My favorite insect is the jewel wasp. It's a parasitoid that exhibits remarkable host behavioral manipulation. After locating a cockroach, it's host animal, the wasp first injects a paralytic into the cockroach's legs, rendering it unable to move. It then injects venom directly into the head of the cockroach, targeting the specific regions of the "brain". The venom mimics dopamine as well as GABA, making the host docile and unwilling to flee or fly. The wasp then leads the cockroach to a burrow and lays an egg in the host that hatches and devours the cockroach alive over the course of a week.
