The Jewel Wasp
Biology 342 Fall 2010
Briana Patton and Lisa Schomaker
Exoparacitism in Ampulex compressa
The insect world is rife with parasitism. Millions of years of co-evolution have left some insects at the will of others. The Jewel wasp (Ampulex compressa) begins its life within the belly of a sedated Periplaneta americana, a cockroach which the mother wasp hunted, paralyzed, and left to serve as an edible babysitter for its young hungry larvae. This strategy is common to all wasps of the Ampulicidae family, commonly known as cockroach wasps, but the mode by which they capture and subjugate the cockroach differs among them. (Figure 1. A Periplaneta americana being stung by Ampulex compressa. Photo source 1)
With a carefully delivered sting, the wasp injects a venom directly into the cockroach's head ganglia producing a prolonged period of grooming followed by a hypokinetic state which, if no larva is implanted, can last for several days. During hypokinesis, the wasp grips the cockroach's antennae and leads it to a burrow. The wasp then deposits an egg on the cockroach's belly, seals the burrow, and leaves. Three days later, the larva hatches and begins to feed on the hemolymph of the cockroach. Soon after, the larva bites a hole ix n the cuticle of the cockroach and begins to feed on its internal organs, at which point the host dies. The larva then pupates inside the cockroach's abdomen and emerges from the burrow as a mature adult about five weeks later.