Well... I think the insect classification is a rough one, as with all of the classifications in the game. Insects as we know them need a very oxygen rich atmosphere to grow large. Since many of the insect races live on volcanic worlds, this suggests to me that they have a significantly altered metabolism from earth based insects. While they do procreate at a somewhat higher rate, it isn't higher enough to really differentiate them from other species in the game, and they certainly don't breed at the rate most insects do on Earth. The argument could be made that they procreate and die off quickly, but this isn't reflected in the characters screen. Further, several insect races have 5 year cycles during which their behavior is altered. This suggests to me that each individual insect lives a number of decades, probably between 30 and 120 earth years.
Anyway, insect life in the game generally seems to be human scale, long lived, and really quite different than insects on Earth. They do exhibit some insect behaviors, but no more really than humans act like lesser primates.