The second mecha will be a spaceship transform into a robot.

I want an insect sentai. I was thinking the team shoukd go like this:

Red: Japanese rhinoceros beetle
Blue: Dragonfly
Green: Praying Mantis or Grasshopper
Yellow: Bee
Pink: Ladybug or Butterfly
Sixth (Unknown Color): Stag Beetle or Spider ( I know spiders aren't insects, but the sixth rangers are always different)

Give me some suggestions on the mecha, sixth ranger color, or what insect green, pink, and sixth should have. Should it have more rangers?

I doubt something like that gonna happen.

Realistically, I have to agree with 7L, insect sentai (an entire team and not just sixth rangers/secondary team) will not happen as long as the superior money-maker Kamen Rider is on the air.

It should not be a problem if super sentai goes all buggy on us.
Heck, it has been 9 years since we had a proper insect rider so why not. And OOO does not count since that is only 1/3 of an insect and Gatakiriba is not the primary form for OOO, so yeah. :lolol

How would be a plot of a insect sentai ?

If it happened, like any other sentai. Villains want to attack Earth and a team comes together and stops them. If Ant-Man does really well, I think we could get another insect themed rider. A rider that can shrink to fight? It could work...I guess...

I don't know anything about kamen rider, lol

For the insect sentai, the villains could be spiders, so it would insects vs arachnids. I don't want them to be alien spiders. The whole alien villain theme is to common, I want them to be normal spiders that mutated. I need help on what the morpher and collectable device should be.

Mutants are pretty cliché also but that is one of the charms of sentai new variations on a cliché or trope. Lol

Have you seen a Super Sentai?
So much of the series is based around cliches that it shows their true creativity by working around those cliches and using them to their advantage. Putting a unique twist on a tired concept. It doesn't change the concept as a whole, but it makes it interesting.