Spiders can be anoying when you own a CCTV system. Here is a picture of a spiderweb in front of one of my cameras with integrated IR LED illuminator:
You can see that the reflection of IR light on the spiderweb is so strong that the glare hides all details behind the spiderweb.
So when you install an outdoor CCTV camera, think about spiders. Try to position the camera in a place where there are no spiders.
When you google for “CCTV spider repellent”, you will find chemical products that should repel spiders from CCTV cameras. But I’ve not had the opportunity to test out such products, they don’t ship outside their country of sale.