none Enter Various species parasitise Pieris brassicae. Lying in wait for their prey, these parasitic wasps or parasitoids can perhaps be best described as serial killers. They may hitchhike on the imago in order to find eggs to lay their own eggs in. After mating, the female butterfly gives off an anti-aphrodisiac which makes the wasp's task easier. Alternatively, the wasp may recognise substances given off by the plant in response to the oviposition. Similarly, a wasp species that infects the caterpillar locates its prey by the smell of substances produced as a chemical defence by the plant that is being eaten up. Yet another wasp species lays its eggs either in the newly formed pupa, or in a caterpillar that is just about to pupate; it probably also finds its victim by hitch-hiking, this time on the final instarl The timing of the host's death varies, sometimes the host even caring for the larval brood until the young wasps emerge. However, being a serial killer is not without its own dangers. Hyperparasitoids of these killer wasps lay their eggs in the wasp larvae either while these are still in the host caterpillar or when the wasp larvae have spun themselves a cocoon. The fascinating development of the larvae of Cotesia glomerata in the caterpillar can be seen in English on http://www.youtube.com/watch?v=vMG-LWyNcA Baryscapus galacticus (Eulophidae): [Parasite]. Pteromalus puparum (Pteromalidae): [Parasite]. Trichogramma (Trichogrammatidae): [Parasite]. Cotesia glomerata (Braconidae): [Host, Parasite]. Gelis agilis (Ichneumonidae): [Parasite]. Pieris brassicae (Pieridae): [Host].