Board Thread:Suggestions forum/@comment-27388204-20160110035025/@comment-26172435-20160111070015

Faenor of the Silver Laurel wrote: Actually, it is evidence, as seen through data gathered from a single specimen. Evidence of behaviour, not explaining it.

An explanation: These creatures reduce their activity during daytime to reduce the risk if their bodies overheating as they have limited capacity to release heat. This would also be sufficient explanation for both scorpions and spiders to not pro-actively attack potential threats. The Mirkwood climate may however not be too hot for them to have to switch to passive mode in daytime. The size of the creatures also matters: the bigger the creature, the higher the overheating risk. This could explain the presence of very large spiders in the relatively cold Mirkwood anyway.

So, the notion of spiders and exoskeleton armoured megabugs turning inactive during the heat of day makes sense. No more reservations afaic. :)