Zoological Studies

Vol. 38 No. 1, 1999

Invasion of Bacteroids and BEV Bacterium into Oocytes of the Leafhopper Euscelidius variegatus Kirschbaum (Homoptera: Cicadellidae): An Electron Microscopic Study

Wilkin Wai-Kuen Cheung1,* and Alexander H. Purcell2

1Department of Biology, Chinese University of Hong Kong, Shatin, Hong Kong
2Department of Environmental Science, Policy and Management, University of California, Berkeley, CA 94720-3 112, USA

Wilkin Wai-Kuen Cheung and Alexander H. Purcell (1999) Electron microscopic studies were carried out on the infective stages of symbiotic bacteroids a and t, and their chronic pathogen BEV together with ovarioles of the leafhopper Euscelidius variegatus Kirschbaum fixed in situ. The bacteroids were carried in cluster of host cells in the hemolymph as an infective mound during the second day of adult emerge nce. Before entering an ovariole through special wedge cells of the follicular epithelium, they were released as individuals. The BEV bacteria were also carried in infective mounds and were released to the hemolymph for oocyte infection. Host hemocytes (probably plasmatocytes) engulfed bacteroids and BEV bacteria in the hemolymph when they were not protected by host's cell membranes.

Key words: Symbionts, Bacteria, Ovary, Ultrastructure, Insect immunity.

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