"Insects are pharmacophagous if they search for certain secondary plant substances directly, take them up, and utilize them for specific purpose other than primary metabolism or (merely) foodplant recognition."
Boppré M (1984) Redefining "pharmacophagy". J Chem Ecol 10: 1151-1154. read
Insects of different orders (Lepidoptera, Coleoptera, Diptera, Orthoptera) purposefully and usually idependent of gathering food (i.e. "pharmacophagously") take up pyrrolizidine alkaloids (PAs) from plants and use them as precursors of pheromones and/or as defensive chemicals. This leads to questions re morphology, physiology, ethology but also re ecological, chemical and evolutionary ones. We study comparatively numerous species and aim to describe insect-PA relationships and elucidate direct and indirect effects / roles of these secondary plant metabolites for insects.
Pharmacophagy is not restricted to pyrrolizidine alkaloids but occurs with other secondary plant and insect chemicals and is also exhibited by vertebrates.