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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Insect Genetics and Biochemistry Research » Research » Publications at this Location » Publication #48168


item RIEMANN JOHN G - 5442-05-35
item NEWMAN SAMUEL M - 5450-20-00

Submitted to: Annals Morphology Histology and Fine Structure
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/27/1995
Publication Date: N/A
Citation: N/A

Interpretive Summary: An average of about 150 circular microscopic nodules (discoidal pores) occur on the upper surface of the abdomen of the male greenhouse whitefly. Histological studies show that each nodule is hollow and associated with a single epidermal cell which releases secretory material into the cavity of the nodule. The secretory material moves to the exterior of the nodule through tiny pores. Staining indicates that the secretory material contains a mixture of protein and lipid. The material seems to be mostly lipid. No definite function has been found for the secretory material, but a role in reproduction is suggested by the fact that the nodules occur on only the one sex. A male pheromone or recognition factor is a plausible possibility.

Technical Abstract: A histological study was made of the "discoidal pores" and associated epidermal cells located on the dorsal surface of abdomens of males of the green house whitefly, Trialeurodes vaporariorum (Westwood). A mean of about 150 discoidal pores occurred on each abdomen. Externally each discoidal pore appeared as a circular cuticular tubercle with a diameter of about 3.5 m . Internally, there was a lumen that extended downward and laterally beneath the cuticle. A cuticular network partially subdivided the lumen into two parts. Each tubercle and lumen was associated with a single epidermal cell having about the same thickness as adjacent epidermal cells. Secretory granules, formed in sequestered portions of cytoplasm, were released into the lumen and eventually to the exterior through pores at each of several pits on the surface of each tubercle. Histochemical staining of thick sections indicated the presence of proteinaceous and lipid material in the lumen. Other considerations, such as the presence of only small amounts of rough endoplasmic reticulum, suggested that the secretion was primarily lipid. No direct evidence was found as to possible functions of the secretory material from the discoidal pores, but a reproductive role, such as male recognition, appeared most plausible.