IMMUNOLOGICAL RELATIONSHIPS BETWEEN PARASITE CARDIOCHILES NIGRICEPS VIERICK AND CERTAIN HELIOTHIS SPECIES

Heliothis virescens (F.) made no apparent defensive reaction against the braconid parasite Cardiochiles nigriceps Vierick. The parasite was found to be encapsulated by haemocytes in H. zea (Boddie). The interrelationships between C. nigriceps and each of the Heliothis species were found to be such that the parasite possesses some passive characteristic by which it did not initiate a humoral response in H. virescens but did initiate this humoral response in H. zea. The presence of this humoral response resulted in encapsulation by haemocytes in H. zea and the absence of this humoral response was demonstrated as the reason for the parasite not being encapsulated in H. virescens. The principle of heterophile antigens is suggested as an explanation for the differing responses of these two Heliothis species to this parasite. © 1968.