Most spiders have evolved while being exposed to the sun, and the existence of an animal that does not require any precious resources from the sun, is perhaps, an impossibility since the sun is literally unavoidable for most creatures. And that would be true for most insects or spiders, but not for the cave spider.
This type of cave insect lives deep within caves, so it is a properly named spider, but it also never sees any sun as a result of dwelling deep within caves for the entirety of its existence. Since these bugs never receive solar radiation from within their cave environments, these bugs have not developed any pigmentation.
These spiders also prefer to live in the darkest corners of caves because the increased temperatures at the opening of caves can kill this spider. This spider has not evolved to handle the higher temperatures that come from sunlight. This natural sensitivity that these spider have towards sunlight allows them to be used as indicators for subtle changes in climate. A few researchers are looking to the cave dwelling spider as a new means for assessing the rate of climate change.
Have you ever hear of any other type of insect or spider that can live without sunlight?