Department of Entomology

Title: Parasitoid Jewel Wasp Mounts Multi-Pronged Neurochemical Attack to Hijack a Host Brain

Abstract: The parasitoid emerald jewel wasp Ampulex compressa induces a compliant hypokinetic state in its host, the American cockroach Periplaneta americana through direct venom injection into the central nervous system (CNS). Construction of the jewel wasp venome via combined transcriptomics and proteomics revealed a complex mixture of enzymes, neurotransmitters and novel peptides. Notable among these are metalloproteases and phospholipases, tachykinins, corazonin, adenosine deaminase, and the Toll ligand, Spätzle. Transcriptomic analysis of cockroach brain and subesophageal ganglion yielded sequence information and quantitative expression of corresponding venom targets, suggesting a broad attack encompassing multiple CNS signaling pathways.

We have found that venom signaling molecules are maintained as precursors while in the acidic environment of the venom apparatus. Furthermore, the venom contains sufficient enzyme activity to proteolytically process these into bioactive forms once injected into the neutral pH of the host CNS. Functional analysis of the cockroach tachykinin receptor in vitro validates this hypothesis for venom tachykinin and further investigation is underway to characterize venom attack on adenosine and Toll signaling pathways.

This analysis deepens mechanistic understanding of the interaction between wasp and cockroach as a potential model system for host parasite interactions, studies in molecular co-evolution, and exploration into pathways that integrate sensory information into decision making.