Blind Cave Spiders Show the Ability to Sense Light
A group of environmental scientists from Hubei University, China, along with a researcher from the University of Iceland, discovered that blind spiders residing in deep caves in China can still detect and respond to light. Their study, published in Science Advances, involved testing two groups of spiders living in cave systems in southwestern China.
Previous studies have indicated that creatures residing in light-deprived caves tend to lose their vision over time, with some species even evolving to lose their eyes entirely. Despite this, some cave-dwelling creatures, after losing their eyes, can still sense light, often using this ability to avoid it. In a recent study, researchers explored whether this phenomenon occurs in the Leptonetela genus, which includes numerous species of tiny, blind, or nearly blind spiders living in dark caves.
Eye Adaptations in Leptonetela Spiders
The researchers observed that certain Leptonetela species, found near cave entrances, retained six eyes instead of the typical eight found in non-cave-dwelling counterparts. These eyes are usually employed for prey detection. On the other hand, deeper-dwelling Leptonetela species lost their vision, with some even losing their eyes entirely.
To investigate how both groups respond to light, the researchers collected 10 specimens from each category and conducted laboratory experiments. The spiders were placed in containers divided into light and dark sections, allowing them to move freely between the two halves.
Light Sensing in Leptonetela Spiders
In their experiments, the researchers observed that spiders from both groups consistently preferred the dark side of the enclosure. This behavior, they propose, indicates that all spiders, regardless of their eye status, possess the ability to sense light. Additionally, the researchers identified the presence of genes associated with light responsiveness in all the spiders.
The study’s conclusion suggests that the spiders retain their light-sensing ability due to the necessity of avoiding the dry conditions near the cave entrance. Tests further revealed that spiders completely lacking vision could not survive in such a dry environment.
Read the original article on: Phys Org
