The monster selected for "Jade Insect Whistle" is chosen when the effect resolves, not when it is activated, so "Jade Insect Whistle" doesn't target.
If your opponent claims to have no Insect-Type monsters in his/her Deck when your "Jade Insect Whistle" resolves, you can check the Deck to make sure.
A face-up "Parasite Paracide" can be selected with "Jade Insect Whistle".