Cantharidin? Who cares! First record of Trichodes feeding on toxic blister beetle (Coleoptera: Cleridae and Meloidae)

Many insects produce and secrete toxic compounds as an anti-predatory strategy. Among beetles, members of the family Meloidae produce cantharidin, a highly toxic terpene well known for its traditional use in popular pharmacology and for its potential use in anti-cancer therapies. This compound is so toxic to avoid predation on Meloidae by most vertebrates and invertebrates. Here we report the first case of predation by Cleridae on blister beetles, specifically by the predator Trichodes crabroniformis on Mylabris variabilis, whose cantharidin content is well known. Only a few other species are known to prey on blister beetles or to be attracted by cantharidin (canthariphilous), which they can ingest and use for different purposes (e.g. defense, female attraction etc.). However, nothing is known about how cantharidin can be transported within these organisms without causing tissue damage. Increasing the knowledge on species that are not damaged by this substance might be relevant for studying the molecular basis of cantharidin tolerance. This might be of great importance also for human medicine, for example for the development of drug delivery systems for cantharidin-based drugs avoiding collateral effects.