiuroids. The process of regeneration in a similar species of brittle fish, Amphiura filiformis, includes expression of 694 genes and the utilization of 194 proteins. There is another impressive feature regarding this behavioural adaptation. Not only can O. aranea undergo self autotomy they can also ensure that the detached appendage continues to illuminate, in fact research shows that the amount of light emitted by this appendage increases in an attempt to distract a predator. It is not clear how O. aranea enables the detached appendage to emit light however, it may be that the organism utilizes Photoproteins and releases a large amount of activating ions just before the section undergoes autotomy. |
Startle Effect:
This is the use of bioluminescence to deter predators, O. aranea emits a large amount of light that may directly startle a predator, such as Carcinus maenas, allowing the organism to evade predation; utilizing the locomotion function of the organism’s arms. It is suggested that within other organisms this behaviour can be stimulated by the change in pressure caused by the presence of a large, often inanimate, objects such as a boat or debris, however this behaviour can also be induced by the presence of a larger predator, it is believed that these facts are the same for O. aranea. A similar behaviour to the Startle effect is called the “burglar alarm effect”. In relation to the startle effect, light is emitted by O.aranea when a predator may be present however; the purpose of this light differs. The purpose of this behaviour is to illuminate a predator, for example C. maenas, thus hopefully attracting a secondary predator, such as Cancer productus. This way the primary predator becomes prey to the secondary predator allowing O.aranea, in principle, to escape unharmed. |