Phaeogenes cynarae Bragg is a multivoltine, apparently specific, internal parasitoid of Platyptilia carduidactyla (Riley). P. cynarae attacks prepupae and pupae of the host on the thistles, Cirsium vulgarac and Cynara scolytmus (the globe artichoke), most frequently, has a high searching capacity, and is long-lived when provided with food and water, making it an effective parasitoid of the plume moth host. An olfactory stimulus from wounded host plants is the key stimulus responsible for initiating searching behavior. The key stimulus must be present throughout the entire process of searching, host selection, and oviposition. The key stimulus localizes the search in areas likely to contain host larvae. Tactile stimuli from cracks, rough places, etc., further direct the search on and near the host plant. Actual contact with the larva determines host suitability. The presence of mature ova in the oviducts serves as an endogenous factor in appetitive behavior for searching. Females exhibit an avoidance response within seconds of contacting a host previously parasitized by another P. cynarae female. The mechanism responsible for the avoidance of superparasitism is a pheromone produced in the accessory (venom) gland of the female. The pheromone is injected through the ovipositor at oviposition, and is systemic in action, being capable of detection by subsequent females within 30 s of its injection. This pheromone is injected rather than wiped onto the host through the feet or ovipositor as in other species.
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David E. Bragg (1974) studied this question.