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Synchronous growth of a parasitoid, Perilitus coccinellae, and teratocytes with the development of the host, Coccinella septempunctata

Kadono-Okuda, Keiko, Sakurai, Hironori, Takeda, Susumu, Okuda, Takashi
Entomologia experimentalis et applicata 1995 v.75 no.2 pp. 145-149
Braconidae, Coccinella septempunctata, adults, diapause, eggs, hemocoel, insect growth, instars, larvae, larval development, methoprene, parasitoids, photoperiod, physiological state, pupae, teratocytes
The relationship between the development of Coccinella septempunctata brucki Mulsant (Coleoptera: Coccinellidae) and its parasitoid, Perilitus coccinellae (Schrank) (Hymenoptera: Braconidae) was studied at two photoperiods (L16:D8 and L12:D12) at 26 °C. The development of P. coccinellae is well synchronized with the physiological state of the host, C. septempunctata, which can be parasitized not only as adult but also as larva or pupa. The parasitoid larva completed larval development within 19 days in a non-diapausing host, while in diapausing adults as well as in pupae held at diapause-averting conditions, the parasitoid larva ceased growth at the first instar. Growth was resumed when diapause of the host terminated or by the emergence of the adult host from the pupa. About 550 spheric cells, teratocytes, were liberated into the host hemocoel when the parasitoid egg hatched. The teratocytes increased in size in the active host, while their development was arrested in the diapausing host. Application of methoprene caused diapause termination of both host and parasitoid larva. The results indicate that the development of the larva of P. coccinellae depends on the physiological conditions of the host, C. septempunctata brucki. The host-parasite relation thus represents an ‘endogenous synchronization' in the sense of Schoonhoven's definition.