Speaking of Portias and smarts, I'm just going to recommend "Children of Time" here (and its recently released sequel, "Children of Ruin"). It's a story of a future where humans accidentally uplifted jumping spiders instead of monkeys, and goes deeply into how the minds, societies and technology of such spiders would be fundamentally different from our own.
>Something about predatory nature of both insects seems to tune up their intelligence.
Yep. To be a predator, you need to outwit your prey and think fast, so it's thought to be a natural INT grinder. `w´
Presumably, this could drive up the INT of prey too, but maybe it's cheaper to just be faster/harder to see? But you can't be THAT hard to see, and the speed only saves you in failed ambushes, so planning successful ambushes continues to reward the INT of predators (unless they just enter the speed arms race, like cheetahs or tiger beetles).
They are creepy smart.