Mexican Cavefish Lost Its Eyes To Save Energy, Research Suggests

Posted: Sep 13 2015, 9:06pm CDT | by , in News | Latest Science News


Mexican Cavefish Lost its Eyes to Save Energy, Research Suggests
Mexican Cavefish

Swedish research reveals the reason behind the fish that has no visual system. It's well-developed eyes come at a very high cost.

New research suggests that eyes are developed at the expense of other body organs. A certain body organ is developed at the cost of another organ that is less important in that particular environment.

This is the first study aiming to determine exactly how costly a visual system is. For the study, researchers from Lund University, Sweden examined the Mexican cavefish. The species has lost its eyes due to deterioration. 

Researchers have found that cave-dwelling Mexican morph is totally different from its surface dwelling variant. The surface fish has got larger eyes and more access to food and required nutrients whereas cavefish lives in an environment that is dark and lacks food. Because of the dark environment, the cavefish needs no eyes instead they need food to live.

“Our measurements in the Mexican cavefish show that the visual system requires between 5% and 15% of the animal’s total energy budget, depending on the age of the fish. This is a tremendously high cost! Over evolution, this morph lost both eyes and visual cortex, without a doubt because of unsustainable energy cost of maintaining a sensory system that no longer had any significance.” Damian Moran, one of the researchers said.

Researchers found that Mexican cavefishes required such a large proportion of the total stored energy to maintain their visual system that it had become unaffordable for them. Since they had no use for the eyes, they got rid of them. Those fishes that are dependent on their eyes for survival pay a huge cost for it.

“Any animal that lives in permanent darkness and does not need vision to find food or avoid predators won’t really need their eyes or visual centers in the brain.” Whereas “Animals with large and well-developed eyes, necessary for their survival, pay a huge price for them. As all Animals have strictly limited energy budget, a major investment in visual system only occurs at a cost to another organ systems.”

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Hira Bashir covers daily affairs around the world.




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