10 - Cantharidin Biosynthesis and Function in Meloid Beetles

Abstract

Cantharidin, a teφenoid substance found in blister beetles, is among the most widely known insect natural products in the world. Its reputation derives principally from descriptions of its physiological activities, most notably as an aphrodisiac for humans and livestock, that are traced from oral history. Cantharidin is also the blistering agent that earned these bettles their common name. These diverse effects on humans are paralleled by activities that the beetles exploit in their reproduction and ecology. The chapter explores the latter perspective of cantharidin's role—the pheromonal and other adaptive functions of cantharidin in blister beetles. The chapter discusses the chemical and biosynthetic knowledge of cantharidin to build a foundation for understanding its ecological roles in blister beetles. The intriguing simplicity of the cantharidin structure belies not only the difficulties encountered establishing the details of its molecular structure but also the complexity of the metabolic process involved in its formation by blister beetles. Comparison of its structure to those of known metabolic origin readily suggests that this compound belongs to the terpenoid biosynthetic class of natural products.