The Spider To The Fly...

Here's a bit of a poser for my Social Media chums. I read a Facebook quote last week saying,

"Normality; What is normal for the spider, is chaos for the fly".

Interesting analogy is it not? At first glance it makes perfect sense, but upon reading it again it seems to be illogical. Given that the spider has some level of evolutionary understanding that their prey is the humble fly, then surely the fly must equally comprehend that their predator is the spider?

Man wouldn't step into a lion enclosure, sit down on a check rug, unscrew the lid on his thermos flask and open a Tupperware box of sandwiches in a calm, collected manner whilst enjoying a picnic. We have collectively evolved to understand that lions, tigers and bears, ("oh my") are our predators. Nor would we jump in a carefree fashion into the Pacific ocean and leisurely swim amongst sharks, knowing full well that they are man eaters.

What I'm getting at is the notion that what is normal for the spider HAS to be just as normal for the fly. Or am I applying some level of Darwinian interpretation that doesn't exist? Is the fly less of a species than the spider? Has the brain of the fly evolved to the same degree as the spider? Does it swarm around the house in summer thinking, "I'd better not go near that eight legged freak in the corner!" Or does it, without any comprehension fly straight into a cobweb without reasoning?

Are there any entomologists in the house who can help me out here?