I think it's pointless to think like that. Humans, to aliens who want earth, are like hornets that are in the way. If you know what hornets are, and that they're mean bastards, you don't attack them with better stingers, and it doesn't matter how eager they are to sacrifice themselves for the nest.

Aliens would use pesticides and we'd never see them coming. See "The Screwfly Solution".

https://en.wikipedia.org/wiki/The_Screwfly_Solution