Heres the things i dunno if this combo will work or not.

i have empress mantis on the field and then i use the insect immitation. will that allow me to summon ultimate insect lv 7 to my side of the field or no?

what does empress mantis and insect immitation do

You may Normal Summon and Special Summon "Ultimate Insect LV7" in any appropriate way, so "Insect Imitation" can Special Summon it. However, the effect of "Ultimate Insect LV7" will only activate if it was Special Summoned by "Ultimate Insect LV5"'s effect.