A scorpion neurotoxin increases the potency of a fungal insecticide

The low virulence of the insecticidal fungus Metarhizium anisopliae has stymied its widespread use in controlling insect pests. We show that high-level expression of an insect-specific neurotoxin from the scorpion Androctonus australis in hemolymph by M. anisopliae increases fungal toxicity 22-fold against tobacco hornworm ( Manduca sexta) caterpillars and ninefold against adult yellow fever mosquitoes ( Aedes aegypti) without compromising host specificity. Prelethal effects include reduced mobility and feeding of the insects targeted.