Abstract
Embryonic development of Haplogonatopus atratus in the small brown planthopper Laodelphax striatellus progressed as follows. Superficial cleavage started within 24hr after oviposition. A pair of lobes, probably organs for intake of nutrition to the embryo, was formed on the anterior end of the egg within 48hr. The lobes elongated toward the host intestine. The digestive tract of the parasite differentiated after the lobe formation. The embryo protruded out as a larval sac 8 days after oviposition. Thereafter the embryo exuviated and reached larval stage. The oviposition of H. atratus was also observed on L. striatellus killed by wasp predation. H. atratus attacked and digested the whitebacked rice planthopper, Sogatella longifurcifera, but no oviposition was observed. Both the predation and the oviposition of H. atratus were found on the brown rice planthopper, Nilaparvata lugens. Formation of the lobe and digestive tract was observed in the eggs laid in N. lugens within 24hr after the oviposition, suggesting a countermeasure of the eggs to the defence reactions of the host. The embryos in N. lugens, however, were already encapsulated at this time, and development was thereafter interrupted.
