EVIDENCE FOR A MARKING PHEROMONE IN HOST DISCRIMINATION BY CEPHALONOMIA-STEPHANODERIS (HYM, BETHYLIDAE)

The bethylid Cephalonomia stephanoderis Betrem is an ectoparasitoid th at prefers to oviposit on the prepupae and pupae of the coffee berry b orer Hypothenemus hampei (Ferrari) (Coleoptera: Scolytidae). It has th e ability to distinguish unparasitized from parasitized hosts and rare ly lays more than one egg per host. The mechanism of this host discrim ination by C. stephanoderis was investigated under laboratory conditio ns. For this, parasitoid eggs that had been deposited on host pupae we re removed and pupae were then offered (individually and collectively) to individual female wasps. A total of 92% of individually offered ho sts and 93% of collectively offered hosts were not parasitized. It is concluded that C. stephanoderis recognizes a marking pheromone deposit ed into or onto the host, preceding, during, or after oviposition whic h enables female parasitoids to avoid self and conspecific superparasi tism.