SYNCHRONOUS GROWTH OF A PARASITOID, PERILITUS-COCCINELLAE, AND TERATOCYTES WITH THE DEVELOPMENT OF THE HOST, COCCINELLA-SEPTEMPUNCTATA

The relationship between the development of Coccinella septempunctata brucki Mulsant (Coleoptera : Coccinellidae) and its parasitoid, Perili tus coccinellae (Schrank) (Hymenoptera: Braconidae) was studied at two photoperiods (L16:D8 and L12:D12) at 26 degrees C. The development of P. coccinellae is well synchronized with the physiological state of t he host, C. septempunctata, which can be parasitized not only as adult but also as larva or pupa. The parasitoid larva completed larval deve lopment within 19 days in a non-diapausing host, while in diapausing a dults as well as in pupae held at diapause-averting conditions, the pa rasitoid larva ceased growth at the first instar. Growth was resumed w hen diapause of the host terminated or by the emergence of the adult h ost from the pupa. About 550 spheric cells, teratocytes, were liberate d into the host hemocoel when the parasitoid egg hatched. The teratocy tes increased in size in the active host, while their development was arrested in the diapausing host. Application of methoprene caused diap ause termination of both host and parasitoid larva. The results indica te that the development of the larva of P. coccinellae depends on the physiological conditions of the host, C. septempunctata brucki. The ho st-parasite relation thus represents an 'endogenous synchronization' i n the sense of Schconhoven's definition.