Skip to main content
ARS Home » Research » Publications at this Location » Publication #91393
Title: CHORION FORMATION AND ULTRASTRUCTURE OF THE EGG OF THE CAT FLEA, CTENOCEPHALIDES FELIS, (SIPHONAPTERA: PULICIDAE)

Author
item MARCHIONDO, ALAN - MERIAL LIMITED
item Meola, Shirlee
item PALMA, KATHLEEN - BLUE RIDGE PHARMACEUTICAL
item SLUSSER, JAMES - VIRGINIA MEDICAL SCHOOL
item MEOLA, ROGER - TEXAS A&M UNIVERSITY

Submitted to: Journal of Medical Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/28/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: Insect growth regulators are a class of insecticides that are important in controlling insects because they are effective and because they are environmentally-friendly. The insect growth regulator in our study was lufenuron, the main ingredient in Program, one of the most common insecticides prescribed by veterinarians for flea control. Our study was done to determine how lufenuron kills fleas; it acts by preventing the proper development of the skin (cuticle) of the flea. We also showed that this occurs in the immature stage of flea which means the immature fleas never become adults.

Technical Abstract: The formation and ultrastructure of the egg shell of the cat flea, Ctenocephalides felis was studied as a basis for development of new methods for controlling these economically important pest insects. As oocytes develop, somatic follicle cells produce electron-dense granules that through exocytosis and coalescence, form the vitelline and chorionic membranes around the oocyte. The chorion was found to consist of five distinct layers: an external layer containing widely dispersed electron-dense spheres, a second layer of densely packed granules, a relatively thick, weakly laminated third layer and a thin, electron dense basal layer. The third and basal layer are separated by an air space that contains projections of the third layer that extend to the basal layer as pillars. This air-filled region is the palisades or trabecular layer that forms the major respiratory organ of the eggshell. The air spaces of the trabecular layer are connected to the external environment by the pores of the lateral and anterior aeropyles on the surface of the eggshell. The chorion of this egg lacks an inner chorionic and a wax layer that have been report in eggs of insects subjected to desiccation. The outermost layer of the chorion containing the spherules appears to be unique to the eggs of fleas.