Blind cavefish enhanced feeding behavior to the scent and sound stimuli.

What is it about?

The cave environment is harsh due to limited food and permanent darkness. Cave-adapted animals, including salamanders, insects, and fishes, reduce their eyes to save energy. Without visual inputs, how do these animals find food? We tested the visual, auditory, tactile, and olfactory stimuli to address how blind cavefish altered their sensory criteria compared with their surface-dwelling sighted population.

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Photo by Timo Volz on Unsplash

Photo by Timo Volz on Unsplash

Why is it important?

The manner how an animal weighs on each of multiple sensory inputs to navigate itself is called "sensory modality." Animals change their sensory modality according to available stimuli from the environment. Blind cavefish are known to increase their behavior responses to non-visual stimuli such as a vibration stimulus (through lateral line) and amino acid odorant stimuli (through olfactory epithelium). However, how cavefish weigh on these sensory inputs was not known. As we found, cavefish responded more to the sole chemical (food scent) or mechanical stimulus (plastic beads) than surface fish, suggesting that cavefish shifted to 'rely' on sole stimulus while surface fish may need multiple sensory inputs to judge food. In addition, cave and surface fish did not use the scent gradient to locate the scent source but used it as a cue of food's existence in the environment. This food-locating strategy now makes sense to find food in a lean and water-flowing environment.

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